Nonverbal communication as a compensative strategy for severely nonfluent aphasics? A quantitative approach

Seven severely nonfluent aphasics and one relative or close friend were investigated in an interview situation. The conversation was videotaped and analyzed for the use of nonverbal communication between aphasic and partner. The results indicate that the group of aphasics used significantly more frequently and for a significantly longer period of time nonverbal channels of communication than their healthy partners. The aphasic patients also used significantly fewer speech-focused movements and significantly more codified gestures. Nonverbal elements were more frequently used as speech substitutes by the group of aphasics.     

Compensation for Jaw Fixation by Aphasic Patients

The ability to compensate for fixation of the jaw by a bite block was investigated in 6 nonfluent aphasics, 6 fluent aphasics, and 10 normal control subjects. Acoustic analyses of the vowels [i u a æ] and fricatives [s s] revealed substantial but incomplete compensation for the perturbation in all three subject groups. Perceptual identification scores and quality ratings by naive and phonetically trained listeners indicated poorer identification of the high vowels [i u] under compensatory conditions relative to normal production. Of particular interest was the fact that all three groups of subjects exhibited similar patterns of results. The findings suggest that any deficit in speech motor programming demonstrated by the nonfluent aphasic patients did not affect compensatory abilities. Results are discussed with respect to normal speech adaptation skills and the nature of articulatory breakdown in nonfluent aphasia.     

The relation between oral movement control and speech

A large series of neurological patients, selected solely on the basis that they had damage restricted to one hemisphere of the brain, was given a variety of tests of basic speech and praxic function. Within the left-damaged group, patients were further identified as aphasic or nonaphasic, based on preexisting standard tests of aphasia. Subgroups of aphasics were studied on the basis of lesion location, rather than on the basis of aphasia type. The focus of the study was the relation between the production of speech and nonspeech oral movements, particularly across anterior and posterior lesions. Reproduction of single nonverbal oral movements and of single isolated speech sounds was found to be very highly correlated, and both depended selectively on the left anterior region of the brain. This same region was critically important for rapid repeated articulation of a syllable, suggesting that it mediates control at some "unit" level of movement, in a phenomenological sense, for both speech and nonspeech movements. Other "speech" regions in the left hemisphere appeared to be dispensable for the production of single oral movements, whether these were verbal or nonverbal movements. However, for most aphasic patients, an area in the left posterior region was inferred to be essential for production of multiple oral movements, whether nonverbal or verbal, suggesting a critical role in the accurate selection of movements. Within the posterior region, there was further differentiation for multisyllabic speech into a parietal system, which appeared to mediate primarily praxic function, and a temporal system, which appeared to mediate verbal-echolalic function. Aphasias from anterior and posterior lesions resembled "Broca's" and "Wernicke's" aphasia only insofar as they differed in fluency, with anterior aphasics clearly less fluent. Tests of speech comprehension did not differentiate the groups. It is suggested that classifying aphasic patients via lesion location rather than aphasic typology might yield a view of functional subsystems different from those commonly accepted.     

An Acoustic Analysis of Rate of Speech Effects on Vowel Production in Aphasia

The present investigation examined the production of tense and lax vowel duration differences at two speaking rates in the speech of 10 nonfluent aphasics, 8 fluent aphasics, and 10 normal control subjects. Subjects produced four repetitions of each of the vowels [i e æ o u I ε υ Λ] at each speaking rate. Acoustic analyses revealed that subjects in all three groups were able to manipulate overall rate of speech. In addition, normal controls and fluent aphasic subjects produced vowels under the fast rate condition which were significantly shorter than those under the slow rate condition. Despite a change in overall speaking rate, the nonfluent aphasics did not exhibit a significant difference in vowel duration at the two rates of speech, suggesting a deficit in the implementation of this temporal parameter. Both normal controls and fluent aphasic patients produced nonoverlapping distributions of tense and lax vowels at both speaking rates. In contrast, the nonfluent aphasics demonstrated a great deal of overlap in the distribution of tense and lax vowel durations at the fast rate. Results are discussed in relation to the nature of the speech production deficits in nonfluent and fluent aphasic patients.     

