Introduction
Background
The increasing frequency of autologous hematopoietic stem cell transplant (autoHSCT) to treat hematologic malignancies, especially among older adults, has contributed to increased survival [ 1 , 2 ]. AutoHSCT is preceded by myeloablative induction chemotherapy [ 3 ], which often leads to deconditioning and worsening of symptoms before transplant [ 4 , 5 ]. These pretransplant treatment-related impacts could predispose patients to altered mobility (ie, altered gait and balance) that could worsen after transplant and threaten patient’s functioning and quality of life [ 6 , 7 ]. Mobility declines have broad health implications, as patients undergoing transplants who report low physical functioning are at high risk for morbidity and mortality following transplant [ 8 , 9 ]. Over the past few years, a few studies have evaluated the feasibility and potential clinical utility of wearable sensors in the oncology setting [ 10 - 12 ]. Wearable sensors could describe specific patterns of mobility impairment and their potential attribution to treatment-related symptoms and potentially identify patient risk at discrete intervals along the treatment trajectory. In turn, this information could be used to inform timing and design of rehabilitation and symptom management strategies to positively affect clinical outcomes for the patient with hematologic cancer [ 13 ].
Before transplant, patients undergo conditioning therapy, which can include any combination of radiation therapy, immunotherapy, or induction chemotherapy [ 3 ], all of which cause treatment-related symptoms and side effects that may linger into transplant [ 14 ]. Induction chemotherapy, in particular, can cause symptoms known to affect mobility including fatigue, neuropathy, vestibular dysfunction, dizziness, and pain [ 15 ]. Symptom clusters in patients undergoing transplant include fatigue, weakness, and anorexia; anxiety and depression; and nausea and vomiting [ 16 ]. These symptom clusters are associated with decreased self-reported physical functioning during autoHSCT and increased fall risk [ 17 , 18 ]. Current knowledge has relied on patient-reported measures of physical functioning, which can be less sensitive and informative and more prone to bias than objective measures of mobility and functioning [ 19 , 20 ]. It is also possible that using self-report may underestimate the degree of functional limitation among patients before autoHSCT. In addition, identifying the potential influence of treatment-related symptoms that are present at the time of transplant on mobility could identify patients at high risk for further decline after autoHSCT and who could benefit from appropriately timed rehabilitation and symptom management.
Objective mobility measurements can assess turning, gait, and balance during prescribed tasks, such as walking at a usual pace, walking while turning, and standing in place. Using technology to capture mobility measures can provide greater precision, sensitivity, and granularity of information than clinical or field tests [ 21 - 23 ]. Characterizing the mobility characteristics of turning, gait, and balance using indices of support, stance, swing, spatial temporal patterns, stability, and range of motion typically requires advanced laboratory techniques (ie, motion cameras) that limit their application in nonresearch settings. Advancements in wearable sensors to quantify the same laboratory-based assessments in a clinic or home setting widen the scope of objective mobility assessment to include clinical populations undergoing intensive treatment and requiring hospitalization, such as patients undergoing autoHSCT. So far, a single study using insole sensors to measure gait patterns in patients after receiving allogeneic hematopoietic stem cell transplant (HSCT) reported slower walking speeds and shorter stride times than healthy matched controls, suggesting that treatment may have altered gait [ 24 ]. However, as gait was measured after treatment, it remains unknown whether patients already experienced some mobility limitations from treatments before transplant and whether and which persistent symptoms may be associated with mobility in patients receiving autoHSCT.
Objectives
We conducted a cross-sectional study using wearable inertial sensors to measure mobility in patients with hematologic cancer after induction chemotherapy and before autoHSCT to identify (1) differences in mobility between patients and age-matched controls and (2) whether and which symptoms typically related to chemotherapy may be associated with pretransplant mobility in patients.
Methods
Study Design
We used a case-control design to compare the mobility of 78 patients with hematologic cancer before transplant with that of healthy age-matched controls and a cross-sectional design to identify chemotherapy-related symptoms associated with mobility in patients.
Participants and Setting
Eligible patients were recruited through the Oregon Health & Science University Knight Cancer Institute Center for Hematologic Malignancies HSCT unit. Eligible patients were those who were scheduled to receive autoHSCT for a hematopoietic or lymphatic malignancy, were aged ≥21 years at the time of enrollment, had no cognitive difficulties that precluded completing surveys, were participating in performance testing, provided informed consent, and had no preexisting medical conditions that significantly affect mobility (ie, severe dystrophy, severe spasticity, epilepsy, seizures, Alzheimer disease, dementia, severe balance disorder, and inability to ambulate independently). Patients completed assessments after the completion of initial induction chemotherapy and within 2 weeks before hospitalization for autoHSCT.
Age-Matched Controls
Age-matched controls were selected from a preexisting sample of healthy adults recruited from the local community for 2 study protocols [ 25 , 26 ]. Eligible controls had no history of falls, chronic diseases including cancer, significant neurological or musculoskeletal impairment, or medication use that affects mobility or limits their ability to follow instructions or provide informed consent. Controls were age-matched to participants according to age at the time of assessment within 1 year.
Ethics Approval
The Oregon Health & Science University institutional review board approved the study (16760), and informed consent was obtained from all participants before data collection. Participant data were deidentified using individual code numbers assigned upon enrollment. Participants were not compensated for participating in the study. The survey and mobility assessment took approximately 30 to 45 minutes to complete and thus was not considered to pose a significant burden to participants.
Demographic Measurements
Patient demographics (age, sex, ethnicity or race, education, marital status, employment, and history of falls in the previous year) were self-reported. Comorbidities were determined using the Functional Comorbidity Index, a self-administered 18-item checklist of chronic conditions that affect physical functioning [ 27 ]. Self-reported cancer diagnosis and treatment history were adjudicated by the research staff. Height and weight were measured in the clinic, and BMI was calculated as kg/m 2 . The control group’s self-reported demographic data included age, sex, height, weight, health history, and education.
Objective Mobility Assessment
Objective mobility measures were assessed using Mobility Lab (APDM, Inc), a portable system of unobtrusive, body-worn, wireless, inertial sensors that quickly and automatically provide objective mobility measures, including turning, gait, and balance [ 28 - 30 ]. Patients’ Mobility Lab assessments were collected in the clinic using available space (eg, hallways) during a single appointment. Participants wore inertial sensors (Opal; APDM, Inc), placed at the sternum, lumbar spine, wrists, and ankles ( Figure 1 ), and performed 2 standard physical functioning assessments—a 6-minute walk test (6MWT) and a 30-second quiet stance [ 19 ]. The 6MWT assesses distance walked over 6 minutes and is one of the most established outcome measures of functional mobility in clinical trials [ 31 , 32 ]. Participants walked at their usual pace for 6 minutes on a 20-meter course. Each full lap provided gait and turns averaged together, considerably reducing variability and performance bias compared with a single walk [ 33 , 34 ]. For controls, if a 6MWT was not performed owing to differences in protocol at the time of consent, a 400-meter walk was completed [ 25 , 26 ], which provides similar estimates of turning and gait [ 35 ]. Balance was measured using a 30-second quiet stance test, where participants stood as still as possible for 30 seconds with eyes open, feet together, and hands on their hips. Measures specific to turning, gait, and balance selected for these analyses ( Table 1 ) have been previously used to assess fall risk, including dynamics during turning, postural adjustments associated with step initiation, spatial and temporal components of gait, and postural sway during standing balance [ 25 , 36 - 38 ]. Data processing was performed using Mobility Lab (version 2; APDM, Inc) and established algorithms [ 28 , 39 ]. The algorithms account for difference in physical stature (eg, height) of participants and in physical functioning assessment protocols for samples recruited at different times, allowing for a large sample of community-dwelling healthy adults with valid mobility data to select age-matched controls.

