[Short somatosensory evoked potentials in patients with Fukuyama type congenital muscular dystrophy--a comparison with CT and MRI findings].

Seven patients with Fukuyama type congenital muscular dystrophy were studied. Low density areas (LDs) in the cerebral white matter on cranial CT were present in all 4 patients younger than 13 years of age and in 1 of 3 adult patients. LDs corresponded to low signals on T1 weighted MRI image and high signals on T2 weighted MRI image. The follow-up MRI showed a decreased tendency of the abnormal signals in 2 patients. Short somatosensory evoked potentials (SSEPs) in two infants, aged 4 months and 8 months, showed absent or depressed N1 amplitudes and delayed interpeak latencies from P3 to N1. N1 amplitudes increased on follow-up studies. SSEPs of five patients, who were older than 2 years of age, showed normal N1-P3 latencies. Amplitude of N1 was low in 2 patients with LD. Since the absent or depressed amplitude and delayed latency of N1 improved with the decrease of abnormal signals on MRI, we considered that N1 abnormalities show delayed myelination.