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V M Synek

Publications and source records attributed to V M Synek.

10 recordsLinked to original sources
PubMed1991

Important abnormalities in recordings of somatosensory evoked potentials in coma.

We have chosen six illustrations showing how much vital information can be obtained from median nerve SEPs during the first 24 hours in coma. With avulsion of brachial plexus roots there was loss of SEPs at the cervical cord and the scalp from the affected side. In a severe injury of the cervical cord there was preservation of brachial plexus potentials, while SEPs at the cervical cord were absent. After critical deterioration in a case of repeated subarachnoidal hemorrhage, scalp SEPs with very short latency occurred, which is a finding suggestive of destruction of cortical SEP generators heralding a fatal outcome. In a case of brain injury combined with central hyperthermia, there was initially a loss of scalp SEPs probably due to the combined effect of these factors. In a case of brain injury there were bifid peaks at the scalp level. It is important to assess central sensory conduction time only to the first scalp SEP, otherwise an erroneously abnormal state may be inferred. In a patient with clinical and EEG evidence of brain death there was a loss of far-field thalamic potentials at the neck. It is important to be aware of such presentations to be able to provide corroborative assurance for the assessment of prognosis.

Adult↗
PubMed1991

Re: EEG in coma.

Explore the source record for details and available documents.

Coma↗
PubMed1990

Value of a revised EEG coma scale for prognosis after cerebral anoxia and diffuse head injury.

The prognostic validity for survival of a recently devised EEG grading scale was tested in anoxic and post-traumatic coma. This scale divides EEG in coma into five major grades and ten subdivisions with emphasis on the presence of dominant activities, their amplitude, persistence, distribution and reactivity. In this scale, patterns previously not allocated, such as "spindle pattern coma," "alpha pattern coma," and "theta pattern coma" are also included. The prognostic power of the revised scale was tested retrospectively without knowledge of clinical data in a group of patients with cerebral anoxia after cardiac arrest lasting more than seven minutes and in a group of diffuse head injuries. The validity of the scale was found to be higher than those used in previously published studies, reaching 98.4% prognostic accuracy in anoxic encephalopathies and was very high in head injuries.

Coma↗
PubMed1990

Revised EEG coma scale in diffuse acute head injuries in adults.

The validity of a recently published EEG grading scale applied to patients with acute head injuries has been investigated. This scale is based on 15 individual grades and subdivisions and 3 major groups: 4 patterns are benign regarding survival, 4 are of uncertain significance and 7 patterns are prognostically malignant. The evaluation was performed in 90 adult patients with acute head injuries in whom EEGs obtained during the 36 hours after the injury were evaluated retrospectively without knowing the clinical details or the outcome. By employing previously reported definitions it was possible to allocate EEG abnormalities in all cases. The assumption was made that at the time of the EEG investigation the impact of the head injury on cerebral function was already established. All patients displaying 'benign' patterns survived. 'Uncertain' patterns were the most common ones and in patients with these the reactivity of EEG activity was more important for prognosis than the quality of the background activity. All but 3 of the patients with a 'malignant' pattern died, and the survivors remained in a vegetative state. There was a correlation between the EEG findings and the Glasgow Coma Scale score on admission and also with the results of computerized tomography of the brain. In those patients who died there was no significant relationship between EEG signs and autopsy findings. Repeated EEGs are always desirable with severe head injuries but the results of this study suggest that useful prognostic information can be obtained from an EEG recorded within 36 hours after the head trauma.

Adolescent↗
PubMed1989

Epileptiform discharges in presence of continuous background activity in anoxic coma.

The EEGs of a group of patients in anoxic coma following cardiorespiratory arrest were retrospectively studied. Twelve of 70 patients had at least one EEG recorded during the acute period which consisted of epileptiform discharges in the presence of continuous diffuse background activity. Nine of the patients died while three made a generally favorable recovery. The analysis confirms the prediction of a recent revision of EEG grades in coma that this particular pattern of activity is of uncertain prognostic significance. This is in contrast to the occurrence of epileptiform discharges during discontinuous "burst suppression" activity which generally indicates a fatal outcome.

