Selective involvement of the auditory-verbal modality in an acquired communication disorder: Benefit from sign language therapy

A 39-year-old female suffered bitemporal infarctions and exhibited an unusual behavioral syndrome of muteness and impaired auditory comprehension, with milder aphasic deficits in reading and writing. The anatomic basis of this modality-selective communication disorder appeared to involve both peripheral perceptual and motor as well as “central” language mechanisms. The patient's ability to communicate was greatly aided by instruction in Amerind and Ameslan Sign Language, in which she learned more than 100 signs. Patients whose acquired language deficits spare modalities of input or output may be ideal candidates for sign language therapy.     

Estimating response time hazard functions: An exposition and extension

The hazard function of a response time distribution describes the temporal dimension of a response process and completely characterizes the distribution. The function can be estimated by a quadratic spline which is constrained to have one of a number of simple functional forms. The estimator can also be employed when the response time is an unobserved component in a parallel or serial pair of processes.     

Longitudinal neuropsychological report of aphasia following left-subcortical hemorrhage

The neuropsychological assessments of a patient with language disturbance following left thalamic-putaminal hemorrhage over a $\text{2}\text{1}\text{2}\text{-}\text{year}$ period are presented together with premorbid measures of performance. Findings indicate that behavioral deficits which are both linguistic and nonlinguistic in nature differ from cortical aphasic syndromes in symptomatology and recovery course. The deficit pattern is also unlike that in other reported cases of left-subcortical lesions. Persistent dysarthria with fluent speech, limitation of verbal span and repetition, agraphia and anomia, and disturbances in self-regulation of behavior were noted, in addition to recovery of an initially severe auditory comprehension deficit. A distinguishing feature of this case was the relative preservation of reading comprehension in all four assessments.     

Semantic aphasia: A neglected entity

Three cases of semantic aphasia are reported. Computerized brain tomography showed bilateral temporo-parieto-occipital junction hemorrhages in one patient, and left parieto-occipital junction infarctions in the other two patients. The auditory comprehension defect of the three patients was characterized by preserved understanding of single words and impaired understanding of grammatically complex constructions. It is suggested that this comprehension defect reflects an inability to fully grasp the meaning of words and grammatical constructions imbued with spatial or quasi-spatial significance. Each of the three patients showed a complex spatial disorder that included constructional apraxia, spatial agnosia, and elements of Gerstmann's syndrome. The aphasic as well as the spatial disorder of semantic aphasics may be manifestations of a common defect in the perception of spatial relationships produced by left temporo-parieto-occipital region damage.     

A modern assessment of the basic forms of aphasia

A brief survey of the field of aphasia is presented. Many of the facts described in the neurological classics remain valid, but the interpretation of these facts must be altered. The basic principles of aphasia are reassessed in the light of neuropsychology. Neuropsychological analysis shows sensory (acoustico-gnostic) aphasia to be based upon an impairment in phonemic hearing. Motor aphasia breaks down into afferent (kinesthetic) and efferent (kinetic) aphasia. The former is based upon an impaired kinesthetic input into the speech functions, which results in a special type of oral apraxia. Efferent (kinetic) aphasia is based upon a breakdown in the kinetic organization of speech motor acts. Nominative (amnestic) aphasia consists of a number of forms, each based on either a weakness of visual or auditory analysis or difficulty in selection between evoked memory traces. “Transcortical motor aphasia” proves to be either perseverative aphasia, i.e., aphasia in which the dynamics of plasticity are impaired, or the result of the impairment of internal speech. The basic defect underlying “conduction” aphasia is beginning to be understood as a weakened acoustico-gnostic function or difficulties in retarding sideline associations.     

The selective impairment of phonological processing: A case study

A case study is reported of an aphasic patient with fluent speech and markedly superior comprehension of written vs. spoken words. Results of extensive testing supported the hypothesis that the patient suffers from a phonological processing deficit that affects performance in all tasks that require the generation of a phonological code. This selective deficit is interpreted as the underlying cause of diverse symptoms such as asyntactic comprehension of written sentences, the commission of spelling errors in writing, and the production of literal paraphasias and neologisms in spontaneous speech. Alternative possibilities for the classification of this patient are discussed.     

Regional cerebral blood flow response to recognition memory versus semantic classification tasks

Two randomly assigned groups, N = 7 each, of neurologically normal patients were composed. One group, RM, had regional cerebral blood flow measurements during a recognition memory probe test; the other group, SC, had rCBF measurements during a semantic classification task, using the same stimulus and response features as the RM task. Thus, the groups differed only in the cognitive instruction they were executing. The RM group showed a significantly lower change from resting baseline to activation, in mean left hemisphere initial slope index, than did the SC group. The RM group, but not the SC group, showed a significant inverse correlation between occipital flow and accuracy of memory performance as indicated by d′. Correlations between age and hemispheric initial slope index, and between homologous left and right hemisphere sites, were also described. The results are considered to support an anatomical basis for the distinction between episodic and semantic memory and to suggest that occipital flow may diminish with accurate memory performance because of an upstream demand of blood in the medial temporal lobes.     

