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Biomedical subjects

E Niedermeyer

Publications and source records attributed to E Niedermeyer.

At least 73 records · Page 4Linked to original sources
PubMed1984

Polysomnography of torsion dystonia.

Nocturnal EEG, electro-oculograms, and electromyograms were studied in nine patients with dystonia musculorum deformans and in nine healthy controls. Electrodes were placed over frontal, central, and occipital regions in accordance with the international 10-20 system of electrode placement. A standard bipolar montage was used for the recordings, and records were scored independently in accordance with the manual of Rechtschaffen and Kales. All patients were found to sleep poorly. Patients in advanced stages of dystonia all displayed an EEG pattern characterized by pronounced, high-amplitude (greater than 150 microV) spindles that were continuous for all stage 2 and portions of stage 3 sleep. Other sleep parameters were also disturbed. Sleep spindles become less frequent and diminish in amplitude with advancing age. The spindle activity of patients with advanced dystonia presents a stark contrast to this pattern and may underscore their clinical significance.

Adolescent↗
PubMed1984

Mechanisms by which epinephrine augments cerebral and myocardial perfusion during cardiopulmonary resuscitation in dogs.

The goals of this study were to quantify the effects of epinephrine on myocardial and cerebral blood flow during conventional cardiopulmonary resuscitation (CPR) and CPR with simultaneous chest compression-ventilation and to test the hypothesis that epinephrine would improve myocardial and cerebral blood flow by preventing collapse of intrathoracic arteries and by vasoconstricting other vascular beds, thereby increasing perfusion pressures. Cerebral and myocardial blood flow were measured by the radiolabeled microsphere technique, which we have previously validated during CPR. We studied the effect of epinephrine on established arterial collapse during CPR with simultaneous chest compression-ventilation with the abdomen bound or unbound. Epinephrine reversed arterial collapse, thereby eliminating the systolic gradient between aortic and carotid pressures and increasing cerebral perfusion pressure and cerebral blood flow while decreasing blood flow to other cephalic tissues. Epinephrine produced higher cerebral and myocardial perfusion pressures during CPR with simultaneous chest compression-ventilation when the abdomen was unbound rather than bound because abdominal binding increased intracranial and venous pressures. In other experiments we compared the effect of epinephrine on blood flow during 1 hr of either conventional CPR or with simultaneous chest compression-ventilation with the abdomen unbound. Epinephrine infusion during conventional CPR produced an average cerebral blood flow of 15 ml/min . 100 g (41 +/- 15% of control) and an average myocardial blood flow of 18 ml/min . 100 g (15 +/- 8% of control). In our previous studies, cerebral and myocardial blood flow were less than 3 +/- 1% of control during conventional CPR without epinephrine. Although flows during CPR with simultaneous chest compression-ventilation without epinephrine were initially higher than those during conventional CPR, arterial collapse developed after 20 min, limiting cerebral and myocardial blood flow. The use of epinephrine throughout 50 min of CPR with simultaneous chest compression-ventilation maintained cerebral blood flow at 22 +/- 2 ml/min . 100 g (73 +/- 25% control) and left ventricular blood flow at 38 +/- 9 ml/min . 100 g (28 +/- 8% control). The improved blood flows with epinephrine correlated with improved electroencephalographic activity and restoration of spontaneous circulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Electrocorticography: information derived from intraoperative recordings during seizure surgery.

The findings of 100 consecutive electrocorticographies in 94 epileptic patients were reviewed. Most of these patients underwent temporal lobectomies. A well defined and circumscript cortical spike focus was found in only 28 tracings whereas multiple sub-foci of spike activity or dissipated areas of spiking were demonstrated in 46 recordings. Cortical spike activity was minimal in 14 and absent in 12 tracings. Additional one-lead depth electrodes (inserted mainly into amygdala and hippocampus) yielded rather little information in contrast to the wealth of information derived from chronic multiple-leads depth implants prior to surgery. The frequent occurrence of dissipated spike foci suggests that, in partial epilepsies (and especially in temporal lobe epilepsy), epileptogenic zones are more widespread than one would expect from the scalp EEG recordings. These findings lend support to the use of en-bloc removal of large portions of an affected lobe.

Adolescent↗
PubMed1984

[Short sleep on the EEG--a source of otherwise overlooked EEG abnormalities].

A short sleep portion in an otherwise routinely performed EEG evaluation is often highly informative. This is particularly true for epileptological conditions. Several paroxysmal discharges are demonstrable solely in sleep and/or drowsiness; these potentials remain undetected in a waking tracing. Hence the inclusion of a sleep portion may be crucial in the assessment of epileptic seizure disorders but tends to yield less information in non-epileptic conditions. Sedation (Chloral Hydrate) is recommended if sleep does not occur spontaneously.

