Some aspects of phonological impairment in aphasia

The relationships between expressive and receptive phonemic disorders and between disturbances of phoneme processing and general disorders of auditory comprehension were studied in 69 aphasic patients, by means of a phoneme discrimination test and of a standard aphasia battery. A significant but incomplete correlation between disorders of phonemic output and of phoneme analysis was found. The view is put forth that in some patients only phoneme encoding or decoding is disturbed, whereas in others a central level of phoneme processing is impaired. A significant but partial correlation was also found between disorders of phonological analysis and general disorders of auditory comprehension. This supports the view that, besides sequential phonological analysis, other processes operate in auditory comprehension.     

Anomia with and without lexical comprehension disorders

Anomic patients are usually described as free from language comprehension disorders, but the status of lexical comprehension in anomia is still controversial. Most anomic patients are impaired on tasks of semantic-lexical discrimination, but some of them do not present clear signs of semantic-lexical deficit at the receptive level. The aim of the present research was to elucidate the nature of word-finding disturbances by contrasting results obtained by anomic patients with and without lexical comprehension disorders on a number of variables, namely severity of anomia, implicit knowledge of words that patients failed to name, presence of verbal-semantic paraphasias, and scores obtained on a test of phoneme discrimination and on the "Token Test." The results of our investigation seem to suggest that there are two types of anomia, caused by the impairment of two different sets of mechanisms. In "purely expressive anomia" the locus of defect seems to be near to the stage in which the selected lexical item is specified into the appropriate phonological form. In "anomia with lexical comprehension disturbances" the locus of defect seems to be much deeper within the lexicon, so that the semantic disorder affects both the expressive and the receptive levels in a roughly comparable manner.     

Phonemic imperception in aphasia

This study investigated characteristics of 14 aphasics with impaired phoneme discrimination identified from a population of 100 patients with left hemisphere lesions. All patients with impaired phoneme discrimination were significantly impaired in aural comprehension, but many showed intact sound recognition and some showed normal reading comprehension. Defects in phoneme discrimination were typically seen in the acute stage of aphasia resulting from stroke; and in most instances, defects in phoneme discrimination were no longer apparent 4 months postonset. All patients who recovered normal phoneme discrimination also made significant improvement in aural comprehension. The findings support the concept that some aural comprehension defects result from a specific disturbance in phoneme discrimination.     

Discrimination of voice versus place contrasts in aphasia

A phoneme discrimination test based upon CCVC (consonant-consonant-vowel-consonant) syllables was administered to 36 aphasics, 91 brain-damaged subjects, and 42 normal controls, in normal listening conditions. Errors in the discrimination of voice and place contrasts were determined, and the scores (voice-minus-place errors) obtained by the four experimental groups were compared statistically. Aphasic patients, when compared with the other groups, show a greater difficulty in discriminating place than voice contrasts. Some implications of these findings are discussed.     

Auditory perception of speech and speech sounds in recent and recovered cases of aphasia

Auditory perception of speech and speech sounds was examined in three groups of patients with cerebral damage in the dominant hemisphere. Two groups consisted of brain-injured war veterans, one group of patients with high-frequency hearing loss and the other, a group of patients with a flat hearing loss. The third group consisted of patients with recent cerebral infarcts due to vascular occlusion of the middle cerebral and internal carotid artery. Word and phoneme discrimination as well as phoneme confusions in incorrect responses were analyzed from conventional speech audiometry tests with bisyllabic Finnish words fed close to the speech reception threshold of the patient. The results were compared with those of a control group with no cerebral disorders and normal hearing. The speech discrimination scores of veterans with high-frequency hearing loss and patients with recent cerebral infarcts were some 15–20% lower than those of controls or veterans with flat hearing loss. Speech sound feature discrimination, analyzed in terms of place of articulation and distinctive features, was distorted especially in cases of recent cerebral infarcts, whereas general information transmission of phonemes was more impaired in patients with high-frequency hearing loss.     

