Extrapyramidal involvement in amyotrophic lateral sclerosis: backward falls and retropulsion

Three patients with sporadic amyotrophic lateral sclerosis (ALS) presented with a history of backward falls. Impaired postural reflexes and retropulsi on accompanied clinical features of ALS. Hypokinesia, decreased arm swing, and a positive glabellar tap were noted in two of these three patients. Cog nitive impairment, tremor, axial rigidity, sphincter dysfunction, nuchal dy stonia, dysautonomia, and oculomotor dysfunction were absent. Brain MRI dis closed bilateral T2 weighted hyperintensities in the internal capsule and g lobus pallidus in one patient. Necropsy studies performed late in the cours e of ALS have shown degeneration in extrapyramidal sites-for example, the g lobus pallidus, thalamus, and substantia nigra. Clinically, backward falls and retropulsion may occur early in ALS. This may reflect extrapyramidal in volvement.