Transcranial magnetic stimulation in an adrenoleukodystrophy patient

We experienced an 11-year-old boy diagnosed as having adrenoleukodystrophy (ALD), and studied his motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS). He had intellectual and visual impairment, and MRI revealed high intensity of the parieto-occipital white matter. On evaluation of the long tracts, slight spasticity with equivocal Babinski signs was noted: however, the long tracts appeared intact on MRI, and short latency somatosensory evoked potentials (SSEPs) were completely normal. On TMS delivered through a circular coil, MEPs recorded from the relaxed first dorsal interosseous muscle showed that only the duration was significantly prolonged, which may be due to temporal dispersion of descending volleys in the pyramidal tracts, while the latency was not prolonged. TMS in ALD was considered sensitive and useful for detecting subtle involvement of the long tracts.