Single and double dichotic digit tests in Malay language were developed and standardized as an initial attempt to incorporate tests of auditory processing within the scope of audiology practice in Malaysia. Normative data under free recall, directed right-ear first, and directed left-ear first listening conditions were determined using 120 Malay children between the ages of 6 and 11 years old with normal hearing and normal academic performance. Test-retest reliability was assessed in 15 of the study subjects. In general, the double dichotic digit test produced greater differences in scores between age groups, and a greater right-ear advantage than the single dichotic digit test. In addition, the double dichotic digit test also had higher test-retest reliability. These findings suggest the double dichotic digit test is more clinically applicable.
This study assessed the effects of age and working memory capacity on dichotic listening and temporal sequencing. Double Dichotic Digit Test (DDT), Pitch Pattern Sequence Test (PPST) and Digit Span Test were administered on 40 healthy adults with hearing thresholds of not greater than 30 dB HL across octave frequencies from 250 to 4000 Hz. Twenty young (20-30 years old) and 20 older (50-65 years old) adults were included in the study. Results showed that the older group had significantly lower scores in DDT, PPST and working memory capacity measures than the young subjects. Working memory capacity was positively correlated with PPST but not with DDT, suggesting that DDT might be more auditory-modality-specific than PPST.