Visual and somatosensory evoked potentials in vitamin E deficiency with cystic fibrosis.

Patients with cystic fibrosis (CF) and pancreatic malabsorption frequently have vitamin E deficiency. Affected patients may develop spinocerebellar degeneration with dysarthria, ataxia, proximal weakness, proprioceptive loss and areflexia. Of a highly selected group of 10 patients with vitamin E levels below 5 micrograms/ml (normal 5-20 micrograms/ml), 7 had abnormal neurological examinations, predominantly affecting vibration and joint position perception with some severely affected patients manifesting diminished visual acuity, tremor, ataxia and diffuse weakness. Evoked potential studies showed marked abnormalities in 3 patients, demonstrating deficits in the optic pathways and in the cervical cord dorsal column pathways. Evoked potential studies may supplement careful neurological examination in patients with CF before and after supplementation with vitamin E to evaluate their progression and response to treatment.