Adolescent↗
PubMed1984

Case report: polysomnographic effects of thalamotomy for torsion dystonia.

We report a patient with torsion dystonia whose polysomnographic recordings revealed poor sleep and a pronounced and almost continuous type of spindle activity during non-rapid eye movement sleep. Rapid eye movement sleep was also reduced. These changes proved to be independent of medications. After a clinically successful unilateral thalamic operation, a normalization of sleep parameters and a reduction of the high amplitude sleep spindles was observed, implying that the regulation of sleep spindles and the advancement of dystonic symptoms are affected by a common mechanism.

Adult↗
PubMed1983

Electrophysiological studies in Tourette's syndrome.

The value of standard electrophysiological studies using electroencephalography and evoked responses was evaluated in patients with Tourette's syndrome. Sixteen-channel electroencephalograms were obtained in 40 patients (36 males, 4 females) awake and asleep, and evoked responses were obtained in a subgroup of 17 patients. Evoked response variables evaluated included latencies and amplitudes of visual evoked responses, brainstem auditory evoked responses, and somatosensory evoked responses to median and peroneal nerve stimulation. Only 5 of the 40 patients (12.5%) demonstrated electroencephalographic abnormalities, which included central spikes, generalized and paroxysmal slow activity, and slowing of the normal basic frequency. Evoked response studies demonstrated no consistent differences between the patients with Tourette's syndrome and age- and sex-matched controls. The data demonstrate no notable diagnostic or therapeutic value for routine electroencephalographic or evoked response studies in Tourette's syndrome.

Adolescent↗
PubMed1983

Polysomnographic findings in dystonia musculorum deformans.

Twenty-five cases from the literature and four personal cases with dystonia musculorum deformans are described. The polysomnographic EEG findings of severely involved patients were characterized by over abundance of stage 2 sleep, with a characteristic pattern of spindle activity, increased latency to sleep, and reduced sleep efficiency. The similarities between these patients may underscore the importance of sleep spindles as a feature of the dystonia process and may be useful in the investigation of other basal ganglia disorders.

Adult↗
PubMed1983

Psychogenic seizures: a clinical study with follow-up data.

We evaluated the natural history and prognosis of psychogenic or hysterical seizures in patients discharged from the Johns Hopkins Hospital in the 3 years between 1971 and 1974. Follow-up data were obtained 5 years or more after discharge. Among 41 patients with convincing evidence of psychogenic seizures, there were coexisting organic neurologic disorders in 18 (44%). Mental subnormality or retardation was present in 17% and true epileptic seizures in 37%. EEG abnormalities found in 38% of individuals with psychogenic seizures were attributed to these organic neurologic disorders or anticonvulsant drug toxicity. There was significant long-term morbidity in 56% of these individuals because of psychosocial problems rather than misdiagnosis of psychogenic seizures.

Adolescent↗
PubMed1982

Sleep spindles recorded from deep cerebral structures in man.

The depth and scalp EEG findings in 73 patients with intractable epileptic seizure disorder and in 14 patients with intractable pain were reviewed; stress was laid on the area of earliest spindle activity. It was found that sleep spindles frequently occurred first in frontal depth leads and especially in the superior frontal region (supplementary motor region). In some cases, spindles in frontal depth leads occurred while the patient showed early drowsy activity or even waking activity (with posterior basic rhythm) in the scalp leads. In patients with thalamic implants, spindles tended to appear on the thalamus before appearance on the scalp. The general rule that sleep onset (NREM) is characterized by the appearance of spindles is valid for the scalp EEG only. Deep spindle activity occurs much earlier and probably requires a certain degree of synchronization before spindle activity is noticeable in scalp leads. The superior frontal region is likely to be the starting point of spindle activity.

Adult↗
PubMed1981

Subacute encephalopathy with seizures in alcoholics: a clinical-electroencephalographic study.

A subacute form of encephalopathy was observed in 7 patients with a history of severe chronic alcoholism. These episodes lasted about 1 to 6 weeks and were characterized by epileptic seizures (grand mal, focal motor), prominent EEG abnormalities with focal features (slowing, spiking, "PLEDs") and neurological deficits such as hemianopsia or hemiparesis. These changes resolved with symptomatic (mainly anticonvulsive) treatment but recurrences occurred in 3 cases. The clinical picture does not fit any of the known CNS complications of chronic alcoholism and there seems to be no relationship to alcohol withdrawal. Impressive EEG abnormalities strongly differ from the mild abnormalities or normal tracings found in other CNS complications of alcoholism. The pathogenetic mechanisms are essentially obscure; vascular changes might play a contributory role in some of the cases.

Adult↗
PubMed1981

Complexities of primary generalized epilepsy.