Comparison of the performances of a fluent and a nonfluent aphasic on a pantomimic referential task

The pantomimic performances of a typical Broca's (nonfluent) and Wernicke's (fluent) aphasic were compared with each other and with four normal control subjects on a simple task of nonverbal referential communication. Both aphasic subjects demonstrated only about 50% accuracy in their pantomimic communication. Also, measures were obtained of the motoric fluency of the pantomimes of all subjects and comparisons were made between the fluent and nonfluent aphasics. These measures demonstrated distinct differences in the fluency patterns of the pantomimes of the two aphasic subjects similar to the differences in speech fluency which distinguish and characterize these two types of aphasia; that is, the fluent aphasic pantomimed fluently and like the control subjects and the nonfluent aphasic pantomimed nonfluently. The quantitative and qualitative similarities in the fluency patterns of the speech and the pantomimic behaviors of the aphasic subjects are discussed in terms of their implications for a definition of aphasia.     

The conceptual structure of aphasic and schizophrenic patients in a nonverbal sorting task

Hierarchical and overlapping cluster methods were applied to the sortings of aphasic, nonaphasic brain-damaged, schizophrenic, and normal subjects presented with 30 pictures of animals. The hierarchical structure solutions were most diffuse for the groups of the schizophrenics and the fluent aphasics. The structure for the nonfluent aphasics showed more clarity, but was also deviant from the structures of the normals and the brain-damaged without aphasia. Fluent aphasics but not nonfluent aphasics tended to sort pictures which they could not name into smaller groups. For the nonfluent aphasics, there was a significant correlation between the commonality of the sortings and the severity of aphasic disturbances as measured by the Token Test. The relationship between conceptual disorganization and language impairment seems to be functionally different for fluent and nonfluent aphasics.This research was supported by a research grant from the Deutsche Forschungsgemeinschaft.     

The quantitative analysis of agrammatic production: procedure and data

Despite the long-standing interest in structural aspects of aphasic production, no method has emerged for the systematic analysis of aphasic speech. This paper attempts to address that need by outlining a procedure for the quantitative assessment of narrative speech which yields measures for both morphological and structural characteristics of aphasic production. In addition to complete instructions for carrying out this analysis, data for three groups of subjects are presented: agrammatic aphasics, aphasics who are similarly nonfluent but not clinically judged as agrammatic, and normal controls. While the agrammatics were distinguishable from the nonagrammatic patients on most measures, both nonfluent groups showed comparable reductions in the structural complexity of their propositional utterances. Other findings include indications from individual patient data that aspects of grammatical morphology may dissociate in agrammatism.     

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.     

Aphasia in Turkish: speech production in Broca's and Wernicke's patients

Turkish speech production was studied in 7 Broca's and 10 Wernicke's aphasics. Turkish is an agglutinative language, with few free-standing closed-class morphemes. The speech of Broca's patients was not telegraphic; although nonfluent, noun and verb suffixes were used appropriately. The speech of Wernicke's aphasics was fluent, using a wide range of often inappropriate forms. Both groups used appropriate nominal morphology. Broca's patients used a limited set of verb forms in contextually appropriate fashion. Wernicke's patients used a wide range of verb forms, all morphosyntactically correct, but often semantically anomalous. Both groups retained canonical subject-object-verb word order and controlled various types of pragmatically appropriate word order variation. It is proposed that aphasic speech patterns reflect retrieval problems rather than impairment of a portion of the language system.     

Target-size influences on reaction time with movement time controlled

The variable that affect motor programming time may be studied by changing the nature of the response and measuring the subsequent changes in reaction time (RT). One notion of motor programming suggests that aiming responses with reduced target size and/or increased target amplitude require more "complex" motor programs that require longer RTs. In a series of five experiments which movement time (MT) was experimentally varied target size neither influences RT when the movement amplitude was 2 or 30 cm nor when the target sizes differed by as much as a factor of 16:1. Increasing the movement amplitude from 15 to 30 cm also had no influence on RT. Movement time, however, did affect RT, with 200-msec movements having longer RTs than 120-msec movements. Target size and movement amplitude did not appear to be factors that influence programming time or program complexity.     

