Does testing of brainstem auditory response aid diagnosis in progressive spastic paraparesis?

40 patients with progressive spastic paraparesis of uncertain cause were studied in order to assess the outcome of their investigations. Abnormalities of the visual evoked response (VER) were found in 33%, indicating a second lesion in the nervous system. An additional 15% had abnormalities of the brainstem auditory evoked potentials (BAEP), indicating an supra-spinal, though not necessarily a second lesion. Qualitative CSF examinations for oligoclonal IgG banding showed abnormality in 30%, and considerable overlap (83%) with the patients who had abnormal VER, but not in those with an abnormal BAEP alone. It is concluded that the BAEP is of value when the VER and CSF are normal.