Distinctive MMN relative to sound types in adults with intellectual disability.
The effect of stimulus characteristics (vowel vs pure tone) upon mismatch negativity (MMN) was compared between adults with intellectual disability and healthy controls. Either vowels (synthesized vowels /e/ and /o/) or pure tones (1940 and 851 Hz corresponding to the F2 frequencies of /e/ and /o/, respectively) were presented using an oddball procedure. Both groups showed identical results in latency (vowel MMN>pure tone MMN) and less amplitudes for vowels. However, the disabled group demonstrated amplitude attenuation regardless of the stimulus type, although the vowel MMN amplitude showed a descending trend with age in both groups. These results suggest that auditory sensory memory in intellectual disability might have an insufficient capacity yet share a property common to controls.
Ikeda
Kazunari
K
Research Institute for Education of Exceptional Children, Tokyo Gakugei University, Koganei, Tokyo 184-8501, Japan. kazunari@u-gakugei.ac.jp
Hayashi
Akiko
A
Hashimoto
Souichi
S
Kanno
Atsushi
A
D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D000704:Analysis of Variance; D001307:Auditory Perception / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000503:physiopathology*; D007361:Intelligence Tests / Q000706:statistics & numerical data; D008297:Male; D011930:Reaction Time / Q000502:physiology*