Could neurophysiological measures help in understanding alexithymia in multiple sclerosis?

Abstract

Objectives Patients with multiple sclerosis (MS) could have deficits in emotional processing. Among the latter, alexithymia could affect up to 53% of this population [2] ; it is a multicomponent personality construct that entails an operative thinking and difficulties in understanding and analyzing one's own feelings. Previous transcranial magnetic stimulation (TMS) studies have suggested aberrant interhemispheric transfer and GABAergic transmission behind alexithymia [3] , but none was performed in the context of MS. Methods Right-handed MS patients were enrolled if they had no contraindications to TMS. The Toronto Alexithymia Scale (TAS) classified patients as alexithymic (score > 55) and non-alexithymic. Socio-demographic, clinical and neuropsychological data were collected. The following TMS measures were obtained [1] : resting motor threshold, interhemispheric inhibition (interstimuli interval: 8, 10 and 12 ms) and cortical silent period (CSP). The statistical analysis consisted of group comparison (alexithymic versus non-alexithymic) of socio-demographic, clinical and neuropsychological measures and correlation analysis (corrections with False Discovery Rate approach) between TAS scores and TMS measures. Results Twenty-two patients completed the study (n = 10 alexithymic and n = 12 non-alexithymic). Patients did not significantly differ with regard to socio-demographic, clinical or neuropsychological data. A significantly shorter CSP duration was observed among alexithymic patients (mean: 84.34 ± 49.73) compared to their non-alexithymic counterparts (mean: 159.33 ± 76.96).