Neural correlates of enhanced working-memory performance in dissociative disorder: a functional MRI study.
BACKGROUND
Memory functioning has been highlighted as a central issue in pathological dissociation. In non-pathological dissociation, evidence for enhanced working memory has been found, together with greater task-load related activity. So far, no imaging studies have investigated working memory in dissociative patients.


METHODS
To assess working memory in dissociative patients functional magnetic resonance imaging was used during performance of a parametric, verbal working-memory task in patients with a dissociative disorder (n=16) and healthy controls (n=16).


RESULTS
Imaging data showed that both groups activated brain regions typically involved in working memory, i.e. anterior, dorsolateral and ventrolateral prefrontal cortex (PFC), and parietal cortex. Dissociative patients showed more activation in these areas, particularly in the left anterior PFC, dorsolateral PFC and parietal cortex. In line with these findings, patients made fewer errors with increasing task load compared to controls, despite the fact that they felt more anxious and less concentrated during task performance.


CONCLUSIONS
These results extend findings in non-pathological high dissociative individuals, suggesting that trait dissociation is associated with enhanced working-memory capacities. This may distinguish dissociative patients from patients with post-traumatic stress disorder, who are generally characterized by impaired working memory.
Elzinga
Bernet M
BM
Section of Clinical and Health Psychology, University of Leiden, Leiden, The Netherlands. Elzinga@fsw.leidenuniv.nl
Ardon
Angelique M
AM
Heijnis
Maaike K
MK
De Ruiter
Michiel B
MB
Van Dyck
Richard
R
Veltman
Dick J
DJ
D000328:Adult; D001921:Brain / Q000473:pathology*; D004213:Dissociative Disorders / Q000523:psychology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008568:Memory; D008875:Middle Aged; D009422:Nervous System Diseases / Q000175:diagnosis* / Q000453:epidemiology; D012016:Reference Values; D013060:Speech