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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P300 event-related potentials to counted (target) and uncounted (background) visual stimuli were recorded from subjects who had sustained either a right or a left middle cerebral artery cerebrovascular accident (CVA) and from appropriate normal control subjects. Subjects were asked to count target stimuli and to ignore non-target stimuli. Standard measurements of the amplitude and latency of P300 components as well as intercorrelations among P300 wave forms from 3 brain regions (Fz, Cz, Pz) were collected. Amplitudes of N1-P2 and N2-P3 components as well as overall amplitude of the ERP wave form were reliably reduced by a CVA, but component latencies were not significantly affected. The amplitude reduction associated with a CVA cannot be simply interpreted as evidence for reduced cognitive efficiency because overall amplitudes and intercorrelations between brain regions of CVA patients were reduced for both counted and uncounted stimuli. The intercorrelations between brain regions were particularly reduced if the CVA was localized in the right hemisphere. For CVA patients, reduced component amplitudes may reflect decreased cortical intercommunication associated with damage to subcortical brain structures.
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PMID:Cerebrovascular accident alters P300 event-related potential characteristics. 241 13

In this double-blind, randomized study the efficacy of the ergoloid compounds, co-dergocrine mesylate and nicergoline, in the rehabilitation of patients with ischaemic stroke was investigated. A group of 30 patients was treated daily with 60 mg nicergoline, orally, and a second group of 27 patients was given 1.8-6 mg co-dergocrine mesylate, orally or intramuscularly, daily (depending on the time since the initial ischaemic insult) for 6 months. Outcome measures included: motoricity index (limb function); Sandoz Clinical Assessment Geriatric (SCAG) scale; psychometric tests to assess functions such as attention, psychomotor performance, perception and sensory and short-term memory; conventional and computerized electroencephalography; and P300 and reaction time measures. The results showed improvements in some aspects such as limb function (P < 0.05), SCAG score (P < 0.01) and some electrophysiological parameters (P < 0.01) after treatment with both drugs. Though statistically significant most of the changes were not large. The efficacy of both drugs was qualitatively similar. The quantitative difference in some aspects in favour of nicergoline could be attributed to differences in the mechanisms of action of the two drugs, although it is also possible that the difference may reflect the dosages used. Nootropic drugs may induce a condition that facilitates the effects of cognitive training.
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PMID:Ergoloids and ischaemic strokes; efficacy and mechanism of action. 764 39

Global and specific cognitive functions were assessed in 57 patients with ischemic strokes subjected to clinical neuropsychiatric, psychometric, electrophysiological and cranial tomographic evaluation. Patients did significantly worse than normal controls in the Blessed dementia scale, Sandoz clinical assessment geriatric scale but not the Folstein mini-mental state examination. Of the specific cognitive functions, attention and psychomotor performance were significantly impaired in stroke patients when compared to normal controls. The impairment in global cognitive functions, attention and psychomotor performance was more evident in chronic than acute cases. Increasing age correlated positively to the deterioration in psychomotor performance and perception. Cranial tomographic size of infarction was significantly related to global cognitive as well as intentional (sensory) memory impairment. The more marked the conventional electroencephalographic abnormalities, the more impaired were the global cognitive functions. High limit of the theta percent power correlated positively to deterioration in psychomotor performance. All P300 parameters except amplitude correlated significantly with impairment of global cognitive function and psychomotor performance in stroke patients.
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PMID:Cognitive deficits in ischemic strokes: psychometric, electrophysiological and cranial tomographic assessment. 780 62

