Mitochondrial DNA mutations in patients with postlingual, nonsyndromic hearing impairment.
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Mitochondrial mutations have previously been reported anecdotally in families with maternally inherited, nonsyndromic hearing impairment. To ascertain the contribution of mitochondrial mutations to postlingual but early-onset, nonsyndromic hearing impairment, we screened patients collected from within two different populations (southern Italy and UK) for previously reported mtDNA mutations associated with hearing disorders. Primer extension (SNP analysis) was used to screen for specific mutations, revealing cases of heteroplasmy and its extent. The most frequently implicated tRNA genes, Leu(UUR) and Ser(UCN), were also sequenced in all Italian patients. All tRNA genes were sequenced in those UK patients showing the clearest likelihood of maternal inheritance. Causative mtDNA mutations were found in approximately 5% of patients in both populations, representing almost 10% of cases that were clearly familial. Age of onset, where known, was generally before adulthood, and hearing loss was typically progressive. Haplogroup analysis revealed a possible excess of haplogroup cluster HV in the patients, compared with population controls, but of borderline statistical significance. In contrast, we did not find any of the previously reported mtDNA mutations, nor a significant deviation from haplogroup cluster frequencies typical of the control population, in patients with late adult-onset hearing loss (age-related hearing impairment) from the UK or Finland. (+info)
The effects of ageing and Alzheimer's disease on semantic and gender priming.
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Normal ageing as well as age-associated pathological conditions, such as Alzheimer's disease, are associated with modifications of language processing. In particular, an impaired performance in semantic tasks, associated with relatively spared syntactic processing, has been suggested to be the hallmark of the language disorder of Alzheimer's disease. The present experiment tests semantic and syntactic aspects of language processing at the same time, using an on-line paradigm, in patients with Alzheimer's disease, compared with elderly and young controls. Normal ageing was associated with a profile of performance, which was slowed but qualitatively comparable with that of young controls. Both gender agreement and congruent sentential semantics resulted in facilitation relative to baseline in young and elderly controls, with no significant interference effects of incongruent grammatical and semantic information. In contrast, Alzheimer's disease patients presented both facilitation and interference effects. These findings suggest that interference effects are amplified by dementia, and may result from defective inhibitory processes due to Alzheimer's disease pathology. (+info)
Validation of a Developmental Neuropsychological Assessment (NEPSY) through comparison of neurological, scholastic concerns, and control groups.
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Validity of the standard, 13 subtest A Developmental Neuropsychological Assessment (NEPSY) was investigated by comparing scores for 30 children with neurological conditions, 35 children with scholastic concerns, and 39 controls. Overall differences were found among the groups with and without controlling for IQ (Lambda = .60, Lambda = .001; Lambda = .70, P < .001). Four of five NEPSY domain scores differed among the three groups. Language and Sensorimotor domain score differences were found even when IQ was controlled, and group status accounted for substantial variance in these domain scores. Regarding specific tasks, Phonological Processing and Fingertip Tapping were among the subtests that varied the most between groups, especially when children with scholastic concerns were compared with controls. Findings offer preliminary support for the validity of several NEPSY indexes. (+info)
Cognitive rehabilitation for schizophrenia: is it possible? Is it necessary?
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Limitations of available psychosocial interventions combined with the increasing evidence that schizophrenia is characterized by diverse deficits in information processing has stimulated great interest in the possibility of cognitive rehabilitation. However, the current optimism seems unjustified. The precise role of information processing in the behavioral handicaps evidenced by schizophrenic patients is not clear, and the neuropsychologic and experimental psychopathology tasks used to assess information processing generally cannot specify precisely which cognitive functions are deficient. Thus, the choice of cognitive targets for rehabilitation is arbitrary. The strategies currently employed for rehabilitation emphasize an exercise model of treatment and the use of complex mnemonics. Neither approach has been successful in rehabilitating brain-injured patients, and preliminary results with schizophrenic patients are not very promising. It is concluded that the field might be better served by focusing on environmental change and compensatory strategies until we determine how and why schizophrenic patients fail. (+info)
Greater syntactic impairments in native language in bilingual Parkinsonian patients.
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OBJECTIVE: To investigate the presence of syntactic impairments in native language in Parkinson's disease. METHODS: Twelve bilingual patients, with Friulian as their first language (L1) and Italian as their second (L2), with Parkinson's disease and 12 normal controls matched for age, sex, and years of schooling, were studied on three syntactic tasks. RESULTS: Patients with Parkinson's disease showed a greater impairment of L1 than L2. CONCLUSIONS: These findings provide evidence of greater basal ganglia involvement in the acquisition and further processing of grammar in L1 v L2 possibly due to a major involvement of procedural memory in representing L1 grammar. (+info)
Early clinical differentiation of cerebral infarction from severe atherosclerotic stenosis and cardioembolism.