Table 1
Definitions of selected Mobility Lab mobility measures of turning, gait, and balance.
a 6MWT: 6-minute walk test. b ROM: range of motion. c RMS: root mean square.
| Measure | Definition | |
| Turning (6MWT a ) | ||
| Turn duration (s) | Duration of 180° turn | |
| Number of steps | Number of steps during 180° turn | |
| Gait (6MWT) | ||
| Gait speed (m/s) | Forward speed of the individual, measured as the forward distance traveled during the gait cycle divided by the gait cycle duration | |
| Stride time (s) | Duration of a full gait cycle, measured from the left foot’s initial contact to the next initial contact of the left foot | |
| Stride time variability (%) | Coefficient of variation stride length (SD/mean) | |
| Double support time (%) | Rate of gait cycle while both feet are on the ground | |
| Coronal trunk ROM b (°) | Angular range of the lumbar spine in the coronal plane | |
| Heel strike angle (°) | Angle of the foot at the point of initial contact; the pitch of the foot is 0 when flat and positive when the heel contacts first | |
| Stride length (m) | Forward distance traveled by a foot during a gait cycle | |
| Distance (m) | Total distance traveled during the timed test, at usual walking speed | |
| Balance (30-second quiet stance) | ||
| Coronal sway RMS c (m/s 2 ) | Amplitude of lateral sway | |
| Coronal range (m/s 2 ) | Angular range of the lateral thoracic spine (roll) | |
| Coronal velocity (m/s) | Mean velocity of lateral sway | |
| Coronal centroidal frequency (Hz) | Frequency of centroidal lateral sway | |
| Sagittal sway RMS (m/s 2 ) | Amplitude of anterior-posterior sway | |
| Sagittal range (m/s 2 ) | Angular range of the anterior-posterior thoracic spine (pitch) | |
| Sagittal velocity (m/s) | Mean velocity of anterior-posterior sway | |
| Sagittal centroidal frequency (Hz) | Frequency of centroidal anterior-posterior sway |
Patient-Reported Symptoms
Overview
For patients scheduled for autoHSCT, validated, patient-reported outcomes on symptoms typically associated with chemotherapy were collected using the following instruments and administered electronically in REDCap (Research Electronic Data Capture; Vanderbilt University) [ 40 ]. High scores indicate high level of symptoms for all questionnaires, unless otherwise described. Symptoms were not assessed for controls.
Chemotherapy-Induced Peripheral Neuropathy
Numbness, tingling, or uncomfortable sensations in hands and feet over the previous 7 days were measured using the 4-item Functional Assessment of Cancer Therapy/Gynecologic Oncology Group–Neurotoxicity subscale, a reliable and valid measure of chemotherapy-induced peripheral neuropathy (score range 0-16, where high scores indicate less-severe chemotherapy-induced peripheral neuropathy; minimally clinically important difference [MCID] 1.38-3.68) [ 41 ].
Nausea and Pain
Symptoms during the previous week were assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire–nausea or vomiting and pain symptom subscales (score range 0-100; MCID 2.4-15.5 [nausea] and 14.4-28.5 [pain]) [ 42 , 43 ]. This questionnaire is an acceptable measure of chronic pain [ 44 ].
Fatigue
Fatigue over the previous week was determined using the Patient-Reported Outcomes Measurement Information System Fatigue Short Form 8a (score range 0-100; MCID 3-5) [ 45 , 46 ].
Vertigo
The Vertigo Symptom Scale–short form was used to measure vertigo, dizziness, and somatic anxiety over the past month (score range 0-60; MCID 3) [ 47 , 48 ].
Depression
Depressive symptoms over the past week were assessed using the Center for Epidemiological Studies–Depression scale (score range 0-16; MCID 9-11) [ 49 , 50 ].
Statistical Analysis
Distributions were inspected for normality; balance measures were log transformed to improve normality, but model results were consistent; therefore, nontransformed variables and parametric tests were used for all analyses. Demographic characteristics were assessed using descriptive statistics, and paired, 2-sided t tests were used to determine the differences in mobility between patients and matched controls.
Linear regression models were used to determine the association between symptoms and mobility. Univariate linear regression models with α≤.05 were used to determine the model demographic control variables. The final models were adjusted for age, sex, and BMI. Symptom selection criteria for linear regression models were determined using Pearson correlations to mobility characteristics, with cutoff points ρ≥0.3 and α≤.10 [ 51 ]. Final stepwise multivariable linear regression models were built using α≤.05 with any mobility characteristic to symptoms and were externally validated with 1000 bootstrap replications. Variability of symptoms in mobility characteristics was estimated using standardized ß coefficients. Post hoc Benjamini-Hochberg false discovery rate adjustment [ 52 ] with α=.05 was completed for paired t tests and linear regression models. Analyses were completed using STATA (version 16.1; StataCorp, LLC), with α≤.05 for statistical significance.
Results
Participants
Between August 2017 and May 2019, 78 patients completed the Mobility Lab assessments before autoHSCT. The average age of patients before transplant was 60.3 (SD 10.3; range 31-76) years, and the most common cancer diagnosis was multiple myeloma ( Table 2 ). The mean time since diagnosis to the scheduled autoHSCT was 9.9 (SD 11) months. All patients (78/78, 100) received induction chemotherapy before autoHSCT, with the average induction chemotherapy regimen lasting 4.7 (SD 3.2) months. In the year before the transplant, 17% (13/78) of the patients experienced a fall. The average age of matched controls (78/156, 50%) was 60.2 (SD 10.4) years. Most patients were men (50/78, 64%), whereas most controls were women (57/78, 73%). Controls had lower BMI and attained higher level of education than patients, and the control group had a high proportion of women compared with the patient group.
Table 2
Demographics and clinical characteristics of patients with hematologic cancer scheduled for autoHSCT a compared with that of healthy, age-matched controls (N=156).
a autoHSCT: autologous hematopoietic stem cell transplant. b N/A: not available; data were not collected for controls. c Collapsed category including individuals who self-reported as being Asian, Black, or American Indian or Alaska Native or having >1 race. d Percentages may not add up to 100% owing to rounding. e Collapsed category including individuals who self-reported as being retired, unemployed, or homemaker. Disability status was not captured. f Staging for multiple myeloma included International Staging System, Revised International Staging System, and Durie-Salmon staging classifications. g Missing data <10%.
| Characteristics | Patients scheduled for autoHSCT (n=78, 50%) | Healthy controls (n=78, 50%) | |
| Age (years), mean (SD) | 60.3 (10.3) | 60.2 (10.4) | |
| Sex, n (%) | |||
| Female | 28 (36) | 57 (73) | |
| Male | 50 (64) | 21 (27) | |
| Ethnicity, n (%) | |||
| Non-Hispanic | 69 (88) | N/A b | |
| Declined to answer | 9 (12) | N/A | |
| Race, n (%) | |||
| White | 63 (81) | N/A | |
| Non-White c | 5 (6) | N/A | |
| Declined to answer | 10 (13) | N/A | |
| Education, n (% d ) | |||
| High school diploma or equivalent | 20 (26) | 2 (3) | |
| Some college or associate degree | 18 (23) | 8 (10) | |
| Bachelor’s degree or higher | 31 (40) | 68 (87) | |
| Declined to answer | 9 (12) | N/A | |
| Marital status, n (%) | |||
| Married or living with partner | 53 (68) | N/A | |
| Divorced or separated | 7 (9) | N/A | |
| Single | 11 (14) | N/A | |
| Declined to answer | 7 (9) | N/A | |
| Employment, n (%) | |||
| Full time | 23 (29) | N/A | |
| Part time | 6 (8) | N/A | |
| Not working e | 39 (50) | N/A | |
| Declined to answer | 10 (13) | N/A | |
| BMI (kg/m 2 ), mean (SD) | 29.8 (5.7) | 25.2 (3.5) | |
| Height (m), mean (SD) | 1.7 (0.1) | 1.6 (0.1) | |
| Weight (kg), mean (SD) | 88.9 (21.2) | 66.3 (15.1) | |
| Cancer diagnosis, n (%) | |||
| Multiple myeloma | 53 (68) | N/A | |
| Hodgkin lymphoma | 6 (8) | N/A | |
| Non-Hodgkin lymphoma | 19 (24) | N/A | |
| Cancer stage f , n (%) | |||
| I | 11 (14) | N/A | |
| II | 21 (27) | N/A | |
| III | 21 (27) | N/A | |
| IV | 12 (15) | N/A | |
| Missing or unknown | 13 (17) | N/A | |
| Time since diagnosis (months), mean (SD) | 9.9 (11) | N/A | |
| Received induction chemotherapy, n (%) | 78 (100) | N/A | |
| Duration of induction chemotherapy (months), mean (SD) | 4.7 (3.2) | N/A | |
| Time since last induction chemotherapy (days), mean (SD) | 20.2 (91.9) | N/A | |
| Received radiation treatment, n (%) | 14 (18) | N/A | |
| Functional Comorbidity Index score g , mean (SD) | 1.3 (1.3) | N/A | |
| History of fall in past year, n (%) | 13 (17) | N/A |
Objective Mobility
Mobility was significantly worse across most measures among patients than among controls ( Table 3 ). In the 6MWT, turn duration was 0.28 (SD 0.54) seconds longer for patients than for controls ( P <.001). Patients demonstrated an altered gait pattern, as exhibited by significantly slower gait speed (mean −0.32, SD 0.25 seconds), longer stride time (mean 0.13, SD 0.13 seconds), higher stride time variability (mean 1.07%, SD 1.42%), longer double support time (mean 5.91%, SD 4.23%), shallower heel strike angle (mean 0.81°, SD 3.56°), shorter stride length (mean −0.18, SD 0.19 m), and shorter distance traveled (mean −60.01, SD 93.49 m) than controls ( P <.001). During standing balance, patients had significantly larger coronal sway (mean 0.02, SD 0.03 m/s 2 ; P <.001), longer coronal range (mean 0.10, SD 0.16 m/s 2 ; P <.001), higher coronal velocity (mean 0.03, SD 0.10 m/s; P =.02), lower coronal centroidal frequency (mean −0.11, SD 0.39 Hz; P =.02), and longer sagittal range (mean 0.08, SD 0.27 m/s 2 ; P =.008) than controls. Sensitivity analyses restricting the analytical sample to controls with gait data from the 6MWT (31/78, 40%) or who were both age-matched and sex-matched (44/78, 56%) yielded results consistent with those obtained using the full sample of controls.