Patterns of regional cerebral blood flow during attempted reading aloud by stutterers both on and off haloperidol medication: Evidence for inadequate left frontal activation during stuttering

Two stutterers, both recent college graduates, were subjected to regional cerebral blood flow measurements while attempting to read aloud. Each one received two measurements, one of which was under the influence of haloperidol, 3 mg daily. Both subjects showed improvement on medication, allowing a stuttering versus essentially no stuttering comparisons for each subject. Both subjects showed higher Broca's area flow in the right compared to the left hemisphere, during stuttering. Both showed higher Wernicke's area flow in the left compared to the right hemisphere, however, during stuttering. During reading aloud without stuttering, however, the Brocas's area flows were reversed, now showing a left hemisphere advantage. The results were interpreted as consistent with H. M. Sussman and P. F. MacNeilage's (1975, Neuropsychologia, 13, 19–26) proposal that stutterers exhibit conventional left cerebral dominance for speech reception, but inadequate left cerebral dominance for speech production.     

Production deficits in aphasia: A voice-onset time analysis

An experimental study was conducted to examine phonetic and phonemic deficits in the speech production of aphasics. Subjects included four Broca's aphasics, four Conduction aphasics, five Wernicke's aphasics, one nonaphasic dysarthric patient, and four normal controls. The subjects read a list of words containing word-initial stop consonants which were subsequently measured acoustically for voice-onset time. The results showed that Broca's aphasics exhibit a more severe production disorder than Conduction aphasics who in turn exhibit a more severe disorder than Wernicke's aphasics, in accord with clinical observations. In addition, although Broca's aphasics produced both phonetic and phonemic errors, the results showed that they have a pervasive phonetic disorder which affects their correct target productions as well as the total number of phonetic errors produced. This deficit however seems to be a speech deficit rather than a low-level motor control problem. In contrast, the Wernicke's aphasics show a deficit characterized by isolated phonemic mistargeting errors. Finally, the pattern of productions for the Conduction aphasics indicates that some patients show a predominantly phonetic disorder similar to the Broca's aphasics and others show predominantly a phonemic disorder similar to the Wernicke's aphasics.     

Defects of immediate memory in Broca's and conduction aphasia

It has been suggested that the repetition defect seen in conduction aphasia is caused by an auditory immediate memory defect. The purposes of this study were the following: to ascertain whether the finding of an auditory immediate memory defect in conduction aphasia could be replicated, to ascertain whether Broca's aphasics have a similar type of immediate memory defect, and to ascertain whether a relationship exists between immediate memory and comprehension of spoken language. Digits were either spoken or presented visually to Broca's and conduction aphasics. An analysis of span scores reveals that within each group there were no significant differences between the modes of presentation or the response modes. There were no significant differences between the aphasic groups. Comprehension of spoken language significantly correlated with digit span scores.     

Regional cerebral blood flow response during rest and memory activation in a patient with global amnesia

A college professor with a classical amnesic syndrome is described. He has a WAIS IQ of 130, but dramatic memory loss for episodes ranging from a few seconds ago all the way back to portions of his childhood. The amnesia was of sudden onset, 2 years prior to the current memory tests and regional cerebral blood flow measurements. The etiology is believed, though not conclusively proven, to be medial thalamic infarction. rCBF measurements were taken on six separate occasions, four resting baseline, one memory activation, using the previous procedure of Wood, Taylor, et al., and one carbon dioxide activation. The resting baseline showed extremely low flows throughout the cortex, with some hyperfrontal response on the first baseline. With CO₂ activation, however, there was brisk, uniform reactivity, with all sites showing increased flow. This suggested that there were no prominent areas of impaired vasomotor control or probable ischemic damage in the cortical surface. During memory activation, there was also a generalized increase in flow, especially in the frontal areas. This was in sharp contrast to the pattern for normals, described by Wood, Taylor, et al., which shows a slight overall decrease in flow from baseline to memory activation. The results are interpreted in light of Talland's proposal that the amnesic syndrome reflects an arousal failure, with premature closure and shutdown of memory processing, especially at retrieval. Here the arousal failure is interpreted as an inadequate restriction or focusing of cortical activation, with resulting pathologically diffuse flow increases.     

Classification and perceptual development: Exploring issues about integrality and differential sensitivity

Pre- and elementary-school children, 4 and 11 years of age, were given a classification task similar to those given in research testing an account that posits a developmental shift from integral to separable perception. The development of perceptual sensitivity and its role in determining similarity and dimensional classifications was assessed with the variables of predisposed and distinctiveness-based salience. The results indicated that the level of perceptual sensitivity to the dimensions in the task determined the frequency of types of classifications. Children in both age groups made both kinds of critical classifications as a function of predisposed and distinctiveness-based salience.     

