Sprachdominanz und Verbalgedächtnis bei Patienten mit rezidivierender depressiver Erkrankung : eine Studie mittels funktioneller transkranieller Dopplersonographie (fTCD)

In the present study we wanted to investigate the dimension of left-hemispheric language dominance of patients with Major Depression (MD) using an established word generation paradigm. A possible atypical dominance for language could give evidence of left-temporal functional disturbances and may help to characterize their influence on depressive disorders. In addition, we executed a German vocabulary test (Wortschatztest, WST; Schmidt and Metzler, 1992) and a German form of the Rey Auditory Verbal Learning Test (Verbaler Lern- und Merkfähigkeitstest, VLMT; Helmstaedter et al., 2001) to examine further functions of the temporal lobe. Methods: Twenty-one right-handed patients with major depressive disorder and 35 healthy volunteers participated in the study. Cerebral blood flow velocity (CBFV) in the M1 segment of both middle cerebral arteries (MCA) was measured simultaneously and continuously during performance of a language paradigm. A laterality index (LI) was calculated separately for each individual. Results: Patients showed higher frequency (28.6% vs. 8.6%) of atypical language dominance during word generation, so that there were significantly more patients with right hemispheric or bilateral representation of language in relation to controls (ᵡ2= 3.892, p= .049). No connection between illness duration, severity of illness or medication and fTCD-lateralization was observed. Regarding VLMT performance, patients compared to controls showed significantly worse performance regarding immediate learning and recall after delay. Estimated Verbal-IQ differed significantly. Discussion: The more frequent atypical language dominance in depressive patients could indicate a link between left-temporal functional disorder and major depression. No influence of the severity of the illness or illness duration on laterality index could be found, so that our results rather support the assumption of a predisposition for psychiatric diseases caused by decreased hemispheric asymmetry than a language shift. An alteration of LI due to illness-associated factors like anxiety, restlessness or deficits in attention could not be observed and has to be proved in detail in following studies.