Gerald J. Canter

Impairment of Voice and Face Recognition in Patients with Hemispheric Damage

Voice and face recognition were tested in 21 left- and 9 right-hemisphere-damaged patients. Test materials were photographs and recordings of famous political and entertainment personalities. Pathological face recognition (prosopagnosia) and voice recognition (phonagnosia) were both significantly more prevalent in the right-hemisphere group. Only one instance of prosopagnosia and one of phonagnosia were observed in the left-hemisphere group, all of whom were aphasic. Of the right-hemisphere cases, there were four instances of each agnosia, with three patients showing a dual impairment. These findings are discussed in relation to differential modes of processing by the two cerebral hemispheres.

Apraxia of speech in patients with Broca's aphasia: A study of phoneme production accuracy and error patterns

Abstract Phonetic analyses were made of the articulatory errors of ten Brocas aphasics with apraxia of speech. Presentation mode, phoneme position, and phoneme frequency-of-occurrence were related to phoneme difficulty. Consonant clusters were more difficult than consonant singletons; vowels were easiest. Substitution, addition, and compound errors predominated, while distortions and omissions were much less frequent. A subphonemic feature analysis of substitution and distortion errors showed a majority of errors to be close approximations to target phonemes.

Action-Naming Performance in Four Syndromes of Aphasia

This study examined the influence of two situational contexts on the action-naming performances of 44 aphasic patients: single-word confrontation naming and naming within the context of connected speech. Subjects were evenly distributed among the syndromes of Brocas. Wernickes, anomic, and conduction aphasia. The two naming tasks employed each comprised the same 18 target verbs. Naming performance was not systematically influenced by the particular naming task in any of the aphasia groups studied. However, for some individuals, particularly in the group of anomic aphasia, there were substantial performance discrepancies between scores obtained on the two different tasks. Correlations between scores on the confrontation-naming and picture-description tasks were highest for the Wernickes aphasics, followed by the conduction, Brocas, and anomic aphasics. The extent to which action-naming error types could discriminate between the four groups of aphasics was examined. Results obtained in the present study were compared to results obtained in an earlier study on object-naming (S. Williams & G. Canter, 1982), Brain and Language, 17, 92-106). Discussion focuses on implications for the psycholinguistic processes involved in action versus object-naming.

Contrasting speech patterns in apraxia of speech and phonemic paraphasia

This study was designed to determine if perceptual phonological analysis would reveal distinctions between patients with apraxia of speech and patients with phonemic paraphasic speech. Test findings from 10 Brocas aphasics with apraxia of speech were compared to findings from 10 paraphasic speakers (5 conduction and 5 Wernickes aphasics). Several marked differences were revealed. Predominant locus of errors and relative difficulty of different classes of phonemic segments were significant discriminators. There was a nonsignificant trend for substituted phonemes to be further from target phonetically in the paraphasic patients. In addition, the two groups showed certain consistent differences in the types of errors they produced. Apraxic patients produced many errors of transitionalization, while sequencing errors were more typical of the patients with phonemic paraphasia. The findings are interpreted in relation to a neuropsychological model of speech. It is suggested that phonemic paraphasia represents a breakdown mainly in the retrieval of phonological word patterns, while apraxia of speech is characterized predominantly by a disturbance in encoding phonological patterns into appropriate speech movements.

The influence of situational context on naming performance in aphasic syndromes

Abstract This study examined the influence of two situational contexts on the naming performances of 40 aphasic patients: single-word confrontation naming and picture description. The subjects were evenly distributed among the syndromes of Brocas, Wernickes, conduction, and amnesic aphasia. The two naming tasks used were each comprised of the same 40 target words. Patients with Brocas aphasia performed significantly better on confrontation naming than when naming on the picture-description task. In contrast, patients with Wernickes aphasia displayed significantly better performance on the picture-description task. Although individual patients in the groups of amnesic and conduction aphasia were also influenced by the nature of the naming task being performed, neither of these groups showed a consistent pattern of performance differences on the two tasks. Patterns of naming errors produced within each group of aphasics were also examined. Differential error patterns were determined for these four diagnostic groups. The results are discussed in relation to neuropsychological concepts of aphasia and the naming process. Diagnostic and therapeutic implications are also addressed.