Table 3
Comparison of mobility measures of turning, gait, and balance between patients with hematologic cancer scheduled for autoHSCT a and age-matched healthy controls.
a autoHSCT: autologous hematopoietic stem cell transplant. b Paired, 2-sided t test, with Benjamini-Hochberg false discovery rate adjustment set at α=.05, and all significant P values remained significant. c ROM: range of motion. d RMS: root mean square.
| Measures | Patients scheduled for autoHSCT, mean (SD) | Healthy controls, mean (SD) | Difference, mean (SD) | P value b | |
| Turning | |||||
| Turn duration (s) | 2.43 (0.37) | 2.15 (0.40) | 0.28 (0.54) | <.001 | |
| Number of steps | 4.04 (0.68) | 4.07 (0.78) | −0.03 (0.97) | .82 | |
| Gait | |||||
| Gait speed (m/s) | 1.11 (0.19) | 1.43 (0.15) | −0.32 (0.25) | <.001 | |
| Stride time (s) | 1.14 (0.11) | 1 (0.08) | 0.13 (0.13) | <.001 | |
| Stride time variability (%) | 3.55 (1.25) | 2.48 (0.71) | 1.07 (1.42) | <.001 | |
| Double support time (%) | 23.24 (3.62) | 17.33 (2.99) | 5.91 (4.23) | <.001 | |
| Coronal trunk ROM c (°) | 7.14 (2.68) | 6.33 (2.66) | 0.81 (3.56) | .06 | |
| Heel strike angle (°) | 23 (5.57) | 26.32 (4.23) | −3.32 (6.47) | <.001 | |
| Stride length (m) | 1.25 (0.16) | 1.43 (0.13) | −0.18 (0.19) | <.001 | |
| Distance (m) | 375.76 (64) | 435.78 (55.91) | −60.01 (93.49) | <.001 | |
| Balance | |||||
| Coronal sway RMS d (m/s 2 ) | 0.06 (0.02) | 0.04 (0.02) | 0.02 (0.03) | <.001 | |
| Coronal range (m/s 2 ) | 0.33 (0.13) | 0.23 (0.09) | 0.10 (0.16) | <.001 | |
| Coronal velocity (m/s) | 0.10 (0.06) | 0.07 (0.07) | 0.03 (0.10) | .02 | |
| Coronal centroidal frequency (Hz) | 1.05 (0.32) | 1.16 (0.26) | −0.11 (0.39) | .02 | |
| Sagittal sway RMS (m/s 2 ) | 0.08 (0.04) | 0.07 (0.04) | 0.01 (0.05) | .06 | |
| Sagittal range (m/s 2 ) | 0.43 (0.22) | 0.34 (0.16) | 0.08 (0.27) | .008 | |
| Sagittal velocity (m/s) | 0.15 (0.08) | 0.13 (0.14) | 0.02 (0.15) | .26 | |
| Sagittal centroidal frequency (Hz) | 0.95 (0.22) | 0.96 (0.24) | −0.01 (0.32) | .83 |
Mobility and Chemotherapy-Related Symptoms
Of the 78 patients with mobility data, 69 (88%) completed the patient-reported chemotherapy-related symptom questionnaires ( Table 4 ). Reasons for missing questionnaires included incomplete responses, refusal, or acute illness. Patients with missing symptom data did not significantly differ from those with complete data on age ( P =.73), BMI ( P =.97), sex ( P =.57), or Functional Comorbidity Index ( P =.91); therefore, complete case analysis was conducted. Models were built for symptoms associations with gait only, because prespecified criteria for building regression models were met for symptoms and gait but not for turning or balance measurements. Symptoms that remained significantly associated with any gait metric were nausea and pain ( Table 5 ). High nausea was associated with great stride time variability (ß=.023, 95% CI −0.007 to 0.039) and shallow heel strike angle (ß=−.088, 95% CI −0.160 to −0.017). High pain was associated with slow gait speed (ß=−.003, 95% CI −0.004 to –0.001), short stride length (ß=−.002, 95% CI −0.003 to −0.001), short distance (ß=−.786, 95% CI −1.321 to −0.252), and great stride time variability (ß=.012, 95% CI −0.002 to −0.023). Nausea better explained the variance in stride time variability (33%) and heel strike angle (31%), whereas pain better explained the variance in gait speed (36%), stride length (35%), and distance (34%).
Table 4
Chemotherapy-related symptom intensity among patients with hematologic cancer scheduled for autoHSCT a (n=69).
a autoHSCT: autologous hematopoietic stem cell transplant. b MCID: minimally clinically important difference. c CIPN: chemotherapy-induced peripheral neuropathy.
| Chemotherapy-related symptom | Measure possible score, range | Measure MCID b , range | Sample score, mean (SD) | Sample score, range |
| CIPN c | 0-16 | 1.38-3.68 | 13.01 (3.63) | 0-16 |
| Nausea | 0-100 | 2.4-15.5 | 11.35 (18.63) | 0-100 |
| Pain | 0-100 | 14.4-28.5 | 27.05 (29.02) | 0-100 |
| Fatigue | 0-100 | 3-5 | 53 (7.84) | 33.1-69.8 |
| Vertigo | 0-60 | 3 | 4.81 (5.74) | 0-31 |
| Depression | 0-60 | 9-11 | 9.19 (7.81) | 0-39 |
Table 5
Associations between chemotherapy-related symptoms and gait characteristics among patients with hematologic cancer scheduled for autoHSCT a (n=69).
a autoHSCT: autologous hematopoietic stem cell transplant. b Linear regression models adjusted for age, sex, and BMI, with Benjamini-Hochberg false discovery rate adjustment set at α=.05, and all significant P values remained significant. c ROM: range of motion.
| Gait characteristics | Nausea | Pain | ||||
| ß coefficient (95% CI) | Standardized ß coefficient | P value b | ß coefficient (95% CI) | Standardized ß coefficient | P value b | |
| Gait speed (m/s) | −.002 (−0.005 to 0.0003) | −.189 | .09 | −.003 (−0.004 to −0.001) | −.355 | .003 |
| Stride time (s) | .001 (−0.001 to 0.002) | .127 | .28 | .001 (−0.0001 to 0.002) | .221 | .07 |
| Stride time variability (%) | .023 (−0.007 to 0.039) | .331 | .005 | .012 (−0.002 to 0.023) | .275 | .02 |
| Double support time (%) | .018 (−0.028 to 0.064) | .09 | .43 | .014 (−0.017 to 0.044) | .104 | .38 |
| Coronal trunk ROM c (°) | .027 (−0.011 to 0.066) | .165 | .16 | −.033 (−0.058 to 0.007) | −.310 | .16 |
| Heel strike angle (°) | −.088 (−0.160 to −0.017) | −.305 | .02 | −.026 (−0.074 to 0.021) | −.141 | .28 |
| Stride length (m) | −.001 (−0.003 to −0.0005) | .174 | .13 | −.002 (−0.003 to −0.001) | −.349 | .004 |
| Distance (m) | −.662 (−1.464 to 0.140) | −.184 | .10 | −.786 (−1.321 to −0.252) | −.340 | .005 |
Discussion
Principal Findings
To the best of our knowledge, this study is the first to measure pretransplant mobility in patients with hematologic cancer using an innovative system of wearable inertial sensors to characterize patients’ mobility compared with that of healthy adults and determine whether symptoms may identify patients with altered mobility characteristics. Mobility was significantly worse for patients than for controls, indicating that chemotherapy may directly or indirectly alter systems that control turning, gait, and balance. Among patients, those with high levels of nausea and pain before transplant had worse gait characteristics, demonstrating a conservative gait pattern of slow shuffled walking associated with functional limitations and fall risk [ 53 - 55 ].
