Electrophysiological characterization of the X-linked recessive bulbospinal neuronopathy (XRBSN).

Detailed electrophysiological analyses including nerve conduction velocity measurements of motor and sensory nerves, EMG recordings of a variety of muscles, evoked potentials, magnetic brain stimulation, electrophysiological testing of autonomic functions, tremor measurements and testing of voluntary movements were applied to three patients with X-linked recessive bulbospinal neuronopathy (XRBSN). All three patients presented with a slowly progressive anterior horn impairment, involvement of sensory nerves and posterior columns, but intact central descending motor pathways and an essential tremor responding to propranolol treatment. The spectrum of electrophysiological findings helps to diagnose XRBSN reliably even in sporadic cases.