Evidence of normal hearing laterality in familial schizophrenic patients and their relatives

Abstract

Dichotic listening (DL) has been used as a tool to investigate possible left cerebral dysfunction in schizophrenia. However, the wide range of DL tests (e.g., words, emotions, sentences) as well as patient groups ("heterogeneity") has introduced several confounders. Assessing relatives of patients with schizophrenia may overcome some of these problems, and may be more useful in determining if loss of functional cerebral laterality in schizophrenia is a state or a trait phenomenon. The fused consonant-vowel DL test was administered to 114 subjects: 20 individuals with familial schizophrenia, 42 of their healthy relatives, and 52 healthy volunteers. We did this to investigate whether the normal language processing asymmetry-a right ear advantage (REA)-is present, and whether it could serve as a marker for genetic liability. General performance accuracy level was lower in schizophrenia patients and their relatives but the expected REA was present in all groups. Adjusting for age, accuracy, and obligate status made no difference. In conclusion, familial schizophrenic patients and their relatives have normal REA and hearing laterality on the fused DL test.

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

“…Toulopoulou, Chua, Lam, Cheung, Murray and David () assessed healthy family members of schizophrenia patients, along with the patients themselves and healthy controls. Although general DL performance of patients and their family members was significantly lower than of healthy controls, the laterality index (REA) didn't differ significantly between the three groups.…”

Implications for Early Diagnosis and Treatment in Schizophrenia Due to Correlation between Auditory Perceptual Deficits and Cognitive Impairment

“…In most cases, the only test used for auditory processing evaluation was DL, leading to incomplete evaluation of elements of auditory processing that are essential for everyday communication. Most DL studies showed that the binaural performance of patients was significantly poorer compared to that of healthy subjects [ 6 , 7 , 8 , 9 , 10 , 11 ]. Furthermore, patients with schizophrenia had reduced laterality [ 12 ].…”