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PubMed1997

Speed of lexical activation in nonfluent Broca's aphasia and fluent Wernicke's aphasia.

Rapid, automatic access to lexical/semantic knowledge is critical in supporting the tight temporal constraints of on-line sentence comprehension. Based on findings of "abnormal" lexical priming in nonfluent aphasics, the question of disrupted automatic lexical activation has been the focus of many recent efforts to understand their impaired sentence comprehension capabilities. The picture that emerges from this literature is, however, unclear. Nonfluent Broca's aphasic patients show inconsistent, not absent, lexical priming, and there is little consensus about the conditions under which they do and do not prime. The most parsimonious explanation for the variable findings from priming studies to date is that the primary disturbance in Broca's lexical activation has something to do with speed of activation. Broca's aphasic patients prime when sufficient time is allowed for activation to spread among associates. To examine this "slowed activation" hypothesis, the time course of lexical activation was examined using a list priming paradigm. Temporal delays between successive words ranged from 300 to 2100 msec. One nonfluent Broca's aphasic patient and one fluent Wernicke's patient were tested. Both patients displayed abnormal priming patterns, though of different sorts. In contrast to elderly subjects, who prime at relatively short interstimulus intervals (ISIs) beginning at 500 msec, the Broca's aphasic subject showed reliable automatic priming but only at a long ISI of 1500 msec. That is, this subject retained the ability to access lexical information automatically if allowed sufficient time to do so, a finding that may help explain disrupted comprehension of normally rapid conversational speech. The Wernicke's aphasic subject, in contrast, showed normally rapid initial activation but continued to show priming over an abnormally long range of delays, from 300 msec through 1100 msec. This protracted priming suggests failure to dampen activation and might explain the semantic confusion exhibited by fluent Wernicke's patients.

Aphasia, Broca↗

PubMed2001

Procedural learning in Broca's aphasia: dissociation between the implicit acquisition of spatio-motor and phoneme sequences.

Procedural learning of spatio-motor and phoneme sequences was investigated in patients with Broca's and Wernicke's aphasia and age-matched controls. In Experiment 1, participants performed a standard serial reaction task (SRT) in which they manually responded to a repeating sequence of stimulus locations. Both Broca's and Wernicke's aphasics showed intact sequence learning, as indicated by a reliable response time (RT) cost when the repeating sequence was switched to a random sequence. In Experiment 2, Broca's aphasics and controls performed a new serial search task (SST), which allowed us to investigate the learning of a spatio-motor sequence and a phoneme sequence independently from each other. On each trial, four letters were presented visually, followed by a single auditorily presented letter. Participants had to press one of four response keys to indicate the location of the auditory letter in the visual display. The arrangement of the visual letters was changed from trial to trial such that either the key-presses or the auditory letters followed a repeating pattern, while the other sequence was random. While controls learned both the key-press and the phoneme sequences, Broca's aphasics were selectively impaired in learning the phoneme sequence. This dissociation between learning of spatio-motor and phoneme sequences supports the assumption that partially separable brain systems are involved in procedural learning of different types of sequential structures.

Adult↗

PubMed1997

Temporal processing disorders in patients with Broca's aphasia.

We report an association between a language deficit following brain lesion and a new strategy in temporal integration. Patients with different brain lesions mentally grouped sequences of identical acoustic stimuli generated at various frequencies. They were asked while listening to the stimuli to accentuate every second, third or other stimulus to create an individual rhythmic pattern. After each sequence patients reported how many stimuli they had united into a perceptual unit. The integration interval was defined as the number of reported stimuli multiplied by the temporal interval between two successive stimuli. Results indicate different integration strategies depending on the lesion site, i.e. Broca's aphasics behaving differently than all other patient groups. At lower frequencies they showed longer, at higher frequencies they displayed shorter integration. From this observation we conclude that the Broca's patients acquired a new strategy because of the lesion; they relied on mental counting and less on automatic temporal integration, which is usually the case.

Adult↗

PubMed1999

How "regular" is sentence comprehension in Broca's aphasia? It depends on how you select the patients.

Grodzinsky, Piñango, Zurif, and Drai (1999) argue that a statistical analysis of pooled sentence comprehension data from published studies of Broca's aphasic patients supports the dominance of a differential pattern of performance on active and passive voice structures. They argue that these results counter a previous study in which individual patient data from published studies were analyzed. However, Grodzinsky et al. have not carried out a true test of their hypothesis, but have biased the outcome by selecting samples for analysis that support their claims.

Aphasia, Broca↗

PubMed1999

The existence of comprehension patterns in Broca's aphasia.

Berndt and Caramazza (1999) claim that Grodzinsky, Piñango, Zurif, and Drai (1999) were able to show a canonical-noncanonical difference (e.g., actives vs. passives) in the comprehension of Broca's aphasic patients only because of a patient selection bias. We show that the canonical-noncanonical comprehension pattern exists apart from any such bias, and that this pattern bears importantly on our understanding of the neuroanatomical organization of comprehension capacity at the sentence level.

Aphasia, Broca↗

PubMed1989

[Analysis of consonant substitutions by dysarthria patients and Spanish speaking Broca's aphasia patients of the La Plata area].

The speech behaviour of 11 patients with exclusively or almost exclusively phonological disorders (2 anarthical patients and 9 with aphasis of the Broca type) is being tested with an one word repetition procedure. This paper only demonstrates the analysis of the consonant substitutions and of the consonant variables under the impact of substitution. The results can be summarized as follows: 1. There is a negative correlation between the amount with which consonant phonemes are substituted and the amount of their use in normal subjects. 2. The group of phonemes which is acquired latest in speech development of the child is also influenced mostly by substitutions. 3. In the majority of substitutions we find a differentiation in one or more variables of the substituent and the substitute. 4. The variables which are influenced by substitutions show an internal hierarchy in the system of language.

