"Bottom-up" and "top-down" effects on reading saccades: a case study.
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OBJECTIVE: To investigate the role right foveal/parafoveal sparing plays in reading single words, word arrays, and eye movement patterns in a single case with an incongruous hemianopia. METHODS: The patient, a 48-year-old right handed male with a macular sparing hemianopia in his left eye and a macular splitting hemianopia in his right eye, performed various reading tasks. Single word reading speeds were monitored using a "voice-trigger" system. Eye movements were recorded while reading three passages of text, and PET data were gathered while the subject performed a variety of reading tasks in the camera. RESULTS: The patient was faster at reading single words and text with his left eye compared with his right. A small word length effect was present in his right eye but not his left. His eye movement patterns were more orderly when reading text with his left eye, making fewer saccades. The PET data provided evidence of "top-down" processes involved in reading. Binocular single word reading produced activity in the representation of foveal V1 bilaterally; however, text reading with the left eye only was associated with activation in left but not right parafoveal V1, despite there being visual stimuli in both visual fields. CONCLUSIONS: The presence of a word length effect (typically associated with pure alexia) can be caused by a macular splitting hemianopia. Right parafoveal vision is not critically involved in single word identification, but is when planning left to right reading saccades. The influence of top-down attentional processes during text reading can be visualised in parafoveal V1 using PET. (+info)
Defining a role for the subthalamic nucleus within operative theoretical models of subcortical participation in language.
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OBJECTIVE: To investigate the effects of bilateral, surgically induced functional inhibition of the subthalamic nucleus (STN) on general language, high level linguistic abilities, and semantic processing skills in a group of patients with Parkinson's disease. METHODS: Comprehensive linguistic profiles were obtained up to one month before and three months after bilateral implantation of electrodes in the STN during active deep brain stimulation (DBS) in five subjects with Parkinson's disease (mean age, 63.2 years). Equivalent linguistic profiles were generated over a three month period for a non-surgical control cohort of 16 subjects with Parkinson's disease (NSPD) (mean age, 64.4 years). Education and disease duration were similar in the two groups. Initial assessment and three month follow up performance profiles were compared within subjects by paired t tests. Reliability change indices (RCI), representing clinically significant alterations in performance over time, were calculated for each of the assessment scores achieved by the five STN-DBS cases and the 16 NSPD controls, relative to performance variability within a group of 16 non-neurologically impaired adults (mean age, 61.9 years). Proportions of reliable change were then compared between the STN-DBS and NSPD groups. RESULTS: Paired comparisons within the STN-DBS group showed prolonged postoperative semantic processing reaction times for a range of word types coded for meanings and meaning relatedness. Case by case analyses of reliable change across language assessments and groups revealed differences in proportions of change over time within the STN-DBS and NSPD groups in the domains of high level linguistics and semantic processing. Specifically, when compared with the NSPD group, the STN-DBS group showed a proportionally significant (p<0.05) reliable improvement in postoperative scores achieved on the word test-revised (TWT-R), as well as a reliable decline (p<0.01) in the accuracy of lexical decisions about words with many meanings and a high degree of relatedness between meanings. CONCLUSIONS: Bilateral STN-DBS affects certain aspects of linguistic functioning, supporting a potential role for the STN in the mediation of language processes. (+info)
Quality of life in multiple sclerosis: translation in French Canadian of the MSQoL-54.
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BACKGROUND: Multiple Sclerosis (MS) is a neurodegenerative disease which runs its course for the remainder of the patient's life frequently causing disability of varying degrees. Negative effects on Health-related quality of life (HRQOL) are well documented and a subject of clinical study. The Multiple Sclerosis QOL 54 (MSQOL-54) questionnaire was developed to measure HRQOL in patients with MS. It is composed of 54 items, and is a combination of the SF-36 and 18 disease-specific items. OBJECTIVE: The objective of this project was to translate the MSQOL-54 into French Canadian, and to make it available to the Canadian scientific community for clinical research and clinical practice. METHODS: Across all French speaking regions, there are occurrences of variation. They include the pronunciation, sentence structure, and the lexicon, where the differences are most marked. For this reason, it was decided to translate the US original MSQOL-54 into French Canadian instead of adapting the existing French version. The SF-36 has been previously validated and published in French Canadian, therefore the translation work was performed solely on the 18 MS specific items. The translation followed an internationally accepted methodology into 3 steps: forward translation, backward translation, and patients' cognitive debriefing. RESULTS: Instructions and Items 38, 43, 45 and 49 were the most debated. Problematic issues mainly resided in the field of semantics. Patients' testing (n = 5) did not reveal conceptual problems. The questionnaire was well accepted, with an average time for completion of 19 minutes. CONCLUSION: The French Canadian MSQOL-54 is now available to the Canadian scientific community and will be a useful tool for health-care providers to assess HRQOL of patients with MS as a routine part of clinical practice. The next step in the cultural adaptation of the MSQOL-54 in French Canadian will be the evaluation of its psychometric properties. (+info)
The role of syntactic complexity in treatment of sentence deficits in agrammatic aphasia: the complexity account of treatment efficacy (CATE).