A study was performed to compare the follow-up results of superficial temporal artery-middle cerebral artery anastomosis between a group of nine elderly patients (aged 70 years or over) and another group of 24 non-elderly patients (aged less than 70 years) with cerebral ischemia. The 33 patients, comprising 26 males and seven females, were evaluated pre- and postoperatively by four-vessel angiography, CT scan, MRI and cerebral blood flow (CBF) examination using either xenon inhalation or 123I-IMP SPECT. In some patients, additional evaluations were done. For those with dementia, the minimental scale (MMS), P300 event-related potential, the Hachinski ischemia score, and the vowel word counting test (Kaneko's KANAHIROI) were used, and for the hemiplegic, the Barthel index indicating ability of daily life (ADL) was employed. The results of follow-up for periods ranging from 12 to 55 months were "excellent" (returned to previous job) or "good" (able to perform self-care) in 27 of the 33 patients (81.8%) including six (66.6%) of the elderly group and 21 (87.5%) of the non-elderly group. There was no significant difference between the two groups by statistical evaluation. Among the nine patients with dementia (five under 70, four 70 years of age or over), eight (four under 70, four 70 or over) showed "rapid recovery" with improved postoperative MMS, P300, vowel word counting score and CBF. One patient under 70 (Case 5; a 47-year-old male) with a delayed 2-day recovery from general anesthesia, took as long as 6 months to obtain the self-care ability in daily life. Excluding this patient, all of the remaining eight patients responded quickly to surgery and were able to go home with their families after 2 to 4 weeks, there being no significant difference between the two age groups. In the 14 patients with hemiplegia/paresis (nine under 70, five 70 or over), a definitely better result was obtained for the non-elderly group. Eight of the nine non-elderly patients (89%) showed full ADL (Barthel index 100), whereas only one of three elderly patients (33.3%) showed almost full ADL (Barthel index 97). In five progressive stroke patients, (three under 70, two 70 or over) ultra-early bypass was performed within 8 hours postictus. Definitely better results were obtained in the patients aged less than 70, who showed rapid recovery and were able to return to their previous jobs 1 to 3 months after surgery. In contrast, the two patients aged 70 or over showed no improvement. In this report, we discuss the clinical and physiological variables that may be important for selection of elderly patients for cerebrovascular bypass surgery.
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PMID:[Results of superficial temporal artery-middle cerebral artery anastomosis for elderly and non-elderly patients with cerebral ischemia]. 782 13

The time course of neurophysiological parameters (EEG, evoked potentials of various modalities, including P300, and polysomnography) was followed up in 10 patients with apallic syndrome (AS) of nontraumatic origin (heart arrest, stroke, neuroinfection, etc.) during the formation of the syndrome and the condition of various severity: incomplete formation of AS eventuating in gross psychoneurological defects and complete formation of AS (a stable vegetative state). A dynamic follow-up of not only EEG of awaken and sleeping patients, but of their evoked potentials, specifically somatosensory and P300, were shown to be significant for assessment of the course of AS and prediction of its outcome.
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PMID:[Prognostic significance of neurophysiological parameters in nontraumatic apallic syndrome]. 875 66

We investigated possible correlations among neurophysiological examinations [auditory and visual event-related potentials (A-ERPs, V-ERPs), and flash visual evoked potentials (F-VEPs)] and neuropsychological tests [Mini-Mental State Examination (MMSE) and Raven's Coloured Progressive Matrices (RCPM)] in 15 subjects with probable or possible Alzheimer's disease (AD) according to the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria. The P300 latency of A-ERPs was correlated with the scores of MMSE but not with those of RCPM. The P300 latency of V-ERPs was more significantly correlated with the scores of RCPM than with those of MMSE. The P2 latency of F-VEPs was more significantly correlated with the scores of RCPM than with those of MMSE. The P2 latency of F-VEPs was not correlated with the P300 latency of A-ERPs but was correlated with the P300 latency of V-ERPs. The close relationship among V-ERPs, F-VEPs and RCPM suggests that these examinations at least partly reflect the functions of visual association areas in AD. Furthermore, discrepancy between P300 latency by A-ERPs and V-ERPs suggests that the mechanism responsible for P300 generation is not identical between these two stimulus modalities.
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PMID:Auditory and visual event-related potentials and flash visual evoked potentials in Alzheimer's disease: correlations with Mini-Mental State Examination and Raven's Coloured Progressive Matrices. 955 92

