Stimulus-dependent effects on right ear advantage in schizophrenia

Abstract

BackgroundWhen presented with different sounds in each ear (dichotic listening), healthy subjects typically show a preference for stimuli heard in the right ear, an effect termed “right ear advantage”. Previous studies examining right ear advantage in schizophrenia have been inconsistent, showing either decreased or increased advantage relative to comparison subjects. Given evidence for enhanced semantic processing in schizophrenia, some of this inconsistency may be due to the type of stimuli presented (words or syllables). The present study examined right ear advantage in patients and controls using both words and syllables as stimuli.MethodsRight ear advantage was compared between 20 patients with schizophrenia and 17 healthy controls. Two versions of the task were used, ie, a consonant-vowel pairing task and a fused rhymed words task.ResultsA significant group × task interaction was observed. Relative to healthy controls, patients showed a greater difference on the syllable-based task compared with the word-based task. The number of distractors marked during the syllable-based task was inversely correlated with score on the Global Assessment of Function Scale.ConclusionThe findings are consistent with a left hemisphere dysfunction in schizophrenia, but also suggest that differences may be stimulus-specific, with a relative sparing of the deficit in the context of word stimuli. Performance may be related to measures of social, occupational, and psychological function.

Behavioral assessment of auditory processing deficits in schizophrenia: Literature review and suggestions for future research

“…The results of the 15 dichotic listening studies were heterogeneous. Whereas in some cases there were no significant differences between individuals with schizophrenia and healthy controls in their DL performance (Hahn et al ., ; Løberg, Jørgensen & Hugdahl, ; Øie et al ., ; Rominger et al ., ; Smucny et al ., ), in most studies the DL scores of schizophrenia patients were significantly reduced than controls'. In Øie and Hugdahl () follow‐up study, patients' laterality was significantly reduced in the non‐forced condition and reverse in the forced‐left condition, compared to the first study (Øie et al ., ), indicating that functional hemispheric asymmetry, as well as top‐down control, may be reduced with age in schizophrenia.…”

“…Another study that examined REA in patients with schizophrenia was that of Smucny, Wylie and Tregellas (), who administered two versions of a DL test, using either words or syllables as stimuli. In both tests, patients' laterality was smaller than controls', with a large effect size (Hedges' g > 0.8).…”

“…(), implemented a complete APD battery, whereas others used mainly DL tasks and other non‐routine auditory cognition tests. Some authors chose the terms “auditory (processing) deficits” (Collinson et al ., ; Kantrowitz et al ., ; McKay et al ., ; McLachlan et al ., ; Petkova et al ., ; Rossell & Boundy, ) and “auditory (processing) abnormalities” (McKay et al ., ; Smucny et al ., ). This may reflect the limited popularity of the term “Auditory Processing Disorder” among psychiatrists, as well as a preference for more general and flexible terms, such as “auditory deficits” or “abnormalities.” Furthermore, only McKay et al .…”

“…Considering effect size, Hedges' g was calculated in 12 studies (Bozikas et al ., ; Force et al ., ; Friedman et al ., ; Hahn et al ., ; Iliadou et al ., ; Iwashiro et al ., ; Løberg et al ., ; McKay et al ., ; Øie et al ., ; Rossell & Boundy, ; Rossell et al ., ; Smucny et al ., ), where information about means, standard deviations and sample sizes was available. Most of the effect sizes in these studies were small and medium, and in only six studies (Bozikas et al ., ; Force et al ., ; Iliadou et al ., ; McKay et al ., ; Rossell & Boundy, ; Smucny et al ., ) there was found at least one large effect size (0.8 or greater). Future researchers may consider using larger sample sizes.…”

Συσχέτιση Των Διαταραχών Ακουστικής Επεξεργασίας Με Τη Διαταραχή Στη Ροή Της Σκέψης Σε Ασθενείς Με Σχιζοφρένεια

“…Another study that examined REA in patients with schizophrenia was that of Smucny, Wylie and Tregellas (2012), who administered two versions of a DL test, using either words or syllables as stimuli. In both tests, patients' laterality was smaller than controls', with a large effect size (Hedges' g > 0.8).…”