Gait apraxia in multiple sclerosis

Background: Gait apraxia is a gait disorder not attributable to motor, cerebellar, or sensory dysfunction. Gait impairment is common in Multiple Sclerosis (MS), but is mostly attributed to spasticity and ataxia. Impairment ratings scales are designed accordingly and do not separately evaluate apraxia. Objective: To describe 15 patients with gait apraxia resulting from MS as their major functional impairment. Methods: The Mayo Clinic database (1994-2007) was searched for the terms MS and gait apraxia. Inclusion criteria: Definite MS, significant gait apraxia. Exclusion criteria: alternative disorder causing apraxia, predominantly spastic/ataxic gait disorder. Results: 9 (60%) of the patients were women, and 12 (80%) had a progressive MS course. Gait apraxia was evident at a median of 8 years (range 0-34) following MS onset. Median EDSS at recognition of gait apraxia was 6.5 (range 5-8). Cognitive dysfunction was present in 11 (73%) and neurogenic bladder dysfunction in 14 (93%). The commonest MRI findings were confluent periventricular T2 lesions, T1 hypointensity and generalized cerebral atrophy with symmetrical ex vacuo ventricular enlargement. Conclusion: Gait apraxia can cause significant functional impairment in MS patients, and may be underrecognized. The natural course of the neurological deficit in such patients is unknown, and may differ from that of MS patients with other ambulatory disabilities.