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Biomedical subjects

J Gandour

Publications and source records attributed to J Gandour.

At least 37 records · Page 2Linked to original sources
PubMed1993

Intraword timing relations in Thai after unilateral brain damage.

The present study examined temporal characteristics of monosyllabic, bisyallabic, and trisyllabic words in Thai to evaluate timing control at the word level in brain-damaged patients. Subjects included young and old normal adults, right hemisphere patients, and left hemisphere nonfluent and fluent aphasic patients. Utterances were produced at a conversational speaking rate. Results indicated that, on an absolute or relative measurement scale, magnitude of the shortening effect on nonfinal syllables in polysyllabic words was significantly smaller in left nonfluent aphasics than in other groups. In trisyllabic words, duration of the penultimate syllable for left fluent aphasics was also significantly longer than that of normals. Left nonfluent and fluent aphasics were significantly more variable than other speakers in their production of bisyllabic and trisyllabic words. Findings are discussed in relation to issues pertaining to the nature of timing deficits in nonfluent and fluent aphasic patients.

Adult↗
PubMed1992

Timing characteristics of speech after brain damage: vowel length in Thai.

This paper explores the extent of timing deficits in vowels produced by brain-damaged speakers of a language with a phonological contrast in vowel length. Short and long vowels in Thai were produced in isolated monosyllabic words by 20 normal adults, 14 right hemisphere patients, and 17 left hemisphere aphasics. Vowel durations were measured spectrographically. Although the phonological contrast was relatively preserved, as indicated by average duration, a subtle timing deficit in vowels produced by nonfluent aphasics was indicated by a compressed duration continuum and increased variability in vowel production.

Adult↗
PubMed1992

Lexical tones in Thai after unilateral brain damage.

An acoustic perceptual investigation of the five lexical tones of Thai was conducted to evaluate the nature of tonal disruption in patients with unilateral lesions in the left and right hemisphere. Subjects (n = 48) included 10 young normal adults, 10 old normal adults, 11 right hemisphere nonaphasics, 9 left hemisphere fluent aphasics, and 8 left hemisphere nonfluent aphasics. The five Thai tones (mid, low, falling, high, rising) were produced in isolated monosyllables, presented for tonal identification judgments, and measured for fundamental frequency (Fo) and duration. Results of an analysis of variance indicated that left hemisphere nonfluent speakers signaled and tonal contrasts at a lower level of proficiency. The extent of their impairment varied depending on severity level of aphasia. When compared to normal speakers, tonal identification for less severe nonfluent aphasics differed more in degree than in kind, and for more severe nonfluent aphasics differed both in kind and in degree. Acoustic analysis revealed that with the exception of one left nonfluent, average Fo contours were comparable in shape across speaker groups. Variability in Fo production, however, was greater in left nonfluent speakers than in any of the other four groups of speakers. Issues are discussed regarding the extent and nature of tonal disruption in aphasia and hemispheric specialization for tone production.

Adult↗
PubMed1992

Vowel duration in mothers' speech to young children.

The purpose of this investigation was to determine whether content words are selectively highlighted through increased vowel duration in mothers' speech to young children. Fifteen mother-child dyads served as subjects. All children (ages 1:6-2:4) were female and had a mean length of utterance between 1.00 and 1.40 morphemes. Each mother was asked to read five experimental stories aloud to her child and to an adult. The vowel durations of both content words and function words in these stories were examined. Vowels in content words--but not function words--were significantly longer in child-directed than in adult-directed speech. It is suggested that this characteristic of child-directed speech might heighten young children's attention to content words and contribute to the exclusion of function words during the early stages of English language development.

Female↗
PubMed1991

Nature of spelling errors in a Thai conduction aphasic.

A Thai conduction aphasic's performance on a written confrontation naming task is reported. Analysis of his spelling errors indicated that errors rarely violated Thai phonotactic constraints; consonant substitutions were phonologically similar to the target stimuli; longer stimuli were more likely to be in error; distribution of errors was the same across consonants, vowels, and tones; and distribution of error types varied between segmentals (consonants, vowels) and suprasegmentals (tones). Error patterns were similar to those observed in oral reading and repetition. The pattern of impaired writing performance is discussed in relation to a functional model of the spelling process, and it is hypothesized to reflect primarily a functional lesion to the phonological buffer.

Agraphia↗
PubMed1989

Dysprosody in Broca's aphasia: a case study.

