Postural adjustments during activities of daily living with an upper limb prosthesis.

BACKGROUND

People with upper limb difference (ULD) using prostheses often use compensatory trunk movements to perform activities of daily living (ADL). Compensatory movements may provide additional challenges for the postural control system to maintain balance. However, no prior studies have quantified postural adjustments during ADLs in this population. The purpose of this study was to determine if upper limb prosthesis users make larger postural adjustments during ADLs compared to people without ULD.

METHODS

Nine individuals with ULD and nine without ULD performed unimanual and bimanual ADLs. Participants with ULD wore their prescribed body-powered or myoelectric prostheses. For each ADL, postural adjustments derived from center of pressure (CoP) position were compared across limbs (control, prosthetic, and intact). The impact of additional factors including prosthetic type, etiology, and duration of prosthetic use was also explored.

FINDINGS: When using only the prosthesis or using it asymmetrically to the intact limb, people with ULD had larger CoP motion than people without ULD (p < 0.012). Exploratory comparisons found that during tasks that required grasping larger objects, body-powered prosthesis users and people with acquired amputation had larger CoP motion than myoelectric prosthesis users and people with congenital limb difference, respectively (g > 0.642). When performing a bimanual symmetric task, people who had owned their prosthesis longer had less CoP motion (p = 0.032).

INTERPRETATION: Overall, the study demonstrates that individuals with ULD make larger postural adjustments when performing ADLs that incorporate their prosthesis. The extent of these differences is affected by prosthesis type, limb difference etiology, and duration of prosthesis ownership.