Trajectory of Mobility Function Decline for People With Motor Neuron Disease.

OBJECTIVES

The primary aim of this study was to explore factors that may influence the rate of mobility function decline. A secondary aim was to identify the impact of neck weakness on mobility decline in people living with motor neuron disease (MND).

DESIGN

Retrospective, longitudinal observational study design.

SETTING

This study was conducted at a Statewide Progressive Neurological Disease Service (SPNDS) in inpatients, outpatients, and community-based services. The SPNDS clinic treats adults with MND from both metropolitan and rural settings.

PARTICIPANTS

Adults with MND attending the SPNDS were recruited to participate in the study.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Categorical data relating to mobility function (walking endurance, gait aid used, and level of assistance required) were recorded. Neck weakness was measured as present or absent based on the participant's subjective report and/or objective observation of head position when upright.

RESULTS

Results from the 358 participants recruited showed that the median time to loss of independent gait was 30.5 months (range, 4-239; interquartile range [IQR], 26), full-time wheelchair use was 34 months (IQR, 35; range, 5-238), and median time to becoming housebound was 28 months from MND symptom onset (IQR, 24.5; range, 5-219 mo). A total of 141 (39.4%) participants had neck weakness. The presence of neck weakness resulted in earlier loss of independent gait and quicker to become housebound. There was no significant difference in time to full-time wheelchair use between participants with or without neck weakness.

CONCLUSIONS

There was an effect of both phenotype and neck weakness on the trajectory of mobility function decline in people with MND. Overall, people with amyotrophic lateral sclerosis phenotype (bulbar, cervical, or lumbar onset) experienced a more rapid rate of decline in mobility function than those with flail limb and primary lateral sclerosis phenotypes. In addition, those demonstrating neck weakness were quicker to decline in mobility than those without neck weakness.