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Leadership Through Friendship: The Dangers and Advantages of State Leaders Establishing Close Personal Relations
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What does a cue do? Comparing phonological and semantic cues for picture naming in aphasia
Purpose: Impaired naming is one of the most common symptoms in aphasia, often treated with cued picture naming paradigms. It has been argued that semantic cues facilitate the reliable categorisation of the picture, and phonological cues facilitate the retrieval of target phonology. To test these hypotheses, we compared the effectiveness of phonological and semantic cues in picture naming for a group of individuals with aphasia. To establish the locus of effective cueing, we also tested whether cue type interacted with lexical and image properties of the targets.
Method: Individuals with aphasia (n=10) were tested with a within-subject design. They named a large set of items (n=175) four times. Each presentation of the items was accompanied by a different cueing condition (phonological, semantic, non-associated word and tone). Item level variables for the targets (i.e., phoneme length, frequency, imageability, name agreement and visual complexity) were used to test the interaction of cue type and item variables. Naming accuracy data was analysed using generalised linear mixed effects models.
Results: Phonological cues were more effective than semantic cues, improving accuracy across individuals. However, phonological cues did not interact with phonological or lexical aspects of the picture names (e.g., phoneme length, frequency). Instead, they interacted with properties of the picture itself (i.e., visual complexity), such that phonological cues improved naming accuracy for items with low visual complexity.
Conclusions: The findings challenge the theoretical assumptions that phonological cues map to phonological processes. Instead, phonological information benefits the earliest stages of picture recognition, aiding the initial categorization of the target. The data help to explain why patterns of cueing are not consistent in aphasia, i.e., it is not the case that phonological impairments always benefit from phonological cues and semantic impairments form semantic cues. A substantial amount of the literature in naming therapy focuses on picture naming paradigms. Therefore, the results are also critically important for rehabilitation, allowing for therapy development to be more rooted in the true mechanisms through which cues are processed
Residual cognitive deficits 50 years after lead poisoning during childhood
The long term neurobehavioural consequences of childhood lead poisoning are not known. In this study adult subjects with a documented history of lead poisoning before age 4 and matched controls were examined with an abbreviated battery of neuropsychological tests including measures of attention, reasoning, memory, motor speed, and current mood. The subjects exposed to lead were inferior to controls on almost all of the cognitive tasks. This pattern of widespread deficits resembles that found in children evaluated at the time of acute exposure to lead rather than the more circumscribed pattern typically seen in adults exposed to lead. Despite having completed as many years of schooling as controls, the subjects exposed to lead were lower in lifetime occupational status. Within the exposed group, performance on the neuropsychological battery and occupational status were related, consistent with the presumed impact of limitations in neuropsychological functioning on everyday life. The results suggest that many subjects exposed to lead suffered acute encephalopathy in childhood which resolved into a chronic subclinical encephalopathy with associated cognitive dysfunction still evident in adulthood. These findings lend support to efforts to limit exposure to lead in childhood
Visual processing speed is linked to functional connectivity between right frontoparietal and visual networks
Visual information processing requires an efficient visual attention system. The neural theory of visual attention (TVA) proposes that visual processing speed depends on the coordinated activity between frontoparietal and occipital brain areas. Previous research has shown that the coordinated activity between (i.e., functional connectivity and âinter-FCâ) cingulo-opercular (COn) and right-frontoparietal (RFPn) networks is linked to visual processing speed. However, how inter-FC of COn and RFPn with visual networks links to visual processing speed has not been directly addressed yet. Forty-eight healthy adult participants (27 females) underwent resting-state (rs-)fMRI and performed a whole-report psychophysical task. To obtain inter-FC, we analyzed the entire frequency range available in our