Poor Frequency Discrimination Probes Dyslexics with Particularly Impaired Working Memory

Vol. 9, No. 6, 2004

Free Abstract Article (Fulltext) Article (PDF 225 KB)

Original Paper

Poor Frequency Discrimination Probes Dyslexics with Particularly Impaired Working Memory
Karen Banai^a, Merav Ahissar^b

Departments of
^aNeurobiology and
^bPsychology, Hebrew University of Jerusalem, Jerusalem, Israel

Address of Corresponding Author

Audiology & Neuro-Otology 2004;9:328-340 (DOI: 10.1159/000081282)

Key Words

Dyslexia
Auditory processing
Frequency discrimination
Working memory

Abstract

Substantial difficulties in performing simple auditory discriminations were previously found in some individuals with a specific reading disability but not in others. This high variability in psychoacoustic performance raises the question of whether this difficulty is related to the reading deficit. Addressing this question, we compared adult dyslexics with and without difficulty in simple auditory discriminations, using 2-tone frequency discrimination as our probe. The distribution of their frequency discrimination scores was bimodal. On this basis, we divided our participants into subgroups having either poor or adequate psychoacoustic performance. Only dyslexics with poor psychoacoustic scores had significantly impaired verbal working memory compared to their matched controls. Furthermore, and only in this subgroup, working memory scores were correlated with both cognitive abilities and reading-related tasks. Consistent with the hypothesis that in this subgroup poor working memory impedes performance in a broad range of academically related tasks, we found that the majority of dyslexics in this subgroup had more extensive academic difficulties and consequently needed special support in schools. We propose that dyslexics with poor psychoacoustic abilities form a distinct subtype of dyslexia in which the core deficit is not specific to phonological components. For these individuals, poor verbal working memory may be the main impediment to success in academic environments.

Author Contacts

Dr. Merav Ahissar
Department of Psychology
Hebrew University of Jerusalem, Mt. Scopus
Jerusalem 91905 (Israel)
Tel. +972 2 5883409, Fax +972 2 5881159, E-Mail msmerava@mscc.huji.ac.il

Article Information

Received: October 21, 2003
Accepted after revision: March 18, 2004
Published online: October 1, 2004
Number of Print Pages : 13
Number of Figures : 4, Number of Tables : 1, Number of References : 65

Medline Abstract (ID 15467286)

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