Rigid spine syndrome: vacuolar variant multimodal evoked potentials

Overt or covert central nervous system (CNS) abnormalities have been reported in various primary muscle diseases, including congenital muscular dystrophies.

To ascertain by neurophysiologic techniques evidence of CNS dysfunction in a relatively large, homogeneous group of patients with the "vacuolar variant" of the rigid spine syndrome (RSS).

Standard evoked potential (EP) techniques were used to study the visual, auditory and somatosensory pathways in patients with RSS.

Abnormal values were recorded in 78% (7/9) of patients, specifically of visual pathways (2/9), brainstem auditory pathways (2/9), and somatosensory pathways (5/9), and the retina (1/9). Abnormal findings were not correlated with clinical measures of patient age, disease duration nor degree of weakness.

Electrophysiological studies showed that the CNS is not primarily involved in any disease process that underlies this congenital myopathy. There were reasonable other explanations for most abnormal measurements.