Transcallosal inhibition in patients with and without alexithymia.
OBJECTIVE
Previous results indicated a facilitated transcallosal inhibition via the corpus callosum (CC) in alexithymic male students. This study investigates transcallosal inhibition in alexithymic and nonalexithymic psychiatric inpatients.


METHODS
Transcallosal inhibition was elicited by means of transcranial magnetic stimulation (TMS) of the primary motor cortex. Seven right-handed male and 12 female psychiatric patients with Toronto Alexithymia Scale (TAS-20) scores of > or = 61 and 12 patients with TAS-20 scores of < 51 were investigated. The transcallosal conduction time (TCT) reflects the TMS-induced inhibitory cortical activity that is mediated via the CC.


RESULTS
There was a significant effect of alexithymia on TCT (Wilks lambda = 0.76; F = 4.1; d.f. = 2, 26; p = 0.027) indicating that alexithymic patients had shorter bidirectional TCTs than nonalexithymic patients. The in-between models showed a significant impact of alexithymia on both right to left TCT (F = 4.8; d.f. = 1; p = 0.038) and left to right TCT (F = 5.0; d.f. = 1; p = 0.033). Neither gender nor scores of depression (Montgomery-Asberg Depression Rating Scale) had any significant effects on TCT.


CONCLUSIONS
Our results confirm and extend the previous findings of a facilitated, bidirectional transcallosal inhibition in alexithymia to male and female psychiatric inpatients. Facilitated transcallosal inhibition should be considered as a neurobiological correlate of alexithymia.
Department of Psychiatry and Psychotherapy, Ernst-Moritz-Arndt University, Greifswald/Stralsund, Germany. Jan@Richter-MV.de
Jan
J
Richter
Bertram
B
Möller
Carsten
C
Spitzer
Susanne
S
Letzel
Susanne
S
Bartols
Sven
S
Barnow
Carsten
C
Willert
Harald Jürgen
HJ
Freyberger
Hans Jörgen
HJ
Grabe
D000328:Adult; D000342:Affective Symptoms / Q000209:etiology / Q000503:physiopathology*; D003337:Corpus Callosum / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000150:complications / Q000503:physiopathology*; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology; D015999:Multivariate Analysis; D009431:Neural Conduction; D009433:Neural Inhibition; D011569:Psychiatric Status Rating Scales; D050781:Transcranial Magnetic Stimulation