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.     

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.     

Speech-related body movement in aphasia: period analysis of upper arms and head movement.

The effects of aphasia on coverbal body movement have important implications for the understanding of both normal and pathological speech processes. The related findings were often inconsistent, partly due to inherent methodological difficulties which could be reduced by the use of advanced techniques of movement monitoring (Hadar, 1991). The present study employed a new computerized system, CODA-3, which locates small prismatic markers and computes by triangulation their three-dimensional position at 100 Hz. Movement of the head and the upper arms was monitored in 15 aphasic and normal subjects engaged in speech during a naturalistic interview. Movement analysis was based on automatized identification of successive movement extrema ("period analysis") and the computation of amplitude, duration, and velocity of each period. The results showed higher incidence and amplitude of all body movement in the aphasic population. Fluent aphasics showed this particularly with "symbolic," content-bearing movements, while nonfluent aphasics were higher than controls in both symbolic and "motor" (simple and small) movements. No deficit in the internal organization of movement was seen in the aphasic population. These results indicate that aphasics increase their coverbal movement in compensation for their speech impairment: fluent aphasics compensate primarily for a symbolic impairment, while nonfluent aphasics compensate more for a motor impairment.     

A study of spelling in aphasia

To secure systematic information on spelling abilities following damage to the dominant hemisphere, a test probing performance in three modalities of response was administered to a group of aphasic patients. Except for a predictable deficit among anterior aphasics in oral spelling, anterior and posterior aphasics exhibited comparable performances on the measures of spelling. However, anterior and posterior aphasics differed from one another on the kinds of words they most accurately spelled, the errors they were prone to make, and certain strategies which they characteristically adopted. These results suggest two alternative approaches to spelling: one approach, common in posterior aphasics, entails choosing letter combinations on the basis of their customary sounds; a second approach, common among anterior aphasics, appears to rely on a partially preserved image of the word's appearance.     

The effect of an intensive behavioral program on the distribution of EEG alpha power in stutterers during the processing of verbal and visuospatial information

Prior to an intensive behavioral treatment program, stutterers showed greater than normal activation of the posterior frontal region of the right hemisphere during the performance of speech tasks. After treatment they showed increases in proportional alpha for most regions of the two cerebral hemispheres, but most markedly for the posterior frontal region of the right hemisphere for both verbal and nonverbal tasks. This increase resulted in a reversal of the previous R/L interhemispheric alpha relationships with the left posterior frontal region showing greater activation during speech after treatment. The relationship of this finding to previous findings is briefly discussed and an hypothesis of decreased inhibitory control of the right hemisphere at the posterior frontal region by the left hemisphere during speech in stutterers is proposed and briefly expounded.     

Impairments of nonverbal oral movements after left hemisphere damage: A followup analysis of errors

Acquisition of a task requiring the imitation of a series of nonverbal oral movements is most severely impaired in patients with aphasic disturbance. However, nonaphasic patients with left hemisphere damage also perform more poorly than patients with right hemisphere damage or normal control subjects. Analysis of the errors made on the multiple oral movements task reveals that left, but not right, hemisphere damage is highly associated with perseverative responses. Patients with right hemisphere damage do not differ significantly from normal control subjects in the acquisition of or in the type of errors made on the task. It is suggested that the left hemisphere plays an important role in the control of nonverbal oral movement production.     

Verbal reaction time patterns in aphasic adults: consideration for apraxia of speech

Verbal reaction time patterns were compared in aphasic adults presenting anterior and posterior left hemisphere lesions. Reaction Times were measured from simultaneous recording of the subjects' verbal responses and electromyographic activity from three oral-facial sites. Total Reaction Time was fractionated into Premotor Time and Motor Time components to assess latencies associated with motor speech planning and execution. The results suggested that only anterior lesions result in deficits in motor speech planning and/or execution while posterior lesion patients perform no differently than normal. The evidence supports traditional concepts regarding apraxia of speech as being associated with frontal lobe lesions.     

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.     

Recurrent fluent aphasia associated with a seizure focus

The relationship between dominant hemisphere seizure activity and aphasia is unclear. Although speech arrest, expressive speech problems, and comprehension difficulties have often been associated with temporal lobe seizure activity, neologistic, paraphasic speech is rare. We report a patient with seizures following encephalitis who had recurrent episodes of fluent, severely aphasic speech with impaired comprehension which correlated with continuous, high voltage spike and slow wave activity in the left temporal region. During a several-day period of intermittent electrographic seizure activity, he had fluctuating receptive aphasia, and he developed transient paranoid psychosis following treatment. We discuss the behavioral manifestations of his left temporal seizures and correlate the changing nature of his behavior with therapeutic interventions. This case, as well as a review of others, suggests that paroxysmal fluent aphasia results from a partially treated electrographic seizure focus in the dominant temporal lobe.     

The effect of response choice relatedness on pantomime and verbal recognition ability in aphasic patients

Twenty aphasic and twenty control subjects were examined on two versions of a pantomime recognition and a verbal recognition test; one version containing response choices conceptually/semantically related to target responses, the other containing unrelated response choices. The aphasic group was inferior to controls on the pantomime and verbal recognition tests, although the magnitude and consistency of the differences between aphasics and controls were greater for the pantomime test. The presence of conceptually/semantically related response choices on the pantomime recognition test significantly reduced test scores of aphasic patients, and this reduction was related to the magnitude of the effect of response choice relatedness on their verbal recognition test performance. The findings are consistent with an interpretation of aphasia as an impairment of a central symbolic ability which can affect processing for meaning in both verbal and nonverbal modes of communication.     