rs-fMRI data (i.e., 0.01â0.4 Hz) to avoid discarding neural information. Following previous approaches, we analyzed the data across frequency bins (Hz): Slow-5 (0.01â0.027), Slow-4 (0.027â0.073), Slow-3 (0.073â0.198), and Slow-2 (0.198â0.4). We used the mathematical TVA framework to estimate an individual, latent-level visual processing speed parameter. We found that visual processing speed was negatively associated with inter-FC between RFPn and visual networks in Slow-5 and Slow-2, with no corresponding significant association for inter-FC between COn and visual networks. These results provide the first empirical evidence that links inter-FC between RFPn and visual networks with the visual processing speed parameter. These findings suggest that direct connectivity between occipital and right frontoparietal, but not frontoinsular, regions support visual processing speed
Functional outcome is tied to dynamic brain states after mild to moderate traumatic brain injury
The current study set out to investigate the dynamic functional connectome in relation to long-term recovery after mild to moderate traumatic brain injury (TBI). Longitudinal resting-state functional MRI data were collected (at 1 and 3âmonths postinjury) from a prospectively enrolled cohort consisting of 68 patients with TBI (92% mild TBI) and 20 healthy subjects. Patients underwent a neuropsychological assessment at 3âmonths postinjury. Outcome was measured using the Glasgow Outcome Scale Extended (GOS-E) at 6âmonths postinjury. The 57 patients who completed the GOS-E were classified as recovered completely (GOS-E = 8; n = 37) or incompletely (GOS-Eâ<â8; n = 20). Neuropsychological test scores were similar for all groups. Patients with incomplete recovery spent less time in a segregated brain state compared to recovered patients during the second visit. Also, these patients moved less frequently from one meta-state to another as compared to healthy controls and recovered patients. Furthermore, incomplete recovery was associated with disruptions in cyclic state transition patterns, called attractors, during both visits. This study demonstrates that poor long-term functional recovery is associated with alterations in dynamics between brain networks, which becomes more marked as a function of time. These results could be related to psychological processes rather than injury-effects, which is an interesting area for further work. Another natural progression of the current study is to examine whether these dynamic measures can be used to monitor treatment effects
Divergent effects of healthy ageing on semantic knowledge and control:Evidence from novel comparisons with semantically-impaired patients
Grey and white matter correlates of recent and remote autobiographical memory retrieval:Insights from the dementias
The capacity to remember self-referential past events relies on the integrity of a distributed neural network. Controversy exists, however, regarding the involvement of specific brain structures for the retrieval of recently experienced versus more distant events. Here, we explored how characteristic patterns of atrophy in neurodegenerative disorders differentially disrupt remote versus recent autobiographical memory. Eleven behavioural-variant frontotemporal dementia, 10 semantic dementia, 15 Alzheimer's disease patients and 14 healthy older Controls completed the Autobiographical Interview. All patient groups displayed significant remote memory impairments relative to Controls. Similarly, recent period retrieval was significantly compromised in behavioural-variant frontotemporal dementia and Alzheimer's disease, yet semantic dementia patients scored in line with Controls. Voxel-based morphometry and diffusion tensor imaging analyses, for all participants combined, were conducted to investigate grey and white matter correlates of remote and recent autobiographical memory retrieval. Neural correlates common to both recent and remote time periods were identified, including the hippocampus, medial prefrontal, and frontopolar cortices, and the forceps minor and left hippocampal portion of the cingulum bundle. Regions exclusively implicated in each time period were also identified. The integrity of the anterior temporal cortices was related to the retrieval of remote memories, whereas the posterior cingulate cortex emerged as a structure significantly associated with recent autobiographical memory retrieval. This study represents the first investigation of the grey and white matter correlates of remote and recent autobiographical memory retrieval in neurodegenerative disorders. Our findings demonstrate the importance of core brain structures, including the medial prefrontal cortex and hippocampus, irrespective of time period, and point towards the contribution of discrete regions in mediating successful retrieval of distant versus recently experienced events
