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Biomedical subjects

L Nickels

Publications and source records attributed to L Nickels.

6 recordsLinked to original sources
PubMed1997

Fractionating the articulatory loop: dissociations and associations in phonological recoding in aphasia.

This paper uses neuropsychological data to differentiate between three models of verbal short-term memory (Baddeley, 1983, 1986; Besner, 1987; Monsell, 1987). The focus is on three tasks: homophone judgments, rhyme judgments and pseudohomophone detection. When lesioned each model predicts characteristic patterns of impairment across these tasks. Thirteen span impaired aphasic subjects were assessed on all three tasks. The patterns of performance unequivocally supported the model proposed by Monsell (1987) which distinguishes input and output phonological buffers. Implications for further research are discussed.

Adult↗
PubMed1995

Aphasic naming: what matters?

This paper investigates the factors which affect naming performance for two groups of aphasic subjects. The effects of word age-of-acquisition, operativity, frequency, familiarity, imageability, concreteness, length and the visual complexity of the stimulus picture were examined. In contrast to previous studies, we found remarkably small effects of word frequency on naming performance; these studies, we argue, have failed to control sufficiently for the effects of variables which intercorrelate with frequency. However, many patients were significantly affected by age-of-acquisition even when any effects of frequency and familiarity had been accounted for. Operativity, imageability and word length were also predictive of naming performance for some of the patients investigated, unlike visual complexity. The applicability of conclusions drawn from groups of aphasics is again thrown into doubt, as these two groups showed different patterns of predictor variables, and the variables affecting the performance of individuals could be different from those affecting the group.

Adult↗
PubMed1995

Phonological errors in aphasic naming: comprehension, monitoring and lexicality.

This paper investigates the production of phonological errors in aphasic naming, examining the relationship between these errors and deficits in comprehension. The predictions of Dell and O'Seaghda's (1991) computational model of speech production were tested by lesioning. The set of lesioned models demonstrated a strong correlation between proportion of phonologically related errors in naming and comprehension accuracy. In contrast, no correlation between proportion of phonological errors in naming and comprehension accuracy was found for a group of fifteen aphasics. This paper also examines monitoring behaviours, such as the presence of self-corrections and interrupted responses, again finding no relationship with auditory comprehension. There was also no evidence for a lexical bias in the phonological errors for these aphasic subjects. Phonologically related errors were argued to be words only by chance; this was supported by the fact that they occurred more frequently on short words than long words, and that the proportion of real word errors was not significantly different to that observed in a pseudocorpus of errors. We conclude that a production-based monitor would be compatible with these results but that any comprehension-based monitor is not reliably employed by some or all of the aphasic subjects examined here. Additionally, these data are incompatible with models of language processing where speech input and output share the same processing components.

Adult↗
PubMed1995

Reading too little into reading?: strategies in the rehabilitation of acquired dyslexia.

This paper examines four recent therapy studies, two involving deep dyslexic patients and two involving surface dyslexic patients. These studies illustrate that remediation of aspects of acquired dyslexia can have positive benefits for the patients concerned which often extend beyond an improvement in reading aloud. It is argued that, although it may not be immediately apparent, the remediation of acquired reading impairments (and even of reading aloud) can be of functional significance for an aphasic subject.

Dyslexia, Acquired↗
PubMed1991

Sentence processing deficits: a replication of therapy.

This paper describes the replication of a therapeutic programme originally used by one of the authors, Byng (Cognitive Neuropsychology, 1988, 5, 629-676) to remediate a specific sentence processing deficit. Our patient is shown to have similar although not identical deficits to those of one of the patients (JG) described in that programme. Sentence comprehension and production both improved as a result of therapy. The pattern of results observed gave further insights into both the nature of the patient's deficit and the mechanism of therapy.

Aged↗