Short-latency somatosensory-evoked potentials demonstrate cortical dysfunction in patients with Angelman syndrome

Kiyoshi Egawa; Shinji Saitoh; Naoko Asahina; Hideaki Shiraishi

doi:10.1016/j.ensci.2020.100298

Short-latency somatosensory-evoked potentials demonstrate cortical dysfunction in patients with Angelman syndrome

eNeurologicalSci. 2020 Dec 1:22:100298. doi: 10.1016/j.ensci.2020.100298. eCollection 2021 Mar.

Authors

Kiyoshi Egawa¹, Shinji Saitoh², Naoko Asahina¹, Hideaki Shiraishi¹

Affiliations

¹ Department of Pediatrics, Hokkaido University Graduate School of Medicine, North 15 West 7, Kita-ku, Sapporo 060-8638, Japan.
² Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho -ku, Nagoya 467-8601, Japan.

Abstract

Background: Angelman syndrome (AS) is neurodevelopmental disorder, causal gene of which is maternally expressed UBE3A. A majority of patients results from the large deletion of relevant chromosome which includes GABA_A receptor subunit genes (GABARs) as well as UBE3A (AS Del). We previously reported aberrantly desynchronized primary somatosensory response in AS Del by using magnetoencephalography. The purpose of this study is to estimate cortical and subcortical involvement in the deficit of primary somatosensory processing in AS.

Methods: We analyzed short-latency somatosensory-evoked potentials (SSEPs) in 8 patients with AS Del. SSEPs were recorded on a 4-channel system comprising of two cortical electrodes which were placed on the frontal and centro-parietal areas. The peak and onset latency of each component were measured to compare latency and interval times.

Results: The first-cortical peak latency (N20, P20), and N13-N20 peak interval times were significantly prolonged in AS Del compared to healthy controls. In contrast, there was no difference in latencies between subcortical components up to N20 onset or for N11-N20 onset interval times.

Conclusion: Highly desynchronized first-cortical SSEP components and normal latencies of subcortical components indicated cortical dysfunction rather than impairment of afferent pathways in AS Del patients, which might be attributed to GABAergic dysfunction due to loss of UBE3A function and heterozygosity of GABARs.

Keywords: AS Del, AS patients with a deletion in 15q11-q13; AS, Angelman syndrome; Angelman syndrome; CCT, Central conduction time; CZP, Clonazepam; GABARs, GABAA receptor subunit genes; GABAergic systems; Neurodevelopmental disorders; SEFs, Somatosensory-evoked fields; SSEPs, Short-latency somatosensory-evoked potentials; Somatosensory-evoked potentials; VPA, Valproic acid.