For many years people have speculated that electroencephalographic activity or other electrophysiological measures of brain function might provide a new non-muscular channel for sending messages and commands to the external world - a brain-computer interface (BCI). Over the past 15 years, productive BCI research programs have arisen. Encouraged by new understanding of brain function, by the advent of powerful low-cost computer equipment, and by growing recognition of the needs and potentials of people with disabilities, these programs concentrate on developing new augmentative communication and control technology for those with severe neuromuscular disorders, such as amyotrophic lateral sclerosis, brainstem stroke, and spinal cord injury. The immediate goal is to provide these users, who may be completely paralyzed, or 'locked in', with basic communication capabilities so that they can express their wishes to caregivers or even operate word processing programs or neuroprostheses. Present-day BCIs determine the intent of the user from a variety of different electrophysiological signals. These signals include slow cortical potentials, P300 potentials, and mu or beta rhythms recorded from the scalp, and cortical neuronal activity recorded by implanted electrodes. They are translated in real-time into commands that operate a computer display or other device. Successful operation requires that the user encode commands in these signals and that the BCI derive the commands from the signals. Thus, the user and the BCI system need to adapt to each other both initially and continually so as to ensure stable performance. Current BCIs have maximum information transfer rates up to 10-25bits/min. This limited capacity can be valuable for people whose severe disabilities prevent them from using conventional augmentative communication methods. At the same time, many possible applications of BCI technology, such as neuroprosthesis control, may require higher information transfer rates. Future progress will depend on: recognition that BCI research and development is an interdisciplinary problem, involving neurobiology, psychology, engineering, mathematics, and computer science; identification of those signals, whether evoked potentials, spontaneous rhythms, or neuronal firing rates, that users are best able to control independent of activity in conventional motor output pathways; development of training methods for helping users to gain and maintain that control; delineation of the best algorithms for translating these signals into device commands; attention to the identification and elimination of artifacts such as electromyographic and electro-oculographic activity; adoption of precise and objective procedures for evaluating BCI performance; recognition of the need for long-term as well as short-term assessment of BCI performance; identification of appropriate BCI applications and appropriate matching of applications and users; and attention to factors that affect user acceptance of augmentative technology, including ease of use, cosmesis, and provision of those communication and control capacities that are most important to the user. Development of BCI technology will also benefit from greater emphasis on peer-reviewed research publications and avoidance of the hyperbolic and often misleading media attention that tends to generate unrealistic expectations in the public and skepticism in other researchers. With adequate recognition and effective engagement of all these issues, BCI systems could eventually provide an important new communication and control option for those with motor disabilities and might also give those without disabilities a supplementary control channel or a control channel useful in special circumstances.
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PMID:Brain-computer interfaces for communication and control. 1204 38

The latency of the P300 and the simple reaction time (RT) generated by visual stimuli were investigated in a group of 43 healthy normals and in 24 stroke patients. The stroke patients were in a chronic phase of their disease. Twelve patients were without cognitive deficit, while 12 showed the symptoms of dementia. In the normals, P300 and RT showed a positive correlation with age. In comparing 12 age-matched normals with stroke patients with and without dementia, a similar latency of the P300 was found in the normals (347 msec) and in the stroke patients without dementia (349 msec). The patients with cognitive impairment showed a significant increase in their latency (434 msec). The RT was significantly different in the normals (421 msec) and stroke patients without dementia (533 msec) as well as in the stroke patients with dementia (663 msec). A significant correlation between the P300 and the RT was found.
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PMID:The value of P300 in the diagnosis of cognitive impairment in stroke. 1537 16

Seventeen right-handed patients suffering from global aphasia caused by a recent stroke in the left-hemisphere were studied. Passive P300 auditory event related potential paradigm was applied every months for 6 months. Aachen subtests were used for evaluating comprehension. Only a minority of the patients displayed the P300 at the baseline. Those patients had the best outcome at the Aachen comprehension subtest. Latency and amplitude changed over time in an unpredictable way. The number of patients presenting with the P300 also fluctuated, since some patients could regain the potential, whereas some other patients could lose that from month to month. Passive P300 is a monitor of recovery following global aphasia. A single passive P300 recording is useful for prognostic purposes. Repairing mechanisms in the first 6 months have a non-linear trend.
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PMID:The role of P300 in the recovery of post-stroke global aphasia. 1664 16

Although hypertension and alcohol dependence have been linked by epidemiological surveys and clinical observations, their interactive effects on brain function have rarely been tested. The present study involved the recording of P300 event related potentials (ERP) from 106 middle-aged African-American adults assigned to one of four groups: normotensive/nondependent (n=56), hypertensive/nondependent (n=11), normotensive/dependent (n=27), and hypertensive/dependent (n=12). The numbers of Nicotine Dependence, Major Depressive Disorder, and Conduct Disorder symptoms were specified as covariates within a 2 by 2 factorial design. ERPs were recorded during separate visual and auditory oddball tasks. The major result was a synergistic effect of hypertension and alcohol dependence on auditory P300 latency: the combination of both factors was associated with greater slowing than the sum of their independent effects. Future studies should continue to examine the potential synergistic effects of alcohol dependence and hypertension with a view toward identifying and reducing neurophysiological decrements and stroke risk among middle-aged patients.
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PMID:Interactive effects of hypertension and alcohol dependence on the P300 event-related potential in African-Americans. 1692 6


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