Comparison With Previous Studies
Wearable inertial sensors that measure multiple characteristics of turning, gait, and balance could better describe the mobility patterns affected by induction chemotherapy than self-report or field tests. Although other studies have only assessed gait, typically using a timed single walk test, our wearable sensor detected an aggregate of gait alterations in patients, along with differences in turning and balance. Gait parameters in our sample of patients were similar to those in a previous analysis using insole-worn sensors in a small sample of patients several months after allogenic HSCT [ 24 ]; however, our study provided great sensitivity by including additional gait metrics. These findings are consistent with slow and conservative gait patterns comparable with adults who are 20 years older [ 24 , 56 ], suggesting that patients may experience accelerated aging from induction chemotherapy [ 57 ]. The slow gait speed observed in our sample, consistent with previous findings in patients undergoing transplant [ 24 ], is concerning, given that slow gait speed at diagnosis is associated with subsequent hospitalizations and worse survival in older patients with hematologic malignancies [ 58 ]. Patients had a longer turn duration than controls, a measure associated with increased fall risk [ 59 ]; however, patients and controls took, on average, the same number of steps per turn. Increased double limb support time associated with falls [ 60 ] is a compensatory mechanism to make walking more secure with less time spent in single limb support. Gait may compensate for impaired balance [ 61 , 62 ], and thus, increased variability of gait characteristics could be owing to both compensatory mechanisms for balance deficits and multijoint incoordination. Control of balance while walking involves adjusting foot placement. Both variability in foot placement and double support time while walking also reflect impaired balance.
Postural sway during normal, quiet standing has long been shown to be a sensitive measure of balance control, with large, fast sway being associated with increased fall risk [ 63 ]. Consistent with other studies, primarily in survivors of breast cancer, patients exhibited worse balance, likely exacerbated by chemotherapy [ 26 , 64 , 65 ]. Sagittal and coronal sway values observed in our sample were worse than those previously associated with falls in elderly populations [ 66 ]. Chemotherapy can have neurologic and musculoskeletal impacts affecting mobility including distal sensory loss, ototoxicity, myelopathy, weakness, atrophy, and sarcopenia [ 67 , 68 ]. In addition, glucocorticoids coadministered during chemotherapy and deconditioning from hospitalization for cancer treatment lead to muscle loss that could also underpin decline in mobility [ 69 , 70 ]. These findings suggest that patients planning to receive autoHSCT may undergo a pretransplant mobility risk assessment to identify patients at the highest risk for falls and functional decline throughout their treatment trajectory. Moreover, pretransplant mobility assessment may allow clinical teams to prioritize limited rehabilitation expertise and resources for patients at the highest risk of functional decline and more extended hospital stays.
Symptoms may contribute to and co-occur with changes in mobility. Therefore, poorly controlled symptoms may help to identify patients at risk and those who may benefit from optimal symptom management and early palliative care integration [ 71 ]. We assessed multiple treatment-related symptoms previously associated with mobility and physical function in survivors of hematologic cancer [ 15 - 18 ]. In our sample, high nausea was significantly associated with great stride time variability and shallow heel strike angle. The pattern was also similar for pain, where high pain was significantly associated with slow gait speed, short stride length, great stride time variability, and less distance traveled. Persistent and severe nausea and pain clustering have been associated with poor performance status and limited physical function after cancer treatment [ 72 ]. Central nervous system disturbances owing to certain chemotherapies can affect cognition and movement, causing a sequela of symptoms comprising nausea and pain [ 73 ]. Chemotherapy can cause vestibular toxicity, resulting in nausea that intensifies over the transplant phase [ 74 , 75 ], which could directly or indirectly affect gait and balance [ 76 ]. Chronic pain is prevalent among survivors of hematologic cancer [ 77 ], has been associated with gait deficits in older adults [ 78 ], and is a significant risk factor for falls in survivors of cancer [ 79 ]. Persistent control of symptoms, including nausea and pain management, may be important for preserving physical functioning throughout the full treatment trajectory.
Integration of Wearable Inertial Sensors in Clinical Care
Providers subjectively assess a patient’s functional status before autoHSCT using the Karnofsky Performance Status assessment—a tool with good reliability and validity, but which is subjective and prone to clinician bias [ 80 - 82 ]. Until recently, characterizing mobility was only possible with complex and expensive laboratory-based systems, making it difficult to assess patients at the point of care. Introduction of wearable inertial sensors to assess mobility in the clinic setting widens the scope of what can be learned and implemented in clinical practice [ 83 ]. Mobility Lab is an affordable (comparable with other mobile gait assessment platforms) and time-effective approach to assess patients for aspects associated with risk for functional decline including postural sway, spatial and temporal components of gait, and dynamic balance during common movement such as turning [ 36 ]. The average time for an in-clinic assessment is 15 minutes, and it provides clinically relevant and accurate mobility evaluation that could be integrated into patient care and inform clinical decision-making.
Detecting dynamic and potentially reversible gait changes during pretransplant appointments may minimize future health care use by directing resources to patients at high risk of treatment-associated disability or falls. Interventions to promote physical activity and exercise before or during treatment would improve physical function and mobility [ 84 ]. Exercise is feasible and can safely be initiated after induction chemotherapy [ 85 ]. Exercise interventions before autoHSCT have shown to improve quality of life and functional capacity, as measured by the 6MWT [ 86 ]. Symptom management itself may also lead to increased activity level in patients, and exercise has also been used to manage chemotherapy-related symptoms [ 87 - 89 ].
Strengths and Limitations
A significant strength of our study was the use of wearable inertial sensors to obtain objective measures of mobility characteristics before autoHSCT. We were able to collect high-quality mobility data in the domains of turning, gait, and balance using wearable inertial sensors in a clinic setting, which may have future utility in patient care. Wearable inertial sensors have additional benefits including low cost and portability for assessment outside laboratory settings [ 90 ]. This study also has limitations. Our case-control analysis used a previously collected set of data on controls, causing the patient and control samples to be unbalanced on some characteristics such as sex and body composition (eg, height, weight, and BMI), which may influence mobility measures; thus, future studies should prospectively enroll a matched control cohort. Our sample size was modest for linear regression; thus, findings should be interpreted accordingly. We did not have access to data from previous induction chemotherapy (eg, chemotherapy drug or classification, dose, number of cycles, and weight change) and concurrent medication use (eg, antiemetics and pain medications); thus, we are limited in what can be inferred about symptoms assessed before transplant. Similarly, we did not collect data on physical activity levels, but it is possible that there may be interactions between symptoms, mobility, and physical activity. For example, patients with low symptom severity may be more physically active and therefore demonstrate better mobility. In contrast, patients experiencing nausea or pain may require increased need for rest, which negatively affects their mobility. Similarly, we did not have information about symptom management interventions that may have similar interactions. In addition, our cross-sectional analysis could not establish causality between gait characteristics and patient-reported chemotherapy-related symptoms. Thus, they may be co-occurring problems. However, it is possible that symptoms could serve as a surrogate indicator of developing mobility deficits. As the average time from induction chemotherapy to enrollment was approximately 3 weeks, patient-reported pretransplant symptoms may be related to chemotherapy or comorbidities. Future studies could better establish the temporality of symptom onset and progression regarding mobility using longitudinal serial assessment.
