Trajectory of Mobility Fuction Decline for People with Motor Neuron Disease.

Abstract

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). Retrospective, longitudinal observational study design. This study was undertaken at a State-wide Progressive Neurological Disease Service (SPNDS) in the inpatients, outpatients and community-based services. The SPNDS clinic treats adults with MND from both metropolitan and rural settings. Adults with motor neuron disease attending the Statewide Progressive Neurological Disease Service were recruited to participate in the study. Not applicable. categorical data relating to mobility function (walking endurance, gait aid used and level of assistance required) was recorded. Neck weakness was measured as present or absent based on participant subjective report and/or objective observation of head position when upright. Results from the 358 participants recruited showed that the median time to loss of independent gait was 30.5 months (range 4-239; 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 months). 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. 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 (ALS) 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 (PLS) phenotypes. Additionally, those demonstrating neck weakness were quicker to decline in mobility than those without neck weakness.