Disorders of classificatory activity in aphasia

Two nonverbal tasks of classificatory activity ("class inclusion" and "class intersection") were administered to 46 aphasics, 28 normal controls, 19 nonaphasic left-brain-damaged and 17 right-hemisphere-damaged patients in order to study if aphasic patients are more impaired than nonaphasic brain-damaged patients on these two tasks of elementary logic and if a relationship exists within the aphasic patients between inability to perform the tasks of classifiactory activity and impairment of the semantic-lexical level of integration of language. Results were for the most part in line with expectations because aphasics scored worse than normal controls and nonaphasic brain-damaged patients (even if the difference reached the level of statistical significance only on the test of "class intersection") and within the aphasic patients the worst results were obtained by subjects presenting clear signs of semantic-lexical disintegration.     

Comprehension of symbolic gestures in aphasia

One-hundred-and-twenty-eight patients with unilateral hemispheric damage (53 aphasics, 26 nonaphasic left, and 49 right brain-damaged patients) and 25 normal controls were given a test of symbolic gesture comprehension and other tests of verbal comprehension and of reproduction of symbolic gestures. On the test of symbolic gesture interpretation aphasic patients performed significantly worse than any other group of brain-damaged patients. Within the aphasic patients the inability to understand the meaning of symbolic gestures was highly related to the number of semantic errors obtained at a verbal comprehension test. On the contrary, only a mild relationship was found between comprehension and reproduction of symbolic gestures. Some implications of these findings are discussed.     

Retention of verbal information by rehearsal in relation to the fluency of verbal output in aphasia

The purpose of the present study was to determine if aphasic subject groups differentiated by the fluency of their verbal output employed rehearsal as a strategy for maintaining verbally coded information in primary memory. A task based upon the Brown-Peterson paradigm was administered to 10 fluent aphasic patients, 10 nonfluent aphasic patients, 10 right-brain-damaged patients, and 10 nonneurological patients. The findings indicate that the nonfluent aphasic patients did not rehearse the verbal information while the fluent aphasic, right-brain-damaged, and nonneurological patients did rehearse. In addition, both fluent and nonfluent aphasic patients encoded significantly less information into the memory system initially and performed worse on the task overall than right-brain-damaged and nonneurological patients.     

Development of comprehension of sentences with “because” or “if”

The comprehension of sentences with “because” or “if” was investigated in children aged 2;9–11;11. Imitation, comprehension (choosing one of two picture sequences to go with a sentence), recognition (judging sentences with connective or structure differences as heard before or not), and synonymy (judging equivalence of meaning in sentences with different connectives or structures) tasks were administered, along with logical ordering, reversibility, and classification tasks. Above-chance responding in the comprehension task occurred by age 8, and in recognition and synonymy by age 10. Cognitive performance predicted 28.4% of the variance in the linguistic scores and cognitive success was concurrent with or preceded linguistic success. Comprehension of “because” and “if” appears to develop gradually, and is related to the development of certain operative rules.     

What is right with “deep” dyslexic patients?

Two aphasic adults with a specific acquired dyslexia were given tests requiring the processing of written words and sentences. Despite the general severity of the patients' deficits, some aspects of such processing appear to be relatively well preserved. The patients have particular difficulty reading aloud function words and abstract words; yet in word/nonword discrimination tests, both patients showed normal recognition of function words and one showed normal performance with abstract words. The patients do have a deficit in comprehension of visually presented words and sentences; yet their performance on comprehension tests was considerable and, moreover, showed meaningful relationships with their ability to read aloud.     

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.     

Getting ready for reading: A follow‐up study of inner city second language learners at the end of Key Stage 1

Background: A previous study (Stuart, 1999) showed that early phoneme awareness and phonics teaching improved reading and spelling ability in inner‐city schoolchildren in Key Stage 1, most of whom were learning English as a second language. Aims: The present study, a follow‐up of these children at the end of Key Stage 1, addresses four main questions: (1) Are these improvements maintained to the end of Key Stage 1? (2) Are different patterns of cognitive process evident in the word recognition skills of phonics trained versus untrained children? (3) Do the phonics trained children now also show a significant advantage in reading comprehension? (4) Are there differences in amount of reading, in self‐concept as readers and in oral vocabulary development between phonics trained and untrained children? Relationships between reading and spelling ages and Key Stage 1 SATs levels are also explored. Sample: Data are reported from 101 seven‐year‐olds (85 of whom were second language learners) remaining from the original 112 children reported on previously. Method: Children were tested on four standardized tests of reading, spelling and vocabulary, and on a further six experimental tests of phoneme segmentation, grapheme‐phoneme correspondence knowledge, regular, exception and nonword reading, author recognition and reading self‐concept. Results: Lasting influences of early phoneme awareness and phonics teaching on phoneme awareness, grapheme‐phoneme correspondence knowledge, word reading and spelling were found. Part of the previously untrained group had now received structured phonics teaching, and were therefore treated as a third (late trained) group. Early and late‐trained groups showed similar levels of attainment and similar cognitive processing patterns, which were different from the untrained group. However, there were no influences of training on reading comprehension, self‐concept or oral vocabulary. Conclusions: Early phoneme awareness and phonics training efficiently accelerates the word recognition and spelling skills of first and second language learners alike. However, this is not sufficient to bootstrap the development of language comprehension in the second language learners. Further research is needed into the kinds of language teaching that will best develop their oral and written language comprehension.     

