Differences in evoked potential characteristics between DRPLA patients andpatients with progressive myoclonic epilepsy: preliminary findings indicating usefulness for differential diagnosis

Kasai, K Onuma, T Kato, M Kato, T Takeya, J Sekimoto, M Watanabe, K Minami, N Goto, Y Minabe, Y

K. Kasai et al., Differences in evoked potential characteristics between DRPLA patients andpatients with progressive myoclonic epilepsy: preliminary findings indicating usefulness for differential diagnosis, EPILEPSY R, 37(1), 1999, pp. 3-11

20

INGLESE

Article

Neurology,"Neurosciences & Behavoir

EPILEPSY RESEARCH

0920-1211 → ACNP

37

1

1999

3 - 11

ISI

0920-1211(199910)37:1<3:DIEPCB>2.0.ZU;2-0

The characteristics of evoked potentials in patients with dentatorubral-pal lidoluysian atrophy (DRPLA) were investigated. Twelve patients with DRPLA a nd three patients with progressive myoclonic epilepsy (PME) attributable to other causes participated in the study. In 11 out of the 12 patients, the diagnosis of DRPLA was genetically confirmed, based on a 56-75 CAG triplet repeat expansion on chromosome 12p; in the remaining patient, the diagnosis was not genetically confirmed but the patient was clinically diagnosed as having DRPLA and was within the same pedigree as one of the 11 genetically confirmed patients. Two out of the three patients with PME, who had been te sted for dodecamer repeat expansion in the cystatin B gene, were geneticall y confirmed as having Unverricht-Lundborg disease (UL); the remaining patie nt was also clinically diagnosed as having UL, but the patient did not have the aforementioned genetic abnormality. Somatosensory evoked potentials (S EPs) and brainstem auditory evoked responses (BAERs) were recorded. The amp litudes of the SEPs were determined as the peak-to-peak amplitudes between P2 and N2 deflections. The results revealed that high-amplitude SEPs were n ot evoked in any of the DRPLA patients; on the other hand, high-amplitude S EPs were evoked in all the patients with UL. Moreover, BAERs were absent in seven out of the 12 patients with DRPLA, on the other hand, all UL patient s showed BAERs in which all peaks, from I to V, were distinguishable. These results suggest differences in pathophysiology between DRPLA, which predom inantly affects the brainstem and subcortical regions, and PME, characteriz ed by cortical hyperexcitability. Thus, evoked potential measurements may b e useful to differentiate DRPLA patients from these with progressive myoclo nic epilepsy. (C) 1999 Elsevier Science B.V. All rights reserved.