The semantic organization and classification of fourteen words by aphasic patients

The purpose of this study was to assess both conceptual knowledge and classification skills in nonfluent and fluent aphasia by focusing on the aphasics' appreciation of class and function relations. The results illustrated that fluent and nonfluent aphasics appreciated both class and function relations. However, further study revealed that even though the fluent aphasic may know the function of an item, he is impaired in his ability to use this information. The nonfluent aphasics also illustrated this tendency not to use their knowledge about function, but to a lesser extent and without the consistency found in the performance of fluent aphasics.     

Depression in aphasic patients: Frequency, severity, and clinical-pathological correlations

Twenty-five hospitalized nonfluent, fluent, and global aphasic patients who were several months past the onset of their illness were compared for presence and severity of depression based on four psychopathological measures. The nonfluent aphasic patients had both greater frequency and severity of depression than the other two groups. CT scans showed that the global aphasic patients had the largest lesion size (volumetric) and showed a strong correlation between lesion size and degree of depression. In contrast, patients with fluent aphasias showed an inverse correlation between severity of depression and lesion size; among the nonfluent aphasic patients there was no significant correlation. Depression appears to be common in this population of hospitalized aphasic patients with chronic illness and nonfluent patients are the most depressed group within this population. The increased frequency and severity of depression in the nonfluent patients did not appear to be related to their overall physical or cognitive impairment; two possible mechanisms are discussed.     

Impairment of nonverbal oral movements in aphasia

Thirty-six patients with unilateral cerebral vascular damage were required to perform a number of oral motor tasks, both verbal and nonverbal. Nonfluent aphasics were impaired in the imitation of single oral movements, as previously reported. However, on the imitation of complex nonverbal oral movements fluent aphasics were impaired as well as nonfluents. This impairment was not explicable on the basis of visual memory or perceptual deficits, nor on the basis of sensory thresholds as measured on the tongue. The findings suggest that deficits in coordinating oral movements are fundamental to most aphasic impairments, the meaningfulness of the responses not being a critical factor in the appearance of the defect.     

Tonal Coarticulation in Thai after Unilateral Brain Damage

The magnitude and temporal extent of anticipatory and perseverative tonal coarticulation was investigated in Thai-speaking normal and brain-damaged adults. A total of 47 speakers (10 young normal, 10 old normal, 13 nonaphasic right-brain-damaged patients, 14 left-brain-damaged aphasic patients, 9 fluent, 5 nonfluent) produced all 25 possible sequences of two tones from the five lexical tones of Thai embedded in a carrier sentence.F₀contours were analyzed in terms of height and slope at 10% intervals throughout the duration of the two syllables. Acoustic analysis revealed that anticipatory and perseverative tonal coarticulation of tones was markedly reduced in left fluent aphasics, totally absent in left nonfluent aphasics, but reasonably intact in right hemisphere patients. Findings are interpreted to highlight the nature of speech disturbances in nonfluent and fluent aphasia, hemispheric specialization for tone, and tonal coarticulation in Thai.     

Prosodic disturbance in aphasia: Vowel length in Thai

The aim of this study is to determine to what extent a phonologically contrastive function of the prosodic feature of length is resistant to impairment in aphasia. The language chosen for investigation is Thai, a language which contrasts short and long vowels. Subjects included two Broca aphasics, one transcortical motor aphasic, one Wernicke aphasic, one conduction aphasic, one nonaphasic right-brain-damaged patient, one nonaphasic cerebellar dysarthric patient, and five normal controls. The subjects read a list of words containing short and long vowels. Vowel durations were measured from spectrograms. The results showed that the timing of vowel duration for signaling the contrast between short and long vowels remains relatively intact in nonfluent as well as fluent aphasic patients. These data are brought to bear on issues concerning the specialization of the left hemisphere for temporal processing, the contribution of the right hemisphere to the processing of nonaffective components of prosody, the nature of prosodic disturbance in Broca's aphasia and cerebellar dysarthria, and the separate disruption of prosodic features.     