Semantic processing in aphasia: Evidence from an auditory lexical decision task

W. Milberg and S. E. Blumstein (1981, Brain and Language 14, 371–385) demonstrated semantic facilitation effects in a visual lexical decision task administered to Wernicke and other aphasics with severe comprehension deficits. In an attempt to explore the generalizability of these findings in a task where the acoustic-phonetic system could not be bypassed to access meaning, Wernicke's, Global, Broca's, and Conduction aphasics were administered a lexical decision task in the auditory modality. The patients were also given a simple semantic judgment task using the word pairs from the lexical decision task. The aphasic patients showed evidence of semantic facilitation whether they were categorized by diagnostic group or comprehension level. Performance of the semantic judgment task correlated with the severity of auditory comprehension deficits, whereas the consistency of the semantic facilitation effect did not. Even patients with severe comprehension deficits showed semantic facilitation. These results decrease the likelihood that auditory comprehension deficits are due to semantic organization per se and increase the likelihood that the deficits lie in one of the many processes involved in access to that information.     

Interactive effects of generalized and situational expectancies on the arousal of cognitive and emotional components of social anxiety

This study examined the arousal of social anxiety in an interview setting as a function of anticipated self-disclosure. Of 88 college students who completed the Social Avoidance and Distress (SAD) scale and other measures of social anxiety, self-disclosure, need to affiliate, and interpersonal trust, 24 volunteered for the interview. During the interview, both components of anxiety (worry and emotionality) were affected by expectancy conditions, and emotionality was higher for high- than for low-SAD subjects. The prediction of an interaction between SAD level and expectancy condition on worry was confirmed: only high-SAD subjects exposed to the negative-expectancy condition experienced significant elevations in worry. Though social anxiety and self-disclosure measures correlated negatively, anxiety did not affect self-disclosure during the interview.     

An investigation of repetition and language processing in a case of conduction aphasia

A study is reported of a single case of conduction aphasia. A battery of tasks designed to investigate the parameters of the patient's severe repetition deficit is supplemented by tests of several language functions. The results provide extensive information on a wide range of the patient's language abilities and are used to evaluate the adequacy of four models that have been offered to account for conduction aphasia. An argument is made in support of the suggestion that the syndrome of conduction aphasia should be divided into two subgroups based on patients' ability to select and realize phonemes in speech output. It is concluded that the best explanation for the disorder of patients with repetition deficit but without significant speech output problems is the hypothesis that repetition ability is compromised by a pathological limitation of auditory-verbal short-term memory. This hypothesis is extended to account for the pattern of results obtained in the language tasks.     

Reading and listening comprehension in Broca's aphasia: Lexical versus syntactical errors

Ten agrammatic Broca's aphasics were presented with a series of four picture plates together with a spoken or written sentence stimulus. All sentence stimuli were of the structure, the + N + is/are + V + ing + the + N. The four pictures on each stimulus plate represented (a) the correct response, (b) a reversal of the stimulus sentence subject and object, (c) a change in the number of the subject of the stimulus sentence, and (d) a change in one of the major lexical items of the stimulus sentence. Subjects selected the correct picture most often. When they erred, they usually selected a subject-object reversal. Number errors were less frequent, and the patients seldom selected a change in major lexical item. This pattern occurred with both written and spoken sentences. These results were interpreted as reflecting the dependence of agrammatic Broca's aphasics on the semantic interpretation of the lexicon for decoding sentences in the face of deficits in syntactical-grammatical interpretation, irrespective of comprehension modality.     

Alexia without agraphia: An experimental case study

A 51-year-old right-handed male experienced reading difficulty and an upper right visual field cut after a head injury. The patient's letter naming was impaired and word naming was painstakingly slow. Words were decoded in a letter by letter sequence and performance varied directly with word length. Apart from his reading difficulties the patient was linguistically competent. He was sensitive to manipulations of word frequency and orthographic regularity. He wrote spontaneously and could identify the written counterpart to a spoken word with relative ease. Computerized axial tomography revealed damage to the posterior temporal-parietal region of the left hemisphere.     

Linguistic meaning related differences in evoked potential topography: English, Swiss-German, and imagined

Functionally different neural populations for processing different categories of word meaníng are suggested by the topography of event-related EEG scale-field distributions. Noun and verb meanings of English and Swiss-German homophones produced differences in anterior-posterior topography during the first 300 to 350 msec of the response. Similar results were found for a degraded-speech stimulus when subjects imagined noun and verb meanings. Anterior—posterior scalp-field differences appeared both in an analysis of the positions of field maximal and minimal values; and in principal component analysis of ERPs.