RECOGNITION OF DICHOTIC DOUBLE DIGITS IN YOUNG AND ELDERLY CANTONESE-SPEAKING LISTENERS

Kam ACS (1), Keith RW (2).

(1)  Department of Otorhinolaryngology, Head & Neck Surgery, Chinese University of Hong Kong, Hong Kong and  Institute of Human Communicative Research, Chinese University of Hong Kong, Hong Kong; (2)  Department of Otolaryngology, University of Cincinnati, US.

Background:Dichotic listening tests are commonly used in assessing children and adults suspected of auditory processing problems, especially in search of interaural asymmetry. In general, the effects of aging on dichotic speech recognition result in poorer performance and larger REAs for older adults relative to findings for young adults. As Chinese and English differ completely in phonology, morphology and syntax, it seems reasonable to suspect if their cerebral representations would be different.

Aim:The primary purpose of the present research study was to determine if differences in dichotic listening performance exist between young adults with normal hearing and older adults with minimal sensorineural hearing loss in the Cantonese-speaking population.

Methods:Cantonese dichotic digits recognition was evaluated in free-recall, directed-attention right, and directed-attention left response conditions. All participants were right-handed and included a group of young adults (n = 30, age range = 20-35) with normal hearing and a group of older adults (n = 30, age range = 65-80) with minimal sensorineural hearing loss. 

Results:In all conditions, performance by the young adults was better than performance by the older adults. A right-ear advantage (REA) was observed for both groups. Due to a greater deficit in dichotic digits recognition performance for digits presented to the left ear of older subjects their REAs were larger than those for the young adults.

Conclusions:The results support an age-related disadvantage in recognition performance for dichotic stimuli presented to the left ear not entirely accounted for by differences in hearing sensitivity between subject groups but may be related to a primary cognitive deficit.

E-mail:annakam@ent.cuhk.edu.hk