Auditory frequency discrimination in adult developmental dyslexics.
Developmental dyslexics reportedly discriminate auditory frequency poorly. A recent study found no such deficit. Unlike its predecessors, however, it employed multiple exposures per trial to the standard stimulus. To investigate whether this affects frequency discrimination in dyslexics, a traditional two-interval same-different paradigm (2I_1A_X) and a variant with six A-stimuli per trial (2I_6A_X) were used here. Frequency varied around 500 Hz; interstimulus interval (ISI) ranged between 0 and 1,000 msec. Under 2I_1A_X, dyslexics always had larger just noticeable differences (JNDs) than did controls. Dyslexic and control JNDs were equal at shorter ISIs under 2I_6A_X, but dyslexics became worse than controls at longer ISIs. Signal detection analysis suggests that both sensory variance and trace variance are larger in dyslexics than in controls.
France
S J
SJ
University of Oxford, England.
Rosner
B S
BS
Hansen
P C
PC
Calvin
C
C
Talcott
J B
JB
Richardson
A J
AJ
Stein
J F
JF
D000328:Adult; D001288:Attention; D004410:Dyslexia / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D010897:Pitch Discrimination; D011571:Psychoacoustics; D013018:Sound Spectrography