Analytical competence and language impairment in aphasia

Matched groups of Broca's and Wernicke's aphasics, brain-damaged patients without aphasia and chronic schizophrenics were tested in a nonverbal matching task where the subject had to indicate which of two pictures was more closely linked to a clue picture. Eight additional verbal and nonverbal reference tasks were administered. Both aphasic groups performed worse than brain-damaged controls when the identification of individual attributes or actions shared by clue and referent was required, but were unimpaired when the two had a set of referential-situational associations in common. Factor analyses resulted for both groups in two factors, one of which represents general Language Impairment. For the Broca's aphasics this factor was closely related to general organic deficit as measured by the Trail Making Test; for the Wernicke's aphasics it was associated with tasks which might be considered illustrative of analytical competence in isolating and comparing individual features of objects or concepts.     

Anticipatory coarticulation in aphasia: acoustic and perceptual data

Two experiments investigated speech motor planning in aphasia by contrasting the degree of labial and lingual anticipatory coarticulation evident in normal subjects' speech with that found in the speech of aphasic subjects. In the first experiment, Linear Predictive Coding (LPC) analyses were conducted for the initial consonants of CV [si su ti tu ki ku] and CCV [sti stu ski sku] productions by 6 normal and 10 aphasic (5 anterior, 5 posterior) subjects. For normal subjects' productions, reliable coarticulatory shift was found for almost all measurements, indicating that acoustic correlates for anticipatory coarticulation obtain for [s], [t], and [k] in a prevocalic environment, as well as when [s] is the initial consonant of a CCV syllable. The data for the aphasic subjects were statistically indistinguishable from those of the normal subject group, and there were no differences noted as a function of aphasia type. In the second experiment, a subset of the consonantal stimuli produced by the normal and aphasic subjects was presented to a group of 10 naive listeners for a vowel identification task. Listeners were able to identify the productions of all subjects at a level well above chance. In addition, small but statistically significant Group differences were observed, with the [sV], [skV], and [tV] productions by anterior aphasics showing significantly lower perceptual scores than those of normal subjects.     

Nonspeech and speech processing skills in patients with aphasia and apraxia of speech

Nonspeech and speech auditory processing skills as well as internal speech processing skills were assessed among four patients with acquired "pure" apraxia of speech, 10 with acquired aphasia, 10 with aphasia plus apraxia of speech, and 11 neurologically normal adults. Fourteen tasks were administered and performances on 68 variables were examined using both nonparametric and parametric analyses controlling for the effects of advancing age and associated hearing loss. In all cases, the "pure" apractic patients performed as normal subjects. Few differences were noted among the performances of the aphasic and aphasic-apractic subjects. Results led to three major conclusions: (1) apraxia of speech is a disorder distinct from aphasia; (2) aphasic individuals, despite locus of lesion, demonstrate disabilities for processing nonspeech and speech materials presented auditorily and for analytically evaluating speech evoked internally; and (3) aphasic individuals demonstrating similar severity levels of language impairment show similar performance patterns for these types of processing tasks, despite locus of lesion or coexistence of apraxia of speech.     

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.     

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.     

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.     

Regional cerebral blood flow patterns during verbal and nonverbal auditory activation

Current views of the relationship between audition and cerebral function suggest that increases in regional cerebral blood flow (rCBF) would occur in the superior, mid, and posterior portions of the temporal lobes, and that these changes would be more lateralized to the left hemisphere for a verbal than a nonverbal auditory task. We measured rCBF using the xenon inhalation technique in a group of healthy subjects during three conditions: (1) resting baseline, (2) auditory verbal activation (listening for word meaning), and (3) auditory nonverbal activation (listening for reduction of intensity in a series of noise bursts). Both verbal and nonverbal conditions produced highly significant increases in rCBF over the left posterior Sylvian region with a trend for verbal activation to evoke a wider area of flow increase than the nonverbal task.     

Selective deficit of conceptual structures in aphasia: Class versus thematic relations

Conceptual structures in aphasia were investigated by means of a nonverbal test. The understanding of class and thematic relationships was demonstrated to be selectively impaired according to varieties of aphasic deficit. Broca's aphasics showed difficulty evaluating a thematic relationship and did not differ from normal controls as far as class relationships were concerned. The opposite happened for Wernicke's aphasics whose defect seems to be selectively restricted to class relationships.     

Auditory event-related potential probes and behavioral measures of aphasia

This study examined the relationship between an auditory event-related potential probe technique measure of differential hemispheric processing and traditional tests of aphasia in aphasic patients. Subjects were 10 aphasic and 10 normal adult males. The results of the electrophysiological measures indicated that the aphasic subjects responded differently from the normal group particularly when the task required processing of verbal information. During the verbal task the aphasic group showed higher amplitude right hemisphere responses as compared to left. The normal group showed little hemispheric task related asymmetries. The pattern of electrical asymmetry in the aphasic group seems to be an indicator of severity as measured by traditional aphasia examinations.     

Left hemispheric interference with nonverbal performance in aphasics: comparison with data from split-brain studies

Two nonverbal tasks (Nebes' Figural Unification Test and Arc-Circle Matching Task) were given to 10 aphasic patients and 10 normal controls. Observations in split-brain patients have shown that the right hemisphere performs almost normally on these tasks while the left hemisphere fails completely. Left and right hand performances of aphasics and controls were compared with those of split-brain patients as reported in the literature. In the Figural Unification Test the aphasics' left hand performance was significantly poorer than that of split-brain patients. This is interpreted as an effect of left hemispheric interference with right hemispheric nonverbal performance. The lack of a similar impairment of left hand performance in the Arc-Circle Matching Task suggests that this interference is only provoked by tasks which, due to the possible verbalization of stimulus material, tend to stimulate left hemispheric activity.