A detailed acoustic analysis of timing, intensity, and fundamental frequency (F0) at different levels of linguistic structure was conducted on the speech output of a Broca's aphasic who was a native speaker of Thai. Timing was measured with respect to syllables, phrases, and sentences in connected speech. Intensity variation at the sentence level was measured in connected speech. F0 variation associated with the five Thai tones was measured in both isolated words and connected speech. Results indicated that timing was differentially impaired depending upon complexity of articulatory gesture and size of the linguistic structure. Timing, as well as intensity, was aberrant at the sentence level. In contrast, F0 contours of the five tones were spared at all levels of linguistic structure. Findings are interpreted to support the view that dysprosody in Broca's aphasia is more applicable to speech timing than to F0.

Aphasia↗
PubMed1989

Idiosyncratic strategies in sentence production: a case report.

In their case study of a patient with selective apraxia of phonation, Marshall, Gandour, and Windsor (1988, Brain and Language, 35, 313-339) reported that many of his utterances were ill-formed syntactically. In this note, a detailed syntactic analysis of his speech is presented. Although the patient's syntax is deviant, it is seen to result from the application of certain consistent, identifiable, compensatory strategies. Moreover, it is shown that the particular, abnormal syntactic structures are internally consistent with his phonatory apraxia coupled with the normal rules of English prosody.

Aphasia↗
PubMed1988

Perception and production of tone in aphasia.

An acoustical and perceptual study of lexical tone was conducted to evaluate the extent and nature of tonal disruption in aphasia. The language under investigation was Thai, a tone language which has five lexical tones--mid, low, falling, high, and rising. Subjects included six left brain-damaged aphasics (two Broca's, one transcortical motor, one global, one conduction, one Wernicke), one right brain-damaged nonaphasic, one cerebellar dysarthric, and five normals. High-quality tape recordings of each subject's productions of a minimal set of five, monosyllabic Thai words were presented to 10 adult Thai listeners for identification. Results from the phonemic identification tests indicated that tone production is relatively spared in aphasic patients with unilateral left hemisphere lesions. The performance of the global aphasic, however, was considerably below normal. Patterns of tonal confusions further revealed that the performance of all aphasics, except the global, differed from that of normal speakers primarily in degree rather than in kind. Tonal contrasts were signaled at a high level of proficiency by the right brain-damaged and dysarthric patients. Acoustical analysis revealed that F0 contours associated with the five tones for all aphasics, except the global, were similar in overall shape as well as position in the tone space to those of normals. F0 contours for the right brain-damaged patient and the dysarthric also generally agreed with those of normals in terms of shape and position. F0 ranges of both aphasic and nonaphasic brain-damaged speakers were generally larger than those of normals for all five tones. The relationship between tone and vowel duration was generally similar to that of normals for all brain-damaged speakers. A comparison of aphasics' performance on tone perception (J. Gandour & R. Dardarananda, 1983, Brain and Language, 18, 94-114) and tone production indicated that, for the normal and right brain-damaged subjects, performance on the perception task was higher than on production, whereas the opposite was true for the aphasics. These data are brought to bear on issues related to tone production in aphasia, consonant and vowel production in aphasia, hemispheric specialization for tone production, intonation production in aphasia, relationship between speech perception and speech production, and tone production in dysarthria with cerebellar disease.

Adult↗
PubMed1988

Selective impairment of phonation: a case study.

A 47-year-old right-handed man underwent craniotomy for clipping of an aneurism at the trifurcation of the left middle cerebral artery. Subsequently, he suffered a left hemisphere CVA after which his speech and language resembled that of Broca's aphasia with accompanying apraxia of speech. Medical, behavioral, and acoustical data amassed over a period of several months indicated numerous contraindications to traditional diagnoses of Broca's aphasia, apraxia of speech, and dysarthria. Ultimately, it was determined that the patient had a selective impairement of phonation or laryngeal apraxia. This was illustrated dramatically when he was taught to use an electrolarynx which allowed him to bypass his disrupted phonatory system. Speaking with the electrolarynx, the patient communicated normally. Any semblance of Broca's aphasia disappeared. Supralaryngeal articulation was normal; apraxia of speech behaviors were absent. This case report indicates that dissociation of oral and laryngeal gestures due to brain injury is possible. Mechanisms underlying such a dissociation for this case are reviewed. The possibility of discrete center lesions in the frontal motor association area causing different types of apraxia of speech is discussed.

Aphasia, Broca↗
PubMed1988

Tone in Thai alaryngeal speech.

