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

The results from a topographic analysis of the early median nerve SEPs allowed to design a method for recording and analysing the SEPs in the routine laboratory. The detailed analysis of the topography of 50 normal subjects revealed: 1. An inter- and intraindividual variability of the location of the maximal amplitudes, 2. A significantly longer latency of the cortical potentials after left side stimulation, 3. A significantly higher amplitude of N20 after left side stimulation and 4. A significantly higher amplitude of the later potentials P25 and N30 after right side stimulation. It was shown that a 4-channel recording from the neck at C7 with a Fz-reference as well as from stimulus contralateral F3, CP3 and P3 or F4, CP4 and P4 with an stimulus contralateral earlobe reference provides all necessary parameters in comparison to an 20-channel recording. The definition of normal values has to take into account these results. Absolute maximum values were taken instead of the standard deviation because all amplitude values were proven to be not distributed normally. In 7 out of 30 MCA-stroke patients pathological SEP amplitudes were obtained using the 4-channel montage, whereas the 1-channel recording from CP3 and CP4 with a Fz-reference revealed normal amplitudes.
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PMID:[Topography of early cortical median nerve somatosensory evoked potentials: results for routine use of the method]. 148 25

Somatosensory potentials evoked by stimulation of the posterior tibial nerve (tibial nerve SEPs) were studied in 40 patients with supratentorial non-haemorrhagic cerebral infarction and in 25 control subjects, SEPs were recorded twice in 39 patients and thrice in 35 patients. The first examination was carried out 4-19 days after the onset of the symptoms, the second examination 56-100 days after the stroke, and the third examination 348-393 days after the stroke. Increased side-to-side differences in the P57 and N75 peak latencies and absence of the P40 peak were the most frequent abnormal findings. The latency abnormalities were associated with involvement of the subcortical white matter of the rolandic region. The absence of the P40 peak was, in contrast, closely related to the extension of the infarcted area into the cortical gray matter of the rolandic region. When all SEP abnormalities were taken into account 55% of patients showed at least one abnormality in the tibial nerve SEP during the acute stage, 51% of patients had abnormal SEPs in the second examination and 43% of patients in the third examination. A nearly significant decrease was observed in the number of latency abnormalities, but the number of amplitude abnormalities, including absent responses, did not change during the 1 year follow-up period.
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PMID:A prospective 1 year follow-up study with somatosensory potentials evoked by stimulation of the posterior tibial nerve in patients with supratentorial cerebral infarction. 171 36

Several authors have demonstrated a correlation between short latency somatosensory evoked potentials (short latency SEPs) and cerebral blood flow (CBF). It is also known that ischemia may modify the amplitude of the cortical SEP while its latency is less sensitive to CBF fluctuations. Phychotropic drugs--Oxiracetam, SAMe, Naloxone, L-acetylcarnitine and GM1--affect some parameters of the early components of cortical SEPs, chiefly the amplitude, which makes SEP recording a useful method for monitoring pharmacological activity in acute stroke.
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PMID:Effects of psychotropic drugs on somatosensory evoked potentials in cerebral ischemia. 187 7

We elicited motor evoked potentials (MEPs) using transcortical magnetic stimulation in 150 control subjects aged 14 to 85 years and 275 patients with a variety of diseases. There were no significant side effects. Cortex-to-target muscle latencies measured 20.2 +/- 1.6 ms (thenar), 14.2 +/- 1.7 ms (extensor digitorum communis), 9.4 +/- 1.7 ms (biceps), and 27.2 +/- 2.9 ms (tibialis anterior). Central motor delay between the cortex and the C-7 and L-5 measured 6.7 +/- 1.2 ms and 13.1 +/- 3.8 ms, respectively. Mean spinal cord motor conduction velocity measured 65.4 m/s. MEP amplitude expressed as a percentage of the maximum M wave was never less than 20% of the M wave. A value of less than 10% is considered abnormal. MEP latency increases linearly with age and central motor delay is longer in older subjects. Compound muscle action potentials and absolute MEP amplitudes decreased linearly with age. In multiple sclerosis (MS), MEP latency and central delay were often very prolonged. The MEP was more sensitive than the SEP in MS. In amyotrophic lateral sclerosis, MEP latencies were only modestly prolonged; the characteristic abnormality was reduced amplitude. When pseudobulbar features predominated MEPs were often absent. The MEP was of normal latency in Parkinson's disease, but age-related amplitude was often increased. MEP latency and amplitude were normal in Huntington's disease. Abnormal MEPs persisted several months after stroke despite good functional recovery. The MEP could be used to advantage to demonstrate proximal conduction slowing and block in demyelinating neuropathies. In plexopathy, ability to elicit an MEP several days after onset of paresis was good evidence of neuronal continuity in motor fibers.
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PMID:AAEM minimonograph #35: Clinical experience with transcranial magnetic stimulation. 793 34

