Verbal declarative memory and language lateralization in patients with major depression: A functional transcranial Doppler sonography (fTCD) study

Objectives: Recurrent Major Depression (MD) is accompanied by alterations in temporal lobe structures and deficits in verbal declarative memory. This study investigated the frequency of atypical language dominance and verbal declarative memory function in patients with MD. Methods: 21 right-handed patients (Age: 54,4 ± 14,7) with recurrent MD were investigated with fTCD and a lexical word generation paradigm. Cerebral blood velocities (CBFV)in both middle cerebral arteries were analyzed with the software Average®. Relative increase in CBFV during word generation compared to resting was computed. From the interhemispheric differences, a lateralization index (LI) was calculated. Severity of depressive symptomatology was assessed with The Montgomery Asberg Depression Rating Scale (MADRS). Results: Depressive patients showed more frequently an atypical language dominance than healthy controls (29% vs. 9%; p < .05). Depressive patients and controls with atypical language dominance showed no differece in LI(3,9 vs. 4,3 p > .1). The maximal relative increase in CBFV, in both middle cerebral arteries, was significantly decreased in MD compared to controls (ACM links 8,7% vs. 14,0%, ACM rechts 7,0% vs. 11,2%; p < .01). Conclusions: We found preliminary evidence that the incidence of atypical language lateralization is increased in patients with recurrent depression, although the pathophysiological basis underlying this association remains unclear and should be addressed in further studies.