The Relation of Phoneme Discrimination, Lexical Access, and Short-Term Memory: A Case Study and Interactive Activation Account

• Published in: Brain and language Vol. 70; no. 3; pp. 437 - 482
• Main Authors: Martin, Randi C., Breedin, Sarah D., Damian, Markus F.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.12.1999; Elsevier
• Subjects: Adult and adolescent clinical studies; Aphasia - diagnosis; Aphasia - etiology; Biological and medical sciences; Brain Injuries - complications; Decision Making; Humans; Language and communication disorders; Male; Medical sciences; Memory, Short-Term - physiology; Middle Aged; Neurology; Phonetics; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Reaction Time; Speech Perception - physiology; Vascular diseases and vascular malformations of the nervous system; Vocabulary; Short term; Human; Nervous system diseases; Stroke; Cognitive disorder; Memory; Cardiovascular disease; Verbal perception; Phonem; Language disorder; Cerebral disorder; Vascular disease; Case study; Hearing; Discrimination; Vision; Central nervous system disease; Lexical decision; Speech; Cerebrovascular disease
• ISSN: 0093-934X; 1090-2155
• DOI: 10.1006/brln.1999.2184

A brain-damaged patient (AP) is reported who had a strong tendency to identify nonwords as words on auditory lexical decision and to lexicalize nonwords in repetition, yet who showed a normal ability to perceive individual phonemes. It was initially hypothesized that these findings could be accounted for in terms of disrupted lexical phonological representations. This hypothesis was rejected on the basis of an interactive activation model of word recognition which revealed that modifications at the lexical level did not mimic the patient's pattern of results. Instead, it was found that increasing the rate of decay of activation at the phoneme level produced output that was consistent with the phoneme discrimination, lexical decision, and repetition results. This hypothesis of increased phoneme level decay led to the prediction that speech discrimination would decline with increased interstimulus interval and that short-term memory performance would be impaired. Both predictions were confirmed. The results of this study provide support for an interactive activation model of word recognition with feedback from the lexical to the phonemic level and for a close connection between the processes involved in word recognition and short-term memory.