Spinal bulbar muscular atrophy (SBMA) causes a loss of motor neurons in the spinal cord and brainstem. It mainly affects facial and swallowing muscles and the muscles in the arms and legs.

The failure of this system in ALS may translate into the split hand presentation, gait disturbance, split leg syndrome and bulbar symptomatology related to vocalisation and breathing, and possibly ...

We have noted that a subgroup of patients with classic ALS present with progressive wasting and weakness of the arms, with little or no functional impairment of the bulbar muscles ...