Text comprehension in aphasia

The semantic and pragmatic strategies in the comprehension of spoken texts are investigated in four subgroups of aphasic patients and in normal and brain-damaged controls. Short texts of similar linguistic structure were read to the subjects, who were required to choose the picture, from a multiple choice set of five, that was appropriate to the story. Besides a picture showing the main event of the story, one picture depicted the literal sense of a metaphorical comment, and the others misrepresented semantic functions expressed in the text. With respect to these types of responses, both aphasics and controls exhibited the same pattern of reaction. It is concluded that the redundancy of texts makes up for the difficulties aphasics have in comprehending isolated words and sentences.     

Decision processes during sentence comprehension: Effects of surface structure reconsidered

Previous experiments have yielded conflicting results concerning the utility of relative pronouns as cues to the deep structure underlying self-embedded (SE) sentences. The present study investigated the usefulness of this cue. At the same time, it compared the relative sensitivity of two measures of sentence-comprehension difficulty: paraphrasing and phoneme monitoring. Forty Ss heard SE sentences, one-half of which had the relative pronouns deleted. The presence or absence of the relative pronouns in a particular sentence was counterbalanced across groups. The Ss also heard right-branching sentences. It was found that presence of the relative pronouns led to significantly faster phoneme monitoring times and to marginally better paraphrasing (i.e., to better comprehension) in the SE sentences. It was concluded that relative pronouns are effective cues and, further, that the phoneme monitoring technique is a better index of comprehension difficulty than the paraphrasing technique. Reasons for the previous experimental discrepancies were discussed.     

Acoustic cues for the perception of place of articulation in aphasia

Two experiments assessed the abilities of aphasic patients and nonaphasic controls to perceive place of articulation in stop consonants. Experiment I explored labeling and discrimination of [ba, da, ga] continua varying in formant transitions with or without an appropriate burst onset appended to the transitions. Results showed general difficulty in perceiving place of articulation for the aphasic patients. Regardless of diagnostic category or auditory language comprehension score, discrimination ability was independent of labeling ability, and discrimination functions were similar to normals even in the context of failure to reliably label the stimuli. Further there was less variability in performance for stimuli with bursts than without bursts. Experiment II measured the effects of lengthening the formant transitions on perception of place of articulation in stop consonants and on the perception of auditory analogs to the speech stimuli. Lengthening the transitions failed to improve performance for either the speech or nonspeech stimuli, and in some cases, reduced performance level. No correlation was observed between the patient's ability to perceive the speech and nonspeech stimuli.     

Unexpected reading precocity in a normal preschooler: implications for hyperlexia

This is a case study of a left-handed, preschool boy of superior intelligence who read very early and at a level well beyond what his IQ would predict. He is developmentally normal with no signs of autism or related disorders. His reading age was 9.3 at age 2-11 and 11.2 at 4-2; these levels are considerably beyond what would be predicted by his IQ or language age. He was able to read nonwords and both regular and irregular words equally well, indicating his mechanisms of lexical access in reading are similar to those of normal readers. Unlike classical hyperlexics, his reading comprehension for both single words and sentences was well above age level. When his precocious reading first appeared, he was also advanced in reading-related linguistic skills, such as phoneme awareness, auditory verbal short-term memory, and word retrieval, but not in visuospatial skills. These results imply that neither pathological language and/or social development, nor pathological variation in the normal mechanisms of lexical access in reading are necessary causes for reading precocity in early childhood. A model for integrating subtypes of precocious readers with subtypes of normal and dyslexic readers is proposed.     