Aphasia↗

PubMed1984

Immediate memory span, recognition memory for subspan series of words, and serial position effects in recognition memory for supraspan series of verbal and nonverbal items in Broca's and Wernicke's aphasia.

Four Broca's aphasics, four Wernicke's aphasics, and four matched controls were investigated on three verbal and one visual short-term memory tasks. Experiment 1 considered memory span and subspan recognition memory for verbal items and Experiment 2 assessed serial position effects in supraspan verbal recognition memory. The Broca's aphasics demonstrated verbal memory deficits, which could not be attributed to linguistic disturbances, while the verbal memory deficiencies seen with the Wernicke's aphasics could be regarded as secondary to linguistic defects. In Experiment 3, where visual recognition memory was investigated, only the Broca's aphasics showed deficient performance. The wider context of deficient mnemonic performance in aphasia is discussed.

Aged↗

PubMedDate not supplied

The representation of inflectional morphology: evidence from Broca's aphasia.

Dualistic models of inflection assume a qualitative distinction between affix-based regular forms and stored irregular forms, predicting that the two distinct mechanisms can be selectively affected in language disorders. We present data on German participle formation from 11 agrammatic Broca's aphasics which show that irregular participles can be selectively affected in agrammatism. Moreover, the distribution of errors reveals a frequency effect for irregular but not for regular participles. Both findings argue for a dualistic representation of inflection. Moreover, we want to propose a modification of dualistic models by suggesting that both regularity and irregularity are better conceived of as scalar.

Adult↗

PubMed1996

Grammaticality judgments and sentence comprehension in Parkinson's disease: a comparison with Broca's aphasia.

In order to test the hypothesis that significant linguistic deficits could be associated with predominantly subcortical dopaminergic pathways which projected to the frontal lobes (in patients with Parkinson's Disease-PD), we compared language performance in PD patients to that of Broca's aphasics with linguistic deficits. On tests of grammaticality judgements and sentence comprehension, performance by patients with Parkinson's Disease did not vary with different types of sentence structure (as was the case with the aphasics) and was instead, uniformly high (about 75% correct). Comprehension performance, however, did significantly decline in a subgroup of patients with PD who were tested when withdrawn from their dopaminergic medications. We conclude that patients with treated Parkinson's Disease evidence no selective linguistic dysfunction. When, however, they are withdrawn from dopaminergic medication language functions suffer.

Adult↗

PubMed2000

Acute aphasia in multiple sclerosis.

Acute aphasia is rare in multiple sclerosis. We describe 3 patients with multiple sclerosis who had acute exacerbations presenting as aphasias. One patient had a mixed transcortical aphasia, 1 had a transcortical motor aphasia, and 1 had a Broca aphasia. Magnetic resonance imaging scans of the brain with contrast enhancement revealed new white matter lesions in the left hemisphere in all 3 patients. Two of the 3 patients had a good response to treatment with methylprednisolone sodium succinate. Arch Neurol. 2000;57:1207-1209

Acute Disease↗

PubMedDate not supplied

[Crossed aphasia in right handed patients].

The very rare aphasia following damage to the right cerebral hemisphere in right-handed subjects is described, with a survey of the views on this problem and presentation of two cases of this so-called crossed aphasia in right-handed subjects. On one of these cases the lesion was cortico-subcortical in a part of the frontal lobe, temporal lobe and a part of the occipital lobe, with sparing of the deep structures of the right hemisphere and with clinical pattern resembling that of Broca aphasia. In the second case the lesion involved the subcortical and deep structures with destruction of the lentiform nucleus, anterior part of the internal capsule and part of the head of the caudate nucleus, and the clinical pattern resembled that of Wernicke aphasia.

Aged↗

PubMed1996

Crossed aphasia. Functional brain imaging with PET or SPECT.

OBJECTIVES: To study patients with crossed aphasia (aphasia secondary to lesions in the right hemisphere in right-handed patients) with functional brain imaging using positron emission tomography (PET) or single photon emission computed tomography (SPECT); to see whether left hemisphere structures were metabolically depressed during the acute phase and, in 1 patient, during recovery; and to review the modern literature on crossed aphasia, with special reference to left hemisphere involvement. DESIGN: Case studies of 3 patients with crossed aphasia, including language testing, computed tomographic scanning, and functional imaging with PET or SPECT. SETTING: Hospital case studies. PATIENTS: Three right-handed patients with crossed aphasia secondary to acute infarctions in the right hemisphere and left hemiparesis. METHODS: All 3 patients were studied by means of bedside language testing, computed tomographic scanning, and functional brain imaging with PET or SPECT. Patient 1 also underwent serial testing with the Boston Diagnostic Aphasia Examination and follow-up PET scanning after 2 months of recovery. OUTCOME MEASURES: Clinical examination in all 3 patients and follow-up Boston Diagnostic Aphasia Examination and PET scanning in patient 1. RESULTS: Two patients had severe global aphasia and 1 had Broca aphasia. In all cases, computed tomographic scans failed to reveal any left hemispheric lesions. Functional imaging with PET or SPECT showed extensive hypometabolism or hypoperfusion in the right hemisphere, with initial reductions in the left hemisphere as well. In patient I, a follow-up PET image showed only persistent hypometabolism in the right hemisphere. CONCLUSIONS: These findings suggest that abnormal dominance for at least some language functions in the right hemisphere underlies the syndrome of crossed aphasia. Diaschisis, or functional depression of the anatomically normal left hemisphere, was seen in all 3 patients during the acute phase, but not in patient 1 after recovery had begun.

Aged↗

PubMed1978