Validity of the Clock Drawing Test in predicting reports of driving problems in the elderly
BACKGROUND: This study examined the use of the Folstein Mini Mental Status Exam (MMSE) and the Clock Drawing Test (CDT) in predicting retrospective reports of driving problems among the elderly. The utility of existing scoring systems for the CDT was also examined. METHODS: Archival chart records of 325 patients of a geriatric outpatient clinic were reviewed, of which 162 had CDT results (including original clock drawings). T-test, correlation, and regression procedures were used to analyze the data. RESULTS: Both CDT and MMSE scores were significantly worse among non-drivers than individuals who were currently or recently driving. Among current or recent drivers, scores on both instruments correlated significantly with the total number of reported accidents or near misses, although the magnitude of the respective correlations was small. Only MMSE scores, however, significantly predicted whether or not any accidents or near misses were reported at all. Neither MMSE nor CDT scores predicted unique variance in the regressions. CONCLUSIONS: The overall results suggest that both the MMSE and CDT have limited utility as potential indicators of driving problems in the elderly. The demonstrated predictive power for these instruments appears to be redundant, such that both appear to assess general cognitive function versus more specific abilities. Furthermore, the lack of robust prediction suggests that neither are sufficient to serve as stand-alone instruments on which to solely base decisions of driving capacity. Rather, individuals who evidence impairment should be provided a more thorough and comprehensive assessment than can be obtained through screening tools
Effects of Age of Onset of Tonic-Clonic Seizures on Neuropsychological Performance in Children
Forty-eight children (aged 9 to 15 years) with tonic-clonic seizures were administered a neuropsychological test battery. The children with seizures of early onset (before age 5) were significantly impaired relative to the children with later onset on 8 of the 14 measures in the battery. The deficits were seen on tasks whose requirements included the repetition of a simple motor act, attention and concentration, memory, and complex problem solving. These findings emphasize the need for further research to determine the causal factors of the greater dysfunction seen in the early onset group. RĂSUMĂ Quarante huit enfants ĂgĂs de 9 Ă 15 ans souffrant de crises Ăpileptiques tonico-cloniques ont ĂtĂĂtudiĂs avec une batterie de tests neuropsychologiques. Pour huit des quatorze mesures de cette batterie de tests les enfants dont les cirses avaient dĂbutĂ prĂcocĂment (avant cinq ans) se sont avĂrĂs Ătre signiflcativement dĂtĂriorĂs par rapport Ă ceux dont les crises avaient dĂbutĂ plus tardivement. Les dĂficits se sont manifestĂs pour des tĂches nĂcessitant la rĂpĂtition d'un acte moteur simple, attention et concentration, mĂmoire et capacitĂĂ rĂsoudre des problĂmes complexes. Ces rĂsultats mettent l'accent sur la nĂcessitĂ de poursuivre les recherches afin de dĂterminer les facteurs responsables de la plus grande dysfonction observĂe chez les enfants dont l'Ăpilepsie a dĂbutĂ tĂt dans la vie. RESUMEN Se ha aplicado una bateria de tests neuro-psicolĂgicos a 48 niĂos de 9 a 15 aĂos de edad que padecĂan ataques tonico-clĂnicos. Los niĂos con ataques de comienzo precoz (antes de los 5 aĂos) mostraron incapacidades significativas compareĂndolos con niĂos con comienzos mĂs tardios en 8 de los 14 tests de la bateria. Los defectos fueron detectados en las pruebas cuyos requisitos incluĂan la repeticiĂn de un acto motor simple, atenciĂn y concentraciĂn, memoria y resoluciĂn de problemas complejos. Estos hallazgos indican la necesidad de continuar la inves-tigaciĂn para determinar los factores causales de la mayor disfunciĂn observada en el grupo de comienzo precoz. ZUSAMMENFASSUNG 48 Kinder (9 bis 15 Jahre alt) mit tonisch-klonischen KrĂmpfen wurden mit einer neuropsychologischen Testbatterie untersucht. Die Kinder mit einem FrĂhbeginn der AnfĂlle (vor dem Alter von 5 Jahren) zeigten sich bei 8 von 14 Tests der Serie deutlich beeintrĂchtigt im VerhĂltnis zu Kindern mit spĂterem Anfallsbeginn. Die Defekte traten bei Aufgaben auf, die folgende AnsprĂche stellten: Wiederholung einer einfachen motorischen Handlung, Aufmerksamkeit und Konzentration, GedĂchtnis und komplexes ProblemlĂsen. Diese Befunde deuten auf die Notwendigkeit weiterer Untersuchungen, um die ursĂchlichen Faktoren der grĂĂeren FunktionseinbuĂe zu bestimmen, die bei Patienten mit frĂhem Anfallsbeginn beobachtet wird.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65238/1/j.1528-1157.1981.tb04102.x.pd
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