Identifying the speech codes

Models of speech processing typically assume that speech is represented by a succession of codes. In this paper we argue for the psychological validity of a prelexical (phonetic) code and for a postlexical (phonological) code. Whereas phonetic codes are computed directly from an analysis of input acoustic information, phonological codes are derived from information made available subsequent to the perception of higher order (word) units. The results of four experiments described here indicate that listeners can gain access to, or identify, entities at both of these levels. In these studies listeners were presented with sentences and were asked to respond when a particular word-initial target phoneme was detected (phoneme monitoring). In the first three experiments speed of lexical access was manipulated by varying the lexical status (word/nonword) or frequency (high/low) of a word in the critical sentences. Reaction times (RTs) to target phonemes were unaffected by these variables when the target phoneme was on the manipulated word. On the other hand, RTs were substantially affected when the target-bearing word was immediately after the manipulated word. These studies demonstrate that listeners can respond to the prelexical phonetic code. Experiment IV manipulated the transitional probability (high/low) of the target-bearing word and the comprehension test administered to subjects. The results suggest that listeners are more likely to respond to the postlexical phonological code when contextual constraints are present. The comprehension tests did not appear to affect the code to which listeners responded. A “Dual Code” hypothesis is presented to account for the reported findings. According to this hypothesis, listeners can respond to either the phonetic or the phonological code, and various factors (e.g., contextual constraints, memory load, clarity of the input speech signal) influence in predictable ways the code that will be responded to. The Dual Code hypothesis is also used to account for and integrate data gathered with other experimental tasks and to make predictions about the outcome of further studies.     

Sentence comprehension and relative pronouns

Doubly self-embedded sentences, differing only in whether the relative pronouns were present or deleted, were presented to two groups of Ss who were required to respond to a word beginning with a particular letter in each sentence and to paraphrase the sentence. The results of both the phoneme monitor task and the paraphrase task indicated that comprehension was better when the relative pronouns were present than when they were deleted. These results are consistent with earlier results for the paraphrase task but are not consistent with earlier results for the phoneme monitor task. Possible reasons for the inconsistency were considered. It was concluded that the phoneme monitor task does reflect comprehension difficulty in a manner consistent with the paraphrase task and that deleting the relative pronouns does make comprehending self-embedded sentences more difficult.     

Organization of and access to semantic memory in aphasia

Previous experiments with picture sorting and matching tasks have shown aphasics to give more deviant responses than controls when decisions require the identification of single features of concepts, whereas their responses are close to normal whenever decisions have to be based on the relative overlap of broad associative fields. The present experiment was designed to compare picture matching based on single features (property verification) with picture matching based on category membership (category verification). Fifty-five aphasics (14 amnesics, 18 Brocas, 13 Wernickes, 10 global aphasics) and 29 right-brain-damaged control patients served as subjects. Aphasics were poorer than right hemisphere controls on property as well as on category sortings, especially when the sorting criterion was not a dominant property of the object or when the object in question was not a typical member of the criterion category. Contrary to other studies, the "semantic distance" variable did not differentially affect Brocas as compared to Wernickes aphasics. Verbal labels denoting the sorting criterion and added to the picture presentation did not affect the performance of the right hemisphere controls but significantly improved that of the aphasics.     

Discrimination between safe and unsafe stimuli mediates the relationship between trait anxiety and return of fear

Individuals with anxiety disorders show deficits in the discrimination between a cue that predicts an aversive outcome and a safe stimulus that predicts the absence of that outcome. This impairment has been linked to increased spontaneous recovery of fear following extinction, however it is unknown if there is a link between discrimination and return of fear in a novel context (i.e. context renewal). It is also unknown if impaired discrimination mediates the relationship between trait anxiety and either spontaneous recovery or context renewal. The present study used a differential fear conditioning paradigm to examine the relationships between trait anxiety, discrimination learning, spontaneous recovery and context renewal in healthy volunteers. Fear learning was assessed using continuous ratings of US expectancy and subjective ratings of fear. Discrimination mediated the relationships between trait anxiety and both spontaneous recovery and context renewal such that elevated trait anxiety was associated with poorer discrimination, which in turn was associated with increased fear at test phases. Results are discussed in terms of the genesis and maintenance of anxiety disorders.