Long-term potentiation-like plasticity is retained during relapse in patients with Multiple Sclerosis

Carolin Balloff; Sveva Novello; Arved-Sebastian Stucke; Lisa Kathleen Janssen; Elisa Heinen; Christian Johannes Hartmann; Sven Günther Meuth; Alfons Schnitzler; Iris-Katharina Penner; Philipp Albrecht; Stefan Jun Groiss

doi:10.1016/j.clinph.2023.07.013

Long-term potentiation-like plasticity is retained during relapse in patients with Multiple Sclerosis

Clin Neurophysiol. 2023 Nov:155:76-85. doi: 10.1016/j.clinph.2023.07.013. Epub 2023 Aug 29.

Affiliations

¹ Department of Neurology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany; Department of Neurology, Kliniken Maria Hilf GmbH, 41063 Moenchengladbach, Germany.
² Department of Neurology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany.
³ Department of Neurology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany; Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany.
⁴ Department of Neurology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany; Department of Neurology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland.
⁵ Department of Neurology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany; Department of Neurology, Kliniken Maria Hilf GmbH, 41063 Moenchengladbach, Germany. Electronic address: philipp.albrecht@mariahilf.de.
⁶ Department of Neurology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany; Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany; Neurocenter Duesseldorf, 40211 Duesseldorf, Germany.

PMID: 37776674
DOI: 10.1016/j.clinph.2023.07.013

Abstract

Objective: To investigate the degree of synaptic plasticity in Multiple Sclerosis (MS) patients during acute relapses compared to stable MS patients and healthy controls (HCs) and to analyze its functional relevance.

Methods: Facilitatory quadripulse stimulation (QPS) was applied to the primary motor cortex in 18 acute relapsing and 18 stable MS patients, as well as 18 HCs. The degree of synaptic plasticity was measured by the change in motor evoked potential amplitude following QPS. Symptom recovery was assessed three months after relapse.

Results: Synaptic plasticity was induced in all groups. The degree of induced plasticity did not differ between acute relapsing patients, HCs, and stable MS patients. Plasticity was significantly higher in relapsing patients with motor disability compared to relapsing patients without motor disability. In most patients (n = 9, 50%) symptoms had at least partially recovered three months after the relapse, impeding meaningful analysis of the functional relevance of baseline synaptic plasticity.

Conclusions: QPS-induced synaptic plasticity is retained during acute MS relapses. Subgroup analyses suggest that stabilizing metaplastic mechanisms may be more important to prevent motor disability but its functional relevance needs to be verified in larger, longitudinal studies.

Significance: New insights into synaptic plasticity during MS relapses are provided.

Keywords: Multiple Sclerosis; Quadripulse stimulation; Relapse; Repetitive transcranial magnetic stimulation; Synaptic plasticity.