A chronic canine model of hyperdynamic sepsis was achieved by cecal ligation and puncture (SEP) in conjunction with continuous high-volume fluid resuscitation. Cardiac function was evaluated using ultrasonic cardiac crystals placed across the major, minor, and wall thickness axes of the left ventricle, together with simultaneous arterial and ventricular pressure measurement. Seven to 10 days after crystal implantation, animals were randomized to either SEP (n = 10) or sham laparotomy control (n = 7). SEP dogs became febrile and lethargic, with elevated leukocyte counts and positive blood cultures for enteric organisms. They were also hyperdynamic, with significant increases in heart rate and cardiac output and a fall in systemic vascular resistance. Systolic blood pressure, stroke volume, and ejection fraction remained stable. Relative to control, the SEP group demonstrated a significant reduction in intrinsic contractility during systole, as measured by the heart rate and load-independent index of left ventricular performance Emax (P less than 0.01), confirming the observations of others. In addition, however, diastolic function also became markedly abnormal with a progressive increase in unstressed and end-diastolic ventricular volumes (P less than 0.05) and a significant decrease in myocardial compliance as quantitated by transmural pressure vs. volume-strain analysis. It is hypothesized that this increase in diastolic volume helps to maintain global cardiac performance during the hyperdynamic response to sepsis in the presence of adequate volume support.
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PMID:Sepsis-induced diastolic dysfunction in chronic canine peritonitis. 231 77

A typical case of mitochondrial encephalomyopathy with lactic acidemia and stroke-like episodes (MELAS) was reported. The main clinical manifestations consisted of short stature, psychomotor deterioration, sensorineural deafness, and hemiparesis. The laboratory findings disclosed abnormal lactic acid tolerance abnormal EEG, VEP, AEP, SEP, and MCV. The CT scan showed multiple intracerebral infarcts, basal ganglia calcifications, and cerebral atrophy. A muscle biopsy was performed. The frozen sections with modified gomori trichrome stain revealed ragged-red-fiber which reacted strongly positive in NADH-TR stain. The electron microscopy revealed subsarcolemmal aggregation of mitochondria of various sizes with paracrystalline inclusions, abnormally arranged cristae, and osmiophilic dense-bodies in their matrices.
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PMID:[Mitochondrial encephalomyopathy. Report of a case]. 234 80

SEPs may be recorded over the spine and scalp to stimulation of any accessible mixed or sensory nerve in the extremities. SEP abnormalities are useful in detecting lesions in central somatosensory pathways. They do not establish a specific diagnosis, but they may suggest or support a diagnosis made on clinical grounds. They have been used particularly to detect subclinical lesions in multiple sclerosis, but their role in following the course of this disorder is unclear. SEPs have been used as a prognostic guide in patients with hemispheric stroke and in patients who are comatose following head injury or severe cerebral anoxia; in such instances, however, the SEP often adds little to what can be determined by clinical examination. Their role in the evaluation of patients with brain death is controversial. Preserved SEPs or their early return after a spinal injury suggests an incomplete lesion, and therefore a better prognosis than otherwise. SEPs have been used to minimize or prevent intraoperative neurologic complications by monitoring spinal cord function, but their role in this regard awaits adequate validation. In patients with cervical spondylosis, SEPs elicited by stimulation of a nerve in the lower extremities may be helpful in indicating which patients are liable to develop a significant cord deficit, so that surgical treatment can be considered at an early stage. SEP abnormalities have been described in a number of other neurologic contexts, but the findings may be of more academic than clinical relevance in that they help to define the extent of neuropathologic involvement without altering the management of individual patients.
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PMID:The use of somatosensory evoked potentials in the evaluation of the central nervous system. 307 Mar 40