Conclusions
Patients with hematologic cancer who have completed induction chemotherapy experience multiple alterations in mobility, as detected by a system of wearable inertial sensors. These altered gait patterns, which may have resulted from cancer treatment, place older patients with hematologic cancer at an elevated fall risk [ 91 , 92 ], which could ultimately increase morbidity and mortality risk [ 93 , 94 ]. Patients experiencing great nausea and pain at the time of autoHSCT may be at high risk of experiencing mobility limitations during and after transplant. Although this study could not infer whether chemotherapy-related symptoms directly alter gait, the findings highlight distinct mobility deficits in patients, which could not have been easily identified using standard mobility tests alone. Patients experiencing symptoms may warrant a more thorough assessment of their mobility using wearable sensors by the clinical team, including rehabilitation specialists, during routine appointments before hospitalization. Understanding these relationships could improve preventive care, symptom management, and rehabilitation efforts by identifying patients scheduled for autoHSCT who are at risk for further functional decline or falls after induction chemotherapy.
The authors would like to acknowledge the time and effort of the study participants; the assistance of Oregon Health & Science University Knight Cancer Institute’s registered nurse coordinators; in particular, Malinda Burt, the statistical support of Sydnee Stoyles; and the contributions of Maddy Dunn and Ashley Lyons for participant recruitment and data collection. This study was supported by the National Institutes of Health National Cancer Institute Small Business Innovation Research Grant (HHSN261201600067C SBIR) and National Institutes of Health National Cancer Institute Center Core Grant (3 P30 CA069533-22S6) awarded to the Knight Cancer Institute.
Authors' Contributions: KWS, FH, and MEG contributed to the study design. KWS, MEG, and FH were involved in protocol development. CG was involved in participant recruitment and data collection. MBS and GH contributed to data analysis plan and execution. MBS, GH, FH, MEG, and KWS were involved in interpretation of results. MBS and KWS wrote the manuscript. GH, FH, MEG, CG, BHL, RS, and EJR edited the manuscript. MEG, FH, and KWS were involved in obtaining the funding. All the authors approved the final version of the manuscript.
Conflicts of Interest: MEG is an employee of APDM, Inc, and is required to complete training and disclosure regarding financial conflicts of interest before engaging in research conducted at Oregon Health & Science University. FH is a part-time employee and has significant financial interest in APDM, Inc. APDM, Inc may have commercial interest in the application of the results of this study. This potential conflict of interest has been reviewed and managed by Oregon Health & Science University.
Abbreviations
6-minute walk test
autologous hematopoietic stem cell transplant
hematopoietic stem cell transplant
minimally clinically important difference
Research Electronic Data Capture
Data Availability
The data that support the findings of this study are not publicly available owing to privacy or ethical reasons but may be provided from the corresponding author upon reasonable request. Restrictions apply to the availability of some data, which were used with permission of APDM, Inc for this study.
1 Siegel RL Miller KD Fuchs HE Jemal A Cancer statistics, 2022 CA Cancer J Clin 2022 01 72 1 7 33 10.3322/caac.21708 10.3322/caac.21708 35020204 35020204
2 Kennedy VE Olin RL Haematopoietic stem-cell transplantation in older adults: geriatric assessment, donor considerations, and optimisation of care Lancet Haematol 2021 11 8 11 e853 61 10.1016/S2352-3026(21)00231-3 34624239 S2352-3026(21)00231-3 34624239
3 Deshantri AK Varela Moreira A Ecker V Mandhane SN Schiffelers RM Buchner M Fens MH Nanomedicines for the treatment of hematological malignancies J Control Release 2018 10 10 287 194 215 10.1016/j.jconrel.2018.08.034 30165140 S0168-3659(18)30500-5 30165140
4 Murao M Hamada R Kondo T Miyasaka J Yoshida M Yonezawa H Arai Y Kanda J Nankaku M Ikeguchi R Takaori-Kondo A Matsuda S Analysis of factors associated with patient-reported physical functioning scores at discharge of allogeneic hematopoietic stem cell transplantation patients: a cross-sectional study Support Care Cancer 2021 12 29 12 7569 76 10.1007/s00520-021-06323-5 34120260 10.1007/s00520-021-06323-5 34120260
5 Lemieux C Ahmad I Bambace NM Bernard L Cohen S Delisle J Fleury I Kiss T Mollica L Roy D Sauvageau G Roy J Lachance S Evaluation of the impact of autologous hematopoietic stem cell transplantation on the quality of life of older patients with lymphoma Biol Blood Marrow Transplant 2020 01 26 1 157 61 10.1016/j.bbmt.2019.09.007 31521818 S1083-8791(19)30593-2 31521818
6 Nawas MT Sheng Y Huang C Andreadis C Martin TG Wolf JL Ai WZ Kaplan LD Mannis GN Logan AC Damon LE Olin RL Serial comprehensive geriatric and quality of life assessments in adults age ≥ 50 years undergoing autologous hematopoietic cell transplantation J Geriatr Oncol 2021 05 12 4 531 9 10.1016/j.jgo.2020.09.027 33059999 S1879-4068(20)30454-9 33059999
7 Morishita S Kaida K Aoki O Yamauchi S Wakasugi T Ikegame K Ogawa H Domen K Balance function in patients who had undergone allogeneic hematopoietic stem cell transplantation Gait Posture 2015 09 42 3 406 8 10.1016/j.gaitpost.2015.07.011 26233580 S0966-6362(15)00739-0 26233580
8 Rosko AE Huang Y Benson DM Efebera YA Hofmeister C Jaglowski S Devine S Bhatt G Wildes TM Dyko A Jones D Naughton MJ Byrd JC Burd CE Use of a comprehensive frailty assessment to predict morbidity in patients with multiple myeloma undergoing transplant J Geriatr Oncol 2019 05 10 3 479 85 10.1016/j.jgo.2018.05.015 29983352 S1879-4068(18)30157-7 29983352 PMC6320732
9 Nawas MT Andreadis C Martin TG Wolf JL Ai WZ Kaplan LD Mannis GN Logan AC Damon LE Huang C Olin RL Limitation in patient-reported function is associated with inferior survival in older adults undergoing autologous hematopoietic cell transplantation Biol Blood Marrow Transplant 2019 06 25 6 1218 24 10.1016/j.bbmt.2019.01.028 30708189 S1083-8791(19)30086-2 30708189
10 Beg MS Gupta A Stewart T Rethorst CD Promise of wearable physical activity monitors in oncology practice J Oncol Pract 2017 02 13 2 82 9 10.1200/JOP.2016.016857 28387544 28387544 PMC6075841
11 Gresham G Schrack J Gresham LM Shinde AM Hendifar AE Tuli R Rimel BJ Figlin R Meinert CL Piantadosi S Wearable activity monitors in oncology trials: current use of an emerging technology Contemp Clin Trials 2018 01 64 13 21 10.1016/j.cct.2017.11.002 29129704 S1551-7144(17)30473-1 29129704 PMC12004692
12 Beauchamp UL Pappot H Holländer-Mieritz C The use of wearables in clinical trials during cancer treatment: systematic review JMIR Mhealth Uhealth 2020 11 11 8 11 e22006 10.2196/22006 33174852 v8i11e22006 33174852 PMC7688381