Aged↗
PubMed1989

Validity of a revised EEG coma scale for predicting survival in anoxic encephalopathy.

A revised EEG grading scale in coma has been introduced previously. This scale is based on the internationally accepted 5 grade scale but also contains uncommon patterns such as spindle, alpha and theta pattern comas. By defining 15 separate grades and subgrades it was possible to reduce the number of patterns of uncertain prognostic significance for survival to 4 out of the 15 possible patterns. It is also hoped that by a clear definition of individual grades and subdivisions the scale will assist electroencephalographers who lack experience of coma cases. The validity of the scale has been tested in a group of 63 patients who suffered cardiac arrest in excess of 7 minutes' duration. The EEG was performed 24 to 36 hours after the onset of coma. The accuracy of prediction for survival was 98.4%, a rate higher than in previously published studies. The mortality rate was 70%, 19 patients surviving. There was a statistically significant correlation between mortality rate and duration of cardiac arrest and also between mortality rate and increasing age. Four suggested scale subdivisions did not occur in the material studied but these subdivisions are more common in traumatic encephalopathies. This study shows that an EEG performed 24 to 36 hours after cardiac arrest provides significant information for the prediction of survival. No specific patterns of microscopic changes in the brain were found to correlate with individual EEG abnormalities in fatal anoxic encephalopathies.

Adult↗
PubMed1987

Intersession stability of somatosensory evoked potentials.

Upper and lower limb nerve somatosensory evoked potentials (SEPs) were recorded from a group of normal adults in order to assess their intersession stability. Median, peroneal and sural nerve SEPs were recorded from each subject on 3 successive occasions at weekly intervals. For median nerve SEPs, the intrinsic variability was more pronounced for interpeak latencies (N9-N20, N13-N20) than for the latencies of individual components. Their inherent fluctuation was not, however, notably greater for the primary cortical response (N20) than for the more caudally generated components (N9 and N13). These relationships were not so apparent for lower limb SEPs where intersession variability was markedly greater overall than for upper limb SEPs.

Adolescent↗
PubMed1986

Validity of median nerve somatosensory evoked potentials in the diagnosis of supraclavicular brachial plexus lesions.

Experience with median nerve SEPs in the diagnosis of brachial plexus lesions is analysed in 49 patients selected from a total material of 264 cases with brachial plexus problems tested by SEP techniques. Median nerve SEPs were always compared with the results of SEPs after stimulation of at least one other nerve relevant to the site of the lesion as suspected clinically and electromyographically. All patients presented with unilateral brachial plexus problems and all root lesions were verified by clinical presentation, EMG studies, myelogram or surgery. There were 19 brachial plexus injuries, 13 cases with cervical spondylopathic radiculopaties without myelopathy and 7 patients presented brachial plexopathy with systemic cancer. It was found that median nerve SEPs were always normal in injuries of upper trunk and root avulsions confined to one or two root levels. Median nerve SEPs were abnormal in multiple trunk lesions and multiple root avulsions. In patients with spondylopathic radiculopathies median nerve SEPs were normal apart from one case where involvement of multiple roots was present. Median nerve SEPs were useful in assessing patients presenting brachial plexus problems in the presence of systematic cancer apart from cases where lower trunk involvement was present. In general, median nerve SEPs are useful if they are combined with SEP testing of other nerves anatomically more closely related to the problem as outlined clinically and electromyographically.

Adolescent↗
PubMed1985

Recovery from alpha coma after decompression sickness complicated by spinal cord lesions at cervical and midthoracic levels.

A modified alpha pattern activity occurred in the EEG of a 21-year-old man during recovery from a diving injury. It persisted for 10 days but finally the EEG became normal. There was clinical and neurophysiological evidence of additional separate lesions in the cervical and mid-thoracic spinal cord. The latter resulted in spastic paraplegia but the patient made an otherwise good recovery.

Adult↗