Short latency SEP were investigated in 140 patients suffering from various cerebrovascular ischemic disease (CVD). CCT,AR and number of cortical phases of each stimulation side, as well as AR left to right side (AR l/r) were correlated to patient's age and sex, to diagnosis and vascular supply, to clinical symptoms, duration between stroke and investigation, SPECT, TCT and EEG. Significant correlations were found between CCT and diagnosis, vascular supply, clinical symptoms, duration, SPECT and TCT findings. CCT was prolonged in patients with completed stroke, MID, ischemia of the A.C.M., sensomotor hemiparesis or monoparesis of the upper extremity and lesions in SPECT and TCT located within thalamus and/or postcentral gyrus. Decreased perfusion in SPECT was only of statistical significance when it was combined with clinical symptoms and/or lesions in TCT. Significant correlations were found between AR l/r and all variables except age and sex. Differences in sub-groups corresponded to those found for the CCT. AR was lower at the affected side. Deviations of AR were also found in patients with focal lesions both in the EEG and in the TCT. Significant correlations were found between number of phases, clinical findings and SPECT, but no correlation was seen to TCT. Patients with CVD showed significant abnormalities of CCT and AR only in cases presenting neurological deficit and structural lesion in TCT. The abnormalities were more prominent in patients with an interval stroke-investigation over one year. No abnormalities were seen in patients with reversible symptomatology investigated after cessation of symptoms. A direct correlation may be suspected between number of phases and tracer uptake in SPECT.
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PMID:[Early somatosensory evoked potentials in cerebrovascular ischemic diseases. III. Correlations with age, sex, clinical data, EEG, emission and transmission computed tomography]. 313 95

We believe that somatosensory and brainstem auditory evoked response studies help in the understanding of the dysfunction of the ascending sensory pathyways at various levels. In some patients where EEGs showed a significant contamination of muscle and background noise, the SEP studies helped to identify the level of dysfunction. The severity of the clinical condition (GCS score) correlated significantly (p = 0.003) with the prolongation of the CCT. Asymmetries in CCTs were more frequent in the stroke group than in the other groups. The presence of asymmetries in CCT in diffuse encephalopathies indicated a variable degree of dysfunction in the ascending sensory pathways, which clinically were not easily identifiable. This fact raised the possibility of either pre-existing lesion(s) or recent insult(s) such as ischemia. The presence or absence of N20 appeared to influence the duration of survival in subgroups. Some degree of difference in duration of survival was noted among the metabolic group with and without N20 potential. The subset of patients with N20 potential survived relatively longer than the group without it. A suggestion of influence was seen in the stroke group, but caution must be exercised because the absence of N20 was compatible with survival. The hypoxic group did not show any difference. A combination of prolonged interpeak EP-N13 and N13-N20 indicated a poor prognosis. A distinct absence of Wave I in BAER limited its usefulness on some occasions. A combination of abnormal interpeak III-V and abnormal CCT seemed to suggest a poor prognosis. Although death generally occurred earlier in the stroke group, age did not seem to influence the mortality in the first 10 days. Similarly, the cause of death also did not seem to influence the course in those 10 days. None of the adult patients survived.
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PMID:Somatosensory and brainstem auditory evoked potential studies in nontraumatic coma. 339 8

Noninvasive electrophysiological evaluation with sensory evoked potentials would be of clear diagnostic and prognostic value in evaluating comatose patients with stroke or severe head injury. In order to protect the brain from such kinds of insults, barbiturate coma therapy has been employed and its effectiveness has been already established. However, in the barbiturate coma therapy, it is occasionally difficult to distinguish the pharmacological effect of barbiturate from the preexisting brain dysfunction caused by the underlying process of the disease. In adult cats, authors studied changes of sensory evoked potentials following cumulative intravenous administration of thiopental which is used clinically for barbiturate coma therapy. P1 and N1 of cortical SEP showed tendency of gradual decrease in amplitude. However, no significant changes occurred in latency by stepwise increment of thiopental dose. Changes in amplitude of P1 and N1 of cortical SEP preceded to the flattening on electroencephalogram. Around at the level of the concentration where EEG changes began, I-II interpeak latency of BAEP and latency of wave I of short latency SEP started to increase. BAEP and early components of SEP (I.II.III.IV) persisted even in by far the higher level of serum concentration of thiopental than that of clinical use. Furthermore, most of these parameters showed no statistically significant change neither in amplitude nor in latency. These experimental results suggest that sensory evoked potentials will provide us with useful information in the assessment of the brainstem function in patients under thiopental induced deep coma.
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PMID:[Effects of thiopental on sensory evoked potentials in the cat]. 373 Jan 99


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