13 Muhsen IN Rasheed OW Habib EA Alsaad RK Maghrabi MK Rahman MA Sicker D Wood WA Beg MS Sung AD Hashmi SK Current status and future perspectives on the Internet of Things in oncology Hematol Oncol Stem Cell Ther (forthcoming) 2021 10 18 10.1016/j.hemonc.2021.09.003 34687614 S1658-3876(21)00087-X 34687614
14 Zulu S Kenyon M Kenyon M Babic A Principles of conditioning therapy and cell infusion The European Blood and Marrow Transplantation Textbook for Nurses: Under the Auspices of EBMT 2018 Cham, Switzerland Springer 89 96 31314221
15 Magge RS DeAngelis LM The double-edged sword: neurotoxicity of chemotherapy Blood Rev 2015 03 29 2 93 100 10.1016/j.blre.2014.09.012 25445718 S0268-960X(14)00081-2 25445718 PMC5944623
16 Esser P Kuba K Scherwath A Johansen C Schwinn A Schirmer L Schulz-Kindermann F Kruse M Koch U Zander AR Kröger N Götze H Mehnert A Stability and priority of symptoms and symptom clusters among allogeneic HSCT patients within a 5-year longitudinal study J Pain Symptom Manage 2017 10 54 4 493 500 10.1016/j.jpainsymman.2017.07.012 28711754 S0885-3924(17)30275-0 28711754
17 Morishita S Kaida K Ikegame K Yoshihara S Taniguchi K Okada M Kodama N Ogawa H Domen K Impaired physiological function and health-related QOL in patients before hematopoietic stem-cell transplantation Support Care Cancer 2012 04 20 4 821 9 10.1007/s00520-011-1156-2 21479522 21479522
18 Wildes TM Fiala MA Falls in older adults with multiple myeloma Eur J Haematol 2018 03 100 3 273 8 10.1111/ejh.13009 29239009 29239009 PMC5814335
19 Bennett JA Winters-Stone K Nail L Conceptualizing and measuring physical functioning in cancer survivorship studies Oncol Nurs Forum 2006 01 01 33 1 41 9 10.1188/06.ONF.41-49 16470233 16470233
20 Winters-Stone KM Medysky ME Savin MA Patient-reported and objectively measured physical function in older breast cancer survivors and cancer-free controls J Geriatr Oncol 2019 03 10 2 311 6 10.1016/j.jgo.2018.10.006 30344000 S1879-4068(18)30209-1 30344000 PMC6409127
21 Horak F King L Mancini M Role of body-worn movement monitor technology for balance and gait rehabilitation Phys Ther 2015 03 95 3 461 70 10.2522/ptj.20140253 25504484 ptj.20140253 25504484 PMC4348720
22 Coulthard JT Treen TT Oates AR Lanovaz JL Evaluation of an inertial sensor system for analysis of timed-up-and-go under dual-task demands Gait Posture 2015 05 41 4 882 7 10.1016/j.gaitpost.2015.03.009 25827680 S0966-6362(15)00078-8 25827680
23 Ghislieri M Gastaldi L Pastorelli S Tadano S Agostini V Wearable inertial sensors to assess standing balance: a systematic review Sensors (Basel) 2019 09 20 19 19 4075 10.3390/s19194075 31547181 s19194075 31547181 PMC6806601
24 Kneis S Straub E Walz ID von Olshausen P Wehrle A Gollhofer A Bertz H Gait analysis of patients after allogeneic hematopoietic cell transplantation reveals impairments of functional performance Integr Cancer Ther 2020 19 1534735420915782 10.1177/1534735420915782 32368937 32368937 PMC7236089
25 Park JH Mancini M Carlson-Kuhta P Nutt JG Horak FB Quantifying effects of age on balance and gait with inertial sensors in community-dwelling healthy adults Exp Gerontol 2016 12 01 85 48 58 10.1016/j.exger.2016.09.018 27666186 S0531-5565(16)30375-8 27666186 PMC5101181
26 Fino PC Horak FB El-Gohary M Guidarelli C Medysky ME Nagle SJ Winters-Stone KM Postural sway, falls, and self-reported neuropathy in aging female cancer survivors Gait Posture 2019 03 69 136 42 10.1016/j.gaitpost.2019.01.025 30716669 S0966-6362(18)30729-X 30716669 PMC6579642
27 Groll DL To T Bombardier C Wright JG The development of a comorbidity index with physical function as the outcome J Clin Epidemiol 2005 06 58 6 595 602 10.1016/j.jclinepi.2004.10.018 15878473 S0895-4356(05)00021-1 15878473
28 Mancini M King L Salarian A Holmstrom L McNames J Horak FB Mobility lab to assess balance and gait with synchronized body-worn sensors J Bioeng Biomed Sci 2011 12 12 Suppl 1 007 10.4172/2155-9538.S1-007 24955286 PMC4062543 24955286
29 Salarian A Horak FB Zampieri C Carlson-Kuhta P Nutt JG Aminian K iTUG, a sensitive and reliable measure of mobility IEEE Trans Neural Syst Rehabil Eng 2010 06 18 3 303 10 10.1109/TNSRE.2010.2047606 20388604 20388604 PMC2922011
30 Mancini M Salarian A Carlson-Kuhta P Zampieri C King L Chiari L Horak FB ISway: a sensitive, valid and reliable measure of postural control J Neuroeng Rehabil 2012 08 22 9 59 10.1186/1743-0003-9-59 22913719 1743-0003-9-59 22913719 PMC3481400
31 Olsson LG Swedberg K Clark AL Witte KK Cleland JG Six minute corridor walk test as an outcome measure for the assessment of treatment in randomized, blinded intervention trials of chronic heart failure: a systematic review Eur Heart J 2005 04 26 8 778 93 10.1093/eurheartj/ehi162 15774495 ehi162 15774495
32 Burr JF Bredin SS Faktor MD Warburton DE The 6-minute walk test as a predictor of objectively measured aerobic fitness in healthy working-aged adults Phys Sportsmed 2011 05 39 2 133 9 10.3810/psm.2011.05.1904 21673494 21673494
33 Nordanstig J Broeren M Hensäter M Perlander A Osterberg K Jivegård L Six-minute walk test closely correlates to "real-life" outdoor walking capacity and quality of life in patients with intermittent claudication J Vasc Surg 2014 08 60 2 404 9 10.1016/j.jvs.2014.03.003 24690492 S0741-5214(14)00332-2 24690492
34 Steffen TM Hacker TA Mollinger L Age- and gender-related test performance in community-dwelling elderly people: six-minute walk test, berg balance scale, timed up and go test, and gait speeds Phys Ther 2002 02 82 2 128 37 10.1093/ptj/82.2.128 11856064 11856064
35 Simonsick EM Montgomery PS Newman AB Bauer DC Harris T Measuring fitness in healthy older adults: the Health ABC Long Distance Corridor Walk J Am Geriatr Soc 2001 11 49 11 1544 8 10.1046/j.1532-5415.2001.4911247.x 11890597 4911247 11890597
36 Mancini M Chiari L Holmstrom L Salarian A Horak FB Validity and reliability of an IMU-based method to detect APAs prior to gait initiation Gait Posture 2016 01 43 125 31 10.1016/j.gaitpost.2015.08.015 26433913 S0966-6362(15)00878-4 26433913 PMC4758510
37 Cabral KD Brech GC Alonso AC Soares AT Opaleye DC Greve JM Jacob-Filho W Posturographic measures did not improve the predictive power to identify recurrent falls in community-dwelling elderly fallers Clinics (Sao Paulo) 2020 4 3 75 e1409 10.6061/clinics/2020/e1409 32267394 S1807-5932(22)00282-4 32267394 PMC7100920
38 Wang K Lovell NH Del Rosario MB Liu Y Wang J Narayanan MR Brodie MA Delbaere K Menant J Lord SR Redmond SJ Inertial measurements of free-living activities: assessing mobility to predict falls Annu Int Conf IEEE Eng Med Biol Soc 2014 2014 6892 5 10.1109/EMBC.2014.6945212 25571580 25571580
39 Morris R Stuart S McBarron G Fino PC Mancini M Curtze C Validity of Mobility Lab (version 2) for gait assessment in young adults, older adults and Parkinson's disease Physiol Meas 2019 09 30 40 9 095003 10.1088/1361-6579/ab4023 31470423 31470423 PMC8072263
40 Harris PA Taylor R Thielke R Payne J Gonzalez N Conde JG Research electronic data capture (REDCap)--a metadata-driven methodology and workflow process for providing translational research informatics support J Biomed Inform 2009 04 42 2 377 81 10.1016/j.jbi.2008.08.010 18929686 S1532-0464(08)00122-6 18929686 PMC2700030