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This experiment examined the hypothesis that training production of syntactically complex sentences results in generalization to less complex sentences that have processes in common with treated structures. Using a single subject experimental design, 4 individuals with agrammatic aphasia were trained to comprehend and produce filler-gap sentences with wh-movement, including, from least to most complex, object-extracted who-questions, object clefts, and sentences with object-relative clausal embedding. Two participants received treatment first on the least complex structure (who-questions), and 2 received treatment first on the most complex form (object-relative constructions), while untrained sentences and narrative language samples were tested for generalization. When generalization did not occur across structures, each was successively entered into treatment. Results showed no generalization across sentence types when who-questions were trained; however, as predicted, object-relative training resulted in robust generalization to both object clefts and who-questions. These findings support those derived from previous work, indicating not only that generalization occurs across structures that are linguistically related, but also that generalization is enhanced when the direction of treatment is from more complex to less complex constructions. This latter finding supports the authors' newly coined "complexity account of treatment efficacy" (CATE). (+info)
Verb deficits in Alzheimer's disease and agrammatism: implications for lexical organization.
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This study examined the nature of verb deficits in 14 individuals with probable Alzheimer's Disease (PrAD) and nine with agrammatic aphasia. Production was tested, controlling both semantic and syntactic features of verbs, using noun and verb naming, sentence completion, and narrative tasks. Noun and verb comprehension and a grammaticality judgment task also were administered. Results showed that while both PrAD and agrammatic subjects showed impaired verb naming, the syntactic features of verbs (i.e., argument structure) influenced agrammatic, but not Alzheimer's disease patients' verb production ability. That is, agrammatic patients showed progressively greater difficulty with verbs associated with more arguments, as has been shown in previous studies (e.g., Kim & Thompson, 2000; Thompson, 2003; Thompson, Lange, Schneider, & Shapiro, 1997), and suggest a syntactic basis for verb production deficits in agrammatism. Conversely, the semantic complexity of verbs affected PrAD, but not agrammatic, patients' performance, suggesting "bottom-up" breakdown in their verb lexicon, paralleling that of nouns, resulting from the degradation or loss of semantic features of verbs. (+info)
Agrammatic comprehension of simple active sentences with moved constituents: Hebrew OSV and OVS structures.
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This study examines agrammatic comprehension of object-subject-verb (OSV) and object-verb-subject (OVS) structures in Hebrew. These structures are syntactically identical to the basic order subject-verb-object (SVO) sentence except for the movement of the object to the beginning of the sentence, and thus enable empirical examination of syntactic movement in agrammatic comprehension. Seven individuals with agrammatism, 7 individuals with conduction aphasia, and 7 individuals without language impairment, all native speakers of Hebrew, performed a sentence-picture matching task. The task compared OSV and OVS sentences to SVO sentences and to subject and object relatives. Individuals with agrammatism performed more poorly than those in either of the other groups. Their comprehension of SVO sentences was significantly above chance, but comprehension of OSV and OVS sentences was at chance and was poorer than comprehension of SVO sentences. These results show that agrammatic comprehension of structures that involve movement of a noun phrase is impaired even when the structure is a simple active sentence, in line with the Trace Deletion Hypothesis (TDH; Y. Grodzinsky, 1990, 1995a, 2000). A modification is suggested to accommodate the TDH with the VP Internal Subject Hypothesis, according to which individuals with agrammatism use an "Avoid Movement" strategy in comprehension. (+info)
Visual command hallucinations in a patient with pure alexia.
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Around 25% of patients with visual hallucinations secondary to eye disease report hallucinations of text. The hallucinated text conveys little if any meaning, typically consisting of individual letters, words, or nonsense letter strings (orthographic hallucinations). A patient is described with textual visual hallucinations of a very different linguistic content following bilateral occipito-temporal infarcts. The hallucinations consisted of grammatically correct, meaningful written sentences or phrases, often in the second person and with a threatening and command-like nature (syntacto-semantic visual hallucinations). A detailed phenomenological interview and visual psychophysical testing were undertaken. The patient showed a classical ventral occipito-temporal syndrome with achromatopsia, prosopagnosia, and associative visual agnosia. Of particular significance was the presence of pure alexia. Illusions of colour induced by monochromatic gratings and a novel motion-direction illusion were also observed, both consistent with the residual capacities of the patient's spared visual cortex. The content of orthographic visual hallucinations matches the known specialisations of an area in the left posterior fusiform gyrus--the visual word form area (VWFA)--suggesting the two are related. The VWFA is unlikely to be responsible for the syntacto-semantic hallucinations described here as the patient had a pure alexic syndrome, a known consequence of VWFA lesions. Syntacto-semantic visual hallucinations may represent a separate category of textual hallucinations related to the cortical network implicated in the auditory hallucinations of schizophrenia. (+info)
Computational constraints on syntactic processing in a nonhuman primate.
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The capacity to generate a limitless range of meaningful expressions from a finite set of elements differentiates human language from other animal communication systems. Rule systems capable of generating an infinite set of outputs ("grammars") vary in generative power. The weakest possess only local organizational principles, with regularities limited to neighboring units. We used a familiarization/discrimination paradigm to demonstrate that monkeys can spontaneously master such grammars. However, human language entails more sophisticated grammars, incorporating hierarchical structure. Monkeys tested with the same methods, syllables, and sequence lengths were unable to master a grammar at this higher, "phrase structure grammar" level. (+info)