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BACKGROUND AND PURPOSE: Hyperacute cerebral infarction trials require early differentiation of infarction subtype. Our aim was to determine clinical factors predictive of infarction subtype from data collected in the early hours of admission. METHODS: Using the 1,273 patients enrolled in the Stroke Data Bank, stroke risk factors and demographic, clinical, and radiological features were compared between the 246 cardioembolic and 113 large-vessel atherosclerotic cerebral infarcts. RESULTS: Stroke Data Bank definitions ensured more transient ischemic attacks in atherosclerotic infarcts and more cardiac disease in cardioembolic infarcts, but the diagnosis was distinguished further using a logistic regression model. Fractional arm weakness (shoulder different from hand) (odds ratio 3.1, 95% confidence interval [CI] 1.6-5.8), hypertension (odds ratio 2.8, CI 1.4-5.3), diabetes (odds ratio 2.5, CI 1.2-5.1) and male gender (odds ratio = 2.2, CI 1.2-4.1) occurred more frequently in patients with atherosclerotic than cardioembolic infarcts. Reduced consciousness (odds ratio = 3.2, CI 1.4-7.3) was more frequent in cardioembolism. For a male patient with hypertension, diabetes, and fractional arm weakness, the estimated odds of an atherosclerotic infarction were 47-fold that of a cardioembolic infarction. Patients with atherosclerotic infarcts were more likely to have a fractional arm weakness regardless of infarct size, whereas, for those with cardioembolic infarctions, fractional weakness was more frequent in infarcts less than 20 cc in volume. CONCLUSIONS: Clinical features that are observed at stroke onset can help distinguish cerebral infarction subtypes and may allow for early stratification in therapeutic trials. (+info)
The effect of age and structural lesions on postictal language impairment.
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The duration of postictal language dysfunction following a temporal lobe complex partial seizure (TLCPS) is longer when the seizure originates in the dominant hemisphere. However, the effects of older age and the presence of a structural lesion ipsilateral to the area of origin of the seizure remain unknown. Postictal language delay (PILD) was analyzed in relation to age and presence of a structural lesion in 47 patients, 28 with dominant TLCPSs and 19 with nondominant TLCPSs (total 173 seizures). Mean ages of the groups were 32.5 years (range: 16-68) and 36.1 years (range: 21-50), respectively. Nonsclerotic structural lesions were found by magnetic resonance imaging in 13 patients, eight with seizures in the dominant hemisphere and five with seizures in the nondominant hemisphere. Age did not affect PILD regardless of the lateralization of the seizures. The presence of a structural lesion significantly prolonged PILD only in the patients with nondominant TLCPS (p = 0.019). In conclusion, the anatomical site of seizure onset may not be the only determinant of the nature of the postictal state. PILD can provide important information on seizure localization and spread. (+info)
New insights into the anatomo-functional connectivity of the semantic system: a study using cortico-subcortical electrostimulations.
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Despite a better understanding of the organization of the cortical network underlying the semantic system, very few data are currently available regarding its anatomo-functional connectivity. Here, we report on a series of 17 patients operated on under local anaesthesia for a cerebral low-grade glioma located within the dominant hemisphere. Prior to and during resection, intraoperative electrical stimulation was used to map sensorimotor and language structures so that permanent neurological deficits could be avoided. In a number of cases, cortical and subcortical stimulation caused semantic paraphasias. Using postoperative MRI, we correlated these functional findings with the anatomical locations of the sites where semantic errors were elicited by stimulation, especially at the subcortical level, with the aim of studying the connectivity underlying the semantic system. In temporal gliomas, cortical sites involved in semantic processing were found around the posterior part of the superior temporal sulcus, with subcortical pathways reproducibly located under the depth of this sulcus. In insular gliomas, although stimulation elicited no semantic disturbances at the cortical level, such semantic paraphasias were generated at the level of the anterior floor of the external capsule. In frontal tumours, cortical regions implicated in semantics were detected in the lateral orbitofrontal region and dorsolateral prefrontal cortex, with subcortical fibres located under the inferior frontal sulcus. All these eloquent structures were systematically preserved, thereby avoiding permanent postoperative deficits. Our results provide arguments in favour of the existence of a main ventral subcortical pathway underlying the semantic system, within the dominant hemisphere, joining the two essential cortical epicentres of this network: the posterior and superior temporal areas, and the orbitofrontal and dorsolateral prefontal regions. Such a ventral stream might anatomically partly correspond to the inferior fronto-occipital fasciculus. (+info)