41 Cheng HL Lopez V Lam SC Leung AK Li YC Wong KH Au JS Sundar R Chan A De Ng TR Suen LK Chan CW Yorke J Molassiotis A Psychometric testing of the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) subscale in a longitudinal study of cancer patients treated with chemotherapy Health Qual Life Outcomes 2020 07 23 18 1 246 10.1186/s12955-020-01493-y 32703223 10.1186/s12955-020-01493-y 32703223 PMC7376939
42 Fayers PM Aaronson NK Bjordal K Sullivan M Curran D Bottomley A EORTC Quality of Life Group The EORTC QLQ-C30 Scoring Manual. 3rd edition European Organisation for Research and Treatment of Cancer 2001 2021-11-30 https://www.eortc.org/app/uploads/sites/2/2018/02/SCmanual.pdf
43 Raman S Ding K Chow E Meyer RM van der Linden YM Roos D Hartsell WF Hoskin P Wu JS Nabid A Haas R Wiggenraad R Babington S Demas WF Wilson CF Wong RK Zhu L Brundage M Minimal clinically important differences in the EORTC QLQ-C30 and brief pain inventory in patients undergoing re-irradiation for painful bone metastases Qual Life Res 2018 04 27 4 1089 98 10.1007/s11136-017-1745-8 29188483 10.1007/s11136-017-1745-8 29188483
44 Fredheim OM Borchgrevink PC Saltnes T Kaasa S Validation and comparison of the health-related quality-of-life instruments EORTC QLQ-C30 and SF-36 in assessment of patients with chronic nonmalignant pain J Pain Symptom Manage 2007 12 34 6 657 65 10.1016/j.jpainsymman.2007.01.011 17618079 S0885-3924(07)00422-8 17618079
45 Ameringer S Elswick Jr RK Menzies V Robins JL Starkweather A Walter J Gentry AE Jallo N Psychometric evaluation of the patient-reported outcomes measurement information system fatigue-short form across diverse populations Nurs Res 2016 65 4 279 89 10.1097/NNR.0000000000000162 27362514 00006199-201607000-00004 27362514 PMC4930004
46 Yost KJ Eton DT Garcia SF Cella D Minimally important differences were estimated for six Patient-Reported Outcomes Measurement Information System-Cancer scales in advanced-stage cancer patients J Clin Epidemiol 2011 05 64 5 507 16 10.1016/j.jclinepi.2010.11.018 21447427 S0895-4356(10)00431-2 21447427 PMC3076200
47 Kondo M Kiyomizu K Goto F Kitahara T Imai T Hashimoto M Shimogori H Ikezono T Nakayama M Watanabe N Akechi T Analysis of vestibular-balance symptoms according to symptom duration: dimensionality of the Vertigo Symptom Scale-short form Health Qual Life Outcomes 2015 01 22 13 4 10.1186/s12955-015-0207-7 25608680 s12955-015-0207-7 25608680 PMC4311503
48 Yardley L Donovan-Hall M Smith HE Walsh BM Mullee M Bronstein AM Effectiveness of primary care-based vestibular rehabilitation for chronic dizziness Ann Intern Med 2004 10 19 141 8 598 605 10.7326/0003-4819-141-8-200410190-00007 15492339 141/8/598 15492339
49 Radloff LS The CES-D scale: a self-report depression scale for research in the general population Appl Psychol Meas 1977 6 1 3 385 401 10.1177/014662167700100306
50 Haase I Winkeler M Imgart H Ascertaining minimal clinically meaningful changes in symptoms of depression rated by the 15-item Centre for Epidemiologic Studies Depression Scale J Eval Clin Pract 2022 06 28 3 500 6 10.1111/jep.13629 34647399 34647399
51 Cohen J Statistical Power Analysis for the Behavioral Sciences. 2nd edition 1988 Cambridge, MA, USA Academic press
52 Benjamini Y Hochberg Y Controlling the false discovery rate: a practical and powerful approach to multiple testing J R Stat Soc Series B Stat Methodol 1995 57 1 289 300 10.1111/j.2517-6161.1995.tb02031.x
53 Winters-Stone KM Horak F Jacobs PG Trubowitz P Dieckmann NF Stoyles S Faithfull S Falls, functioning, and disability among women with persistent symptoms of chemotherapy-induced peripheral neuropathy J Clin Oncol 2017 08 10 35 23 2604 12 10.1200/JCO.2016.71.3552 28586243 28586243 PMC5549452
54 Campbell G Wolfe RA Klem ML Risk factors for falls in adult cancer survivors: an integrative review Rehabil Nurs 2018 43 4 201 13 10.1097/rnj.0000000000000173 29957697 00006939-201807000-00004 29957697 PMC6029723
55 Middleton A Fritz SL Lusardi M Walking speed: the functional vital sign J Aging Phys Act 2015 04 23 2 314 22 10.1123/japa.2013-0236 24812254 2013-0236 24812254 PMC4254896
56 Fang X Liu C Jiang Z Reference values of gait using APDM movement monitoring inertial sensor system R Soc Open Sci 2018 01 5 1 170818 10.1098/rsos.170818 29410801 rsos170818 29410801 PMC5792878
57 Guida JL Ahles TA Belsky D Campisi J Cohen HJ DeGregori J Fuldner R Ferrucci L Gallicchio L Gavrilov L Gavrilova N Green PA Jhappan C Kohanski R Krull K Mandelblatt J Ness KK O'Mara A Price N Schrack J Studenski S Theou O Tracy RP Hurria A Measuring aging and identifying aging phenotypes in cancer survivors J Natl Cancer Inst 2019 12 01 111 12 1245 54 10.1093/jnci/djz136 31321426 5535600 31321426 PMC7962788
58 Liu MA DuMontier C Murillo A Hshieh TT Bean JF Soiffer RJ Stone RM Abel GA Driver JA Gait speed, grip strength, and clinical outcomes in older patients with hematologic malignancies Blood 2019 07 25 134 4 374 82 10.1182/blood.2019000758 31167800 S0006-4971(20)42385-7 31167800 PMC6659254
59 Leach JM Mellone S Palumbo P Bandinelli S Chiari L Natural turn measures predict recurrent falls in community-dwelling older adults: a longitudinal cohort study Sci Rep 2018 03 12 8 1 4316 10.1038/s41598-018-22492-6 10.1038/s41598-018-22492-6 29531284 10.1038/s41598-018-22492-6 29531284 PMC5847590
60 Verghese J Holtzer R Lipton RB Wang C Quantitative gait markers and incident fall risk in older adults J Gerontol A Biol Sci Med Sci 2009 08 64 8 896 901 10.1093/gerona/glp033 19349593 glp033 19349593 PMC2709543
61 Dulaney CR McDonald AM Wallace AS Fiveash J Gait speed and survival in patients with brain metastases J Pain Symptom Manage 2017 07 54 1 105 9 10.1016/j.jpainsymman.2017.03.013 28479417 S0885-3924(17)30179-3 28479417
62 Monfort SM Pan X Patrick R Ramaswamy B Wesolowski R Naughton MJ Loprinzi CL Chaudhari AM Lustberg MB Gait, balance, and patient-reported outcomes during taxane-based chemotherapy in early-stage breast cancer patients Breast Cancer Res Treat 2017 07 164 1 69 77 10.1007/s10549-017-4230-8 28374323 10.1007/s10549-017-4230-8 28374323 PMC5510549
63 Peterka RJ Sensory integration for human balance control Handb Clin Neurol 2018 159 27 42 10.1016/B978-0-444-63916-5.00002-1 30482320 B978-0-444-63916-5.00002-1 30482320
64 Wampler MA Topp KS Miaskowski C Byl NN Rugo HS Hamel K Quantitative and clinical description of postural instability in women with breast cancer treated with taxane chemotherapy Arch Phys Med Rehabil 2007 08 88 8 1002 8 10.1016/j.apmr.2007.05.007 17678662 S0003-9993(07)00350-4 17678662
65 Schmitt AC Repka CP Heise GD Challis JH Smith JD Comparison of posture and balance in cancer survivors and age-matched controls Clin Biomech (Bristol, Avon) 2017 12 50 1 6 10.1016/j.clinbiomech.2017.09.010 28968535 S0268-0033(17)30204-8 28968535
66 Maki BE Holliday PJ Topper AK A prospective study of postural balance and risk of falling in an ambulatory and independent elderly population J Gerontol 1994 03 49 2 M72 84 10.1093/geronj/49.2.m72 8126355 8126355