Observations On Neurogenic Stuttering: A Contribution to Differential Diagnosis

The search for the etiology of stuttering goes back to ancient times. For centuries, it was considered probable that some kind of defect in the peripheral speech mechanism was causal. During the present century, there has been great interest in the possible significance of certain central physiological dysfunctions including biochemical, neuromotor, and neurosensory. Some theorists and clinicians, especially those with psychoanalytic orientations, have viewed stuttering as an overt manifestation of an underlying neurosis. During the past quarter century, increasing attention has been given to stuttering as learned behaviour - a distortion of normal developmental speech dysfluency due to adverse evaluation.

Phonemic behavior of aphasic patients with posterior cerebral lesions

Abstract The investigation analyzed the phonemic paraphasic errors of 10 asphasic patients with posterior cerebral lesions. The results indicated that paraphasic speech is characterized by complex confusions, often occurring at the ends of words and often involving phonemic transpositions. Many of the unusual and unexpected phonemic errors appeared to be due to simultaneous semantic and phonologic confusions.

Neurogenic acquired stuttering

We were formally introduced to the phenomenon of acquired stuttering in 1976 when a 33-yr-old patient was admitted to the AphasiaNeurobehavior Unit of the Boston Veterans Administration Hospital with a seizure disorder which developed following a head injury. Along with the seizure the patient had developed a profound stutter, characterized by phonemic repetitions of virtually every syllable. He had no history of developmental speech or language problems. The clinicians responsible for this patient’s treatment were confronted with the problem of determining whether the etiology was psychogenic or neurogenic. This prompted us to investigate the problem of acquired stuttering. With little effort seven additional patients with adult onset of stuttering were recalled. In characterizing their speech problem we were drawn to the definition presented by Espir and Rose (1970) who characterized stuttering as “a deviation of speech which affects adversely the speaker or listener because of an interruption of the normal rhythm of speech by an involuntary repetition, prolongation or arrest of sounds.” Definitions which implied a developmental etiology were rejected because our patients clearly began to stutter subsequent to neurolgical injury during adulthood. At the same time we began a retrospective examination of these seven patients, a literature search was undertaken. It was striking to find that while a single bibliography in developmental stuttering may run over 600 references (Bloodstein, 1969) we were able to locate less than a dozen references to acquired stuttering, since this phenomenon was first

Comprehension of sentence structure in anomic and conduction aphasia

Picture-pointing auditory and reading comprehension tests were administered to anomic and conduction aphasics. Subjects responded to active sentences of the present progressive form. The possible errors which a subject could make on these experimental tasks included failure to correctly interpret noun order, number, or lexical meaning. Both groups made significantly more correct responses than error responses. Of their error responses, noun-order errors significantly exceeded number and lexical errors for which no differences were observed. When compared with results previously obtained for agrammatic Brocas aphasics, no differences in the pattern of errors were identified. These results are discussed relative to current theories of syntactic processing and for the mechanisms which account for these syntactic comprehension deficits following aphasia.

Neuropsychological analysis of a typewriting disturbance following cerebral damage

Following a left CVA, a skilled professional typist sustained a disturbance of typing disproportionate to her handwriting disturbance. Typing errors were predominantly of the sequencing type, with spatial errors much less frequent, suggesting that the impairment was based on a relatively early (premotor) stage of processing. Depriving the subject of visual feedback during handwriting greatly increased her error rate. Similarly, interfering with auditory feedback during speech substantially reduced her self-correction of speech errors. These findings suggested that impaired ability to utilize somesthetic information--probably caused by the subjects parietal lobe lesion--may have been the basis of the typing disorder.