Nasal consonant production in Broca's and Wernicke's aphasics: speech deficits and neuroanatomical correlates

The present study investigated the articulatory implementation deficits of Broca's and Wernicke's aphasics and their potential neuroanatomical correlates. Five Broca's aphasics, two Wernicke's aphasics, and four age-matched normal speakers produced consonant-vowel-(consonant) real word tokens consisting of [m, n] followed by [i, e, a, o, u]. Three acoustic measures were analyzed corresponding to different properties of articulatory implementation: murmur duration (a measure of timing), amplitude of the first harmonic at consonantal release (a measure of articulatory coordination), and murmur amplitude over time (a measure of laryngeal control). Results showed that Broca's aphasics displayed impairments in all of these parameters, whereas Wernicke's aphasics only exhibited greater variability in the production of two of the parameters. The lesion extent data showed that damage in either Broca's area or the insula cortex was not predictive of the severity of the speech output impairment. Instead, lesions in the upper and lower motor face areas and the supplementary motor area resulted in the most severe implementation impairments. For the Wernicke's aphasics, the posterior areas (superior marginal gyrus, parietal, and sensory) appear to be involved in the retrieval and encoding of lexical forms for speech production, resulting in increased variability in speech production.     

Speech timing subsequent to brain damage: effects of utterance length and complexity

Acoustic analyses of syllable durations were conducted in order to address several hypotheses concerning deficits in the control of speech timing subsequent to focal brain damage. Groups of nonfluent and fluent aphasics, right-hemisphere-damaged patients, and normal controls produced monosyllabic root syllables in medial and final position in the context of short and long sentences and syntactically simple and complex sentences. Durations of the target syllable as a proportion of the utterance were compared across contexts and groups. Somewhat surprisingly, the results revealed relatively normal temporal patterns in all subject groups, with the main exception emerging for the nonfluent aphasic patients who failed to demonstrate normal phrase-final lengthening effects. Implications of the findings for theories of temporal control in brain-damaged patients are considered.     

Linguistic and nonlinguistic priming in aphasia

Studies of real-time processing in aphasia suggest that linguistic symptoms may be due to deficits in activation dynamics rather than loss of linguistic knowledge. To investigate the domain specificity of such processing deficits, we compared performance by Italian-speaking fluent aphasics, nonfluent aphasics, and normal controls in a linguistic priming task (grammatical gender) with their performance in a color-priming task that requires no verbal mediation. Normal or larger than normal color-priming effects were demonstrated in both aphasic groups. Gender priming did not reach significance in either group, even though the patients displayed above-chance sensitivity to gender class and gender agreement in their accuracy scores. The demonstration of spared gender knowledge despite impaired gender priming underscores the utility of on-line techniques in the study of aphasia. The demonstration of spared color priming suggests that priming deficits in aphasia are either (1) specific to speech and language or (2) specific only to those sensorimotor and attentional processes that language shares with other nonlinguistic systems.     

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.     

The neurological substrates for prosodic aspects of speech

The ability to comprehend and produce the stress contrast between noun compounds and noun phrases (e.g., greenhouse vs. green house) was examined for 8 nonfluent aphasics, 7 fluent aphasics, 7 right hemisphere damaged (RHD) patients, and 22 normal controls. The aphasics performed worse than normal controls on the comprehension task, and the RHD group performed as well as normals. The ability to produce stress contrasts was tested with a sentence-reading task; acoustic measurements revealed that no nonfluent aphasic used pitch to distinguish noun compounds from phrases, but two used duration. All but one of the RHD patients and all but one of the normals produced pitch and/or duration cues. These results suggest that linguistic prosody is processed by the left hemisphere and that with brain damage the ability to produce pitch and duration cues may be dissociated at the lexical level.