67 Diaz M Schiff D Ahluwalia M Metellus P Soffietti R Neurological complications of chemotherapy Central Nervous System Metastases 2020 Cham, Switzerland Springer 329 40
68 Knobf MT Winters-Stone K Exercise and cancer Annu Rev Nurs Res 2013 31 327 65 10.1891/0739-6686.31.327 24894145 24894145
69 Murnane A Keogh J Magat F Imbesi S Coulombe M Patchell S Abbott A The impact of an inpatient hospital admission on patients’ physical functioning and quality of life in the oncology setting J Nurs Educ Pract 2015 04 28 5 7 75 82 10.5430/jnep.v5n7p75
70 Wang DX Yao J Zirek Y Reijnierse EM Maier AB Muscle mass, strength, and physical performance predicting activities of daily living: a meta-analysis J Cachexia Sarcopenia Muscle 2020 02 11 1 3 25 10.1002/jcsm.12502 31788969 31788969 PMC7015244
71 El-Jawahri A LeBlanc T VanDusen H Traeger L Greer JA Pirl WF Jackson VA Telles J Rhodes A Spitzer TR McAfee S Chen YA Lee SS Temel JS Effect of inpatient palliative care on quality of life 2 weeks after hematopoietic stem cell transplantation: a randomized clinical trial JAMA 2016 11 22 316 20 2094 103 10.1001/jama.2016.16786 27893130 2585978 27893130 PMC5421101
72 Ferreira KA Kimura M Teixeira MJ Mendoza TR da Nóbrega JC Graziani SR Takagaki TY Impact of cancer-related symptom synergisms on health-related quality of life and performance status J Pain Symptom Manage 2008 06 35 6 604 16 10.1016/j.jpainsymman.2007.07.010 18362059 S0885-3924(08)00055-9 18362059
73 Stone JB DeAngelis LM Cancer-treatment-induced neurotoxicity--focus on newer treatments Nat Rev Clin Oncol 2016 02 13 2 92 105 10.1038/nrclinonc.2015.152 26391778 nrclinonc.2015.152 26391778 PMC4979320
74 Prayuenyong P Taylor JA Pearson SE Gomez R Patel PM Hall DA Kasbekar AV Baguley DM Vestibulotoxicity associated with platinum-based chemotherapy in survivors of cancer: a scoping review Front Oncol 2018 9 25 8 363 10.3389/fonc.2018.00363 30319960 30319960 PMC6167545
75 Anderson LJ Yin C Burciaga R Lee J Crabtree S Migula D Geiss-Wessel K Liu HM Graf SA Chauncey TR Garcia JM Assessing cachexia acutely after autologous stem cell transplant Cancers (Basel) 2019 09 04 11 9 1300 10.3390/cancers11091300 31487803 cancers11091300 31487803 PMC6769803
76 Winters-Stone KM Torgrimson B Horak F Eisner A Nail L Leo MC Chui S Luoh S Identifying factors associated with falls in postmenopausal breast cancer survivors: a multi-disciplinary approach Arch Phys Med Rehabil 2011 04 92 4 646 52 10.1016/j.apmr.2010.10.039 21367394 S0003-9993(10)00884-1 21367394 PMC3430739
77 Ma JD El-Jawahri AR LeBlanc TW Roeland EJ Pain syndromes and management in adult hematopoietic stem cell transplantation Hematol Oncol Clin North Am 2018 06 32 3 551 67 10.1016/j.hoc.2018.01.012 29729788 S0889-8588(18)30022-4 29729788
78 Ogawa EF Shi L Bean JF Hausdorff JM Dong Z Manor B McLean RR Leveille SG Chronic pain characteristics and gait in older adults: the MOBILIZE Boston study II Arch Phys Med Rehabil 2020 03 101 3 418 25 10.1016/j.apmr.2019.09.010 31634443 S0003-9993(19)31306-1 31634443 PMC7050337
79 Spoelstra S Given B von Eye A Given C Falls in the community-dwelling elderly with a history of cancer Cancer Nurs 2010 33 2 149 55 10.1097/NCC.0b013e3181bbbe8a 20142742 20142742 PMC4471335
80 Schag CC Heinrich RL Ganz PA Karnofsky performance status revisited: reliability, validity, and guidelines J Clin Oncol 1984 03 2 3 187 93 10.1200/JCO.1984.2.3.187 6699671 6699671
81 Oken MM Creech RH Tormey DC Horton J Davis TE McFadden ET Carbone PP Toxicity and response criteria of the Eastern Cooperative Oncology Group Am J Clin Oncol 1982 12 5 6 649 55 7165009 7165009
82 Kelly CM Shahrokni A Moving beyond Karnofsky and ECOG performance status assessments with new technologies J Oncol 2016 2016 6186543 10.1155/2016/6186543 10.1155/2016/6186543 27066075 27066075 PMC4811104
83 Gresham G Hendifar AE Spiegel B Neeman E Tuli R Rimel BJ Figlin RA Meinert CL Piantadosi S Shinde AM Wearable activity monitors to assess performance status and predict clinical outcomes in advanced cancer patients NPJ Digit Med 2018 7 5 1 27 10.1038/s41746-018-0032-6 10.1038/s41746-018-0032-6 31304309 32 31304309 PMC6550281
84 Stout NL Fu JB Silver JK Prehabilitation is the gateway to better functional outcomes for individuals with cancer J Cancer Rehabil 2021 4 283 6 35048084 35048084 PMC8765744
85 Paul KL Rehabilitation and exercise considerations in hematologic malignancies Am J Phys Med Rehabil 2011 05 90 5 Suppl 1 S88 94 10.1097/PHM.0b013e31820be055 21765268 00002060-201105001-00010 21765268
86 Prins MC van Hinte G Koenders N Rondel AL Blijlevens NM van den Berg MG The effect of exercise and nutrition interventions on physical functioning in patients undergoing haematopoietic stem cell transplantation: a systematic review and meta-analysis Support Care Cancer 2021 11 29 11 7111 26 10.1007/s00520-021-06334-2 34131848 10.1007/s00520-021-06334-2 34131848 PMC8464580
87 Hunter EG Gibson RW Arbesman M D'Amico M Systematic review of occupational therapy and adult cancer rehabilitation: Part 1. Impact of physical activity and symptom management interventions Am J Occup Ther 2017 71 2 7102100030p1 11 10.5014/ajot.2017.023564 28218585 28218585
88 Campbell KL Winters-Stone KM Wiskemann J May AM Schwartz AL Courneya KS Zucker DS Matthews CE Ligibel JA Gerber LH Morris GS Patel AV Hue TF Perna FM Schmitz KH Exercise guidelines for cancer survivors: consensus statement from international multidisciplinary roundtable Med Sci Sports Exerc 2019 11 51 11 2375 90 10.1249/MSS.0000000000002116 31626055 00005768-201911000-00023 31626055 PMC8576825
89 Winters-Stone KM Moe EL Perry CK Medysky M Pommier R Vetto J Naik A Enhancing an oncologist's recommendation to exercise to manage fatigue levels in breast cancer patients: a randomized controlled trial Support Care Cancer 2018 03 26 3 905 12 10.1007/s00520-017-3909-z 28965138 10.1007/s00520-017-3909-z 28965138
90 Najafi B Khan T Wrobel J Laboratory in a box: wearable sensors and its advantages for gait analysis Annu Int Conf IEEE Eng Med Biol Soc 2011 2011 6507 10 10.1109/IEMBS.2011.6091605 22255829 22255829
91 Harrington CB Hansen JA Moskowitz M Todd BL Feuerstein M It's not over when it's over: long-term symptoms in cancer survivors--a systematic review Int J Psychiatry Med 2010 40 2 163 81 10.2190/PM.40.2.c 20848873 20848873
92 Ness KK Wogksch MD Frailty and aging in cancer survivors Transl Res 2020 07 221 65 82 10.1016/j.trsl.2020.03.013 32360946 S1931-5244(20)30063-3 32360946 PMC7321876
93 Sattar S Haase K Kuster S Puts M Spoelstra S Bradley C Wildes TM Alibhai S Falls in older adults with cancer: an updated systematic review of prevalence, injurious falls, and impact on cancer treatment Support Care Cancer 2021 01 29 1 21 33 10.1007/s00520-020-05619-2 32671565 10.1007/s00520-020-05619-2 32671565
94 Toomey A Friedman L Mortality in cancer patients after a fall-related injury: the impact of cancer spread and type Injury 2014 11 45 11 1710 6 10.1016/j.injury.2014.03.008 24745652 S0020-1383(14)00132-6 24745652