Abnormal arousal responses paired with paroxysmal discharges and photosensitivity are the principal mechanisms in the precipitation of seizures in primary generalized epilepsy. The abnormal arousal responses show a consistent maximum over the frontal midline region. An exception from this rule was found in two children with primary generalized epilepsy (petit mal absences, one also with grand mal) with a strongly positive family history. In these patients, the generalized-synchronous bursts showed a maximum over the vertex (Cz electrode). Both of these children also had single spikes over the Rolandic region. A relationship between primary generalized and benign Rolandic epilepsy is demonstrated. Both forms of seizure disorder are based on dysfunction (hyperexcitability) rather than on a structural epileptogenic lesion. A dichotomy of dysfunctional and structural epilepsies is presented but gray zones of overlap indubitably exist. The limitations of the dichotomy concept are pointed out.

Arousal↗
PubMed1979

Hypersomnia with simultaneous waking and sleep patterns in the electroencephalogram. A case report with neurotransmitter studies.

A mildly dyslexic boy of 11 years, with no neurological deficit or history of epileptic seizures, had marked hypersomnia for 2 years, which was most pronounced in the morning hours. Repeated EEG studies and power spectral analysis revealed simultaneous posterior alpha rhythm and sleep patterns (spindles, vertex waves, K complexes) over vertex and frontocentral regions, while the patient was behaviorally awake. Bilateral synchronous anterior spikes were frequently noted in association with sleep patterns. A polysomnogram over 24 h confirmed excessive sleep, night and day (especially morning hours) and there was evidence of a large REM sleep percentage (on EMG and EOG basis) while the EEG had predominantly non-REM sleep patterns. Special neurotransmitter studies were performed in view of a presumed disturbance affecting the neurobiochemical sleep regulation. These studies were based on CSF metabolite levels and provided evidence for a high serotonin metabolite (5HIAA) level. It is tempting to hypothesize that the biochemical disturbance has led to encroachment of non-REM sleep patterns on both wakefulness and REM sleep. Further discussion deals with the bilateral-synchronous spike activity and its relationship to arousal patterns in sleep.

Child↗
PubMed1979

Absence status (petit mal status) with focal characteristics.

Two patients, aged 23 and 74 years, manifested prolonged episodes of mildly impaired consciousness in conjunction with rhythmical spike waves or spikes (mostly 3/s). This paroxysmal EEG activity was consistently accentuated unilaterally over the superior frontal regions. The first patient showed ictal aphasia and occasional right hemiparesis during these episodes, and partial left frontal lobectomy resulted in temporary freedom from seizures. The classification of these ictal episodes is difficult. They apparently fall into the category of absence status (petit mal status), but the focal neurological signs do not fit the presently valid definitions of absence status, nor does the lack of symmetrical bilateral-synchronous paroxysmal discharges. Perhaps a special category of status epilepticus should be established.

Adolescent↗
PubMed1979

Myoclonus and the electroencephalogram, a review.

Myoclonus is a phenomenon which cuts through a considerable number of neurological conditions. It occurs in a variety of epileptic conditions (Primary generalized epilepsy, hypsarrhythmia, Lennox-Gastaut syndrome, also known as "petit mal variant"), in inborn errors of metabolism (Tay-Sachs disease, forms of ceroid lipofuscinosis), in neurobiochemically still poorly understood forms of degenerative processes such as Essential hereditary myoclonus epilepsy (Lafora-Unverricht-Lundborg), in benign heredo-degenerative disorders (Hartung's syndrome), in CNS infections (SSPE, Jakob-Creutzfeldt disease), in metabolic encephalopathies (renal failure, hypoglycemia), in CNS poisoning, in acute cerebral anoxia and in post-anoxic states. The EEG plays a crucial role in the differential diagnosis of these conditions by the demonstration of a) presence or absence of typical inter-ictal abnormalities, and b) various correlates of the myoclonic ictal event.

Adolescent↗
PubMed1979

Acute convulsions.

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Acute Disease↗
PubMed1978

Thalamic EEG recordings in patients with chronic pain.

Thalamic EEG recordings were made in 10 patients; the therapeutic goal of the implantation was the electrical stimulation treatment for pain. The patients' ages ranged from 37 to 72 years; seven patients had thalamic pain (Dejerine-Roussy syndrome), two had chronic spinal arachnoiditis and one had facial anaesthesia dolorosa. Platinum-iridium electrodes were stereotaxically inserted; the ventrobasal complex of the thalamus including the ventral posterior zone was the target of the implant. Excessive thalamic slowing was found in four of seven patients with Dejerine-Roussy syndrome and also in two of three cases with other causes of pain. One patient had marked rhythmical intermittent delta activity in the thalamus which was often triggered by arousing stimuli. Thalamic spindle activity was sometimes noted without concomitant spindle activity on the scalp and would occasionally occur in states of early drowsiness.

Adult↗