The perception and production of linguistic tone was investigated in utterances spoken by Thai alaryngeal speakers. Thai is a tone language with five phonemic tones. High-quality tape recordings of five monosyllabic words produced by 2 esophageal, 1 electrolaryngeal, and 5 normal, native Thai speakers were subjected to perceptual and acoustic analysis. Results from the phonemic identification tests indicated that tones produced by alaryngeal speakers were not only perceived at much lower levels of accuracy than those produced by normal speakers, but the patterns of tonal confusions for alaryngeal speakers were also dissimilar to those for normal speakers. Results from fundamental frequency (Fo) analysis revealed that the performance deficit of alaryngeal speakers could be related to specific characteristics of their Fo contours. Findings are interpreted to highlight the importance of (a) language, (b) type of prosody, (c) form of alaryngeal speech, and (d) Fo level and direction on linguistic assessments of Fo control in alaryngeal speech.

Adult↗
PubMed1987

Voice onset time in Thai alaryngeal speech.

The perception and production of voicing contrast was investigated in utterances spoken by Thai alaryngeal speakers. Thai exhibits a three-category voicing distinction for bilabial /b, p, ph/ and alveolar /d, t, th/ stops and a two-category distinction for velar [k, kh] stops. Voice onset time (VOT) was measured in word-initial stops of words produced in isolation by 2 Thai esophageal speakers and 1 Thai user of an electronic artificial larynx. These measurements were compared with published VOT values for the same words spoken by 5 normal Thai speakers. Both esophageal speakers were capable of signaling voicing distinctions for /b, d/ and /p, t, k/. The electrolaryngeal speaker was able to signal /p, t, k/ only. Thai alaryngeal speakers were generally unsuccessful in signaling /ph, th, kh/. A cross-linguistic comparison to VOT in English suggests that no more than two voicing categories can be distinguished in these two forms of alaryngeal speech. Findings are interpreted to illustrate that the realization of stop voicing contrasts in alaryngeal speech depends on the number of voicing categories in a language, the relative positions of the voicing categories on the VOT continuum, and the form of alaryngeal speech.

Adult↗
PubMed1986

Rhythm in Thai esophageal speech.

Duration measurements associated with rhythmic aspects of speech produced by one Thai esophageal speaker were compared to previously published identical measures for normal Thai speakers. Measures of central tendency and variability were taken of the duration of syllables, pauses, phrases, and interstress intervals. Despite a slower-than-normal overall speaking rate and a shorter-than-normal phrase length, the esophageal speaker was able to maintain normal relative temporal relations among syllables within phrases. Although his speech was dysrhythmic at the overall discourse level, it was rhythmic at the phrase level. Findings are interpreted to highlight the importance of differentiating features of alaryngeal speech that are common across languages from those that are specific to particular languages.

Adult↗
PubMed1985

Rule invention in the acquisition of morphology by a language-impaired child.

This paper presents a case study of a language-impaired child who invented a unique morphophonologic rule for signaling the distinction between English singular and plural nouns. Conventional linguistic-phonetic analysis indicated that the child was producing the distinction suprasegmentally rather than segmentally. Acoustic-phonetic analysis of matched singular-plural noun pairs was performed in order to determine quantitatively which suprasegmental acoustic cues he used to signal the distinction. Results of a multivariate analysis of variance revealed that singular and plural productions were significantly different from one another on various fundamental frequency, duration, and intensity parameters. This example of a child's linguistic creativity is offered as further evidence in support of a model of language acquisition that emphasizes the cognitive aspects underlying linguistic regularities in child language. Clinical implications are also discussed.

Child Language↗
PubMed1984

Voice onset time in aphasia: Thai. II. Production.

The aim of this study was to investigate voice onset time (VOT) production in homorganic word-initial stops in Thai in order to explore the nature of speech production deficits across clinical varieties of aphasia. Thai exhibits a three-category distinction in bilabial (/b,p,ph/) and alveolar (/d,t,t,h/) stops, and a two-category distinction in velar (/k,kh/) stops. Subjects included three Broca asphasics, one transcortical motor asphasic, two global asphasics, one conduction aphasic, one Wernicke aphasic, one nonaphasic dysarthric patient, one right-brain-damaged patient, and five normal controls. Test stimuli consisted of eight monosyllabic real words. The results of VOT measurements indicated that Broca and global asphasics exhibited a more severe production disorder than Wernicke, conduction, or transcortical motor asphasics. The right-brain-damaged patient showed no impairment in VOT production. Comparisons are drawn to earlier studies of VOT production in aphasia in two-category languages. Issues concerning the underlying basis of the production deficit for nonfluent aphasics, fluent aphasics, and nonaphasic dysarthrics as well as the relation between perception and production of VOT are discussed.

Adult↗