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Biomedical subjects

R P Brenner

Publications and source records attributed to R P Brenner.

At least 37 records · Page 2Linked to original sources
PubMed1990

Myoclonic status epilepticus: a clinical and electroencephalographic study.

We reviewed the clinical features and ictal EEGs in 23 adults with myoclonic status epilepticus (MSE). Anoxic encephalopathy was the most common cause of MSE, occurring in 15 patients; 8 developed MSE within 14 hours following the anoxic insult. Metabolic encephalopathies were present in 4 patients, while 2 had degenerative CNS disorders. In 2 patients with generalized epilepsy, MSE developed during a medication change. Five types of EEG patterns were associated with MSE. Generalized periodic complexes (usually spikes, polyspikes, or sharp waves), often with attenuation of background activity between complexes (11 patients) or a burst-suppression pattern (4 patients), were the most common types. Outcome was poor: 20 patients died without regaining consciousness, while 1 remains in a vegetative state. The 2 patients with generalized epilepsy, both of whom were conscious during MSE, survived without sequelae.

Adult↗
PubMed1990

Periodic EEG patterns: classification, clinical correlation, and pathophysiology.

In this article, we review periodic EEG patterns, which have been classified into four different types based on their interval duration (short or long) and topographic distribution (lateralized, bilaterally independent, or diffuse and synchronous). The four patterns are: (1) periodic lateralized epileptiform discharges; (2) bilateral independent periodic lateralized epileptiform discharges; (3) periodic short-interval diffuse discharges; and (4) periodic long-interval diffuse discharges. We also discuss morphology, etiologies, and clinical correlates of each pattern and possible pathophysiological mechanisms of periodicity.

Brain Diseases↗
PubMed1989

EEG findings in depressive pseudodementia and dementia with secondary depression.

We report EEG findings in 33 elderly patients with mixed symptoms of depression and dementia, followed longitudinally to confirm diagnosis. Two groups of patients, dementia with depressive features (mixed-DEM, group I, n = 23) and patients with depressive pseudodementia (mixed-DEP, group II, n = 10), were defined. In addition, we also included, for comparison purposes, 35 patients with probable AD without depressive features (group III), 23 patients with major depression without cognitive impairment (group IV), and 61 healthy elderly controls (group V). We found significant group differences on waking EEGs between those mixed patients who did well after treatment for depression (depressive pseudodementia) compared to patients having dementia with secondary depression. The differences paralleled those between the 'pure' groups of demented and depressed patients. In patients with either depression or depressive pseudodementia, the EEG was usually normal or showed only mild abnormalities. In contrast, the majority of patients with either dementia or dementia with secondary depression had abnormal EEGs, with approximately one-third having moderate (or severe) abnormalities. Although the EEG was usually normal or only mildly abnormal in patients with pseudodementia or depression, these groups (II and IV) did show a significant slowing of the dominant posterior rhythm compared to controls. They also had a higher percentage of generalized abnormal EEGs than controls and this difference was significant between group IV (depression) and controls.

Aged↗
PubMed1989

Seizures after liver transplantation: a clinicopathologic study.

We reviewed the clinical and neuropathologic findings in 21 patients who had seizures after orthotopic liver transplants. Tonic-clonic seizures were the most common seizure type. Six patients developed status epilepticus. In 9 patients, seizures occurred within 1 week following transplantation. We found CNS lesions that were probably responsible for the occurrence of seizures in most patients; some had more than 1 finding. Neuropathologic examination revealed ischemic or hemorrhagic strokes in 18 patients, central pontine myelinolysis in 5, and CNS infections in 5. Multiple metabolic abnormalities were a contributing factor to the onset of seizures in some patients.

Adult↗
PubMed1988

Topographic maps of brain electrical activity--pitfalls and precautions.

Topographic mapping of brain electrical activity is a popular, powerful, and potentially misleading technique. The map lies at the end of a long chain of physiological, technical, electronic, and mathematical processes and is vulnerable to artifact, error, and distortion at many points. Close attention must be paid to data collection parameters, subject cooperation, minimization of artifact, limitations of resolutions, selection, and transformation of parameters for display, and map generation strategy to yield an accurate, physiologically interpretable map. Review of the data at each step of analysis, from the paper electroencephalogram (EEG) to sets of maps on video display, may be necessary for optimum understanding. Development of more sophisticated qualitative and quantitative concepts of "normal" physiology is needed. These improvements in electrophysiological data analysis demand, rather than obviate, sophistication on the part of the user.

Arousal↗
PubMed1988

Electroencephalographic correlates of increased platelet membrane fluidity in Alzheimer's disease.

Increased platelet membrane fluidity is a stable, familial characteristic that describes a clinically distinct subgroup of patients with Alzheimer's disease. In the current study, electroencephalograms (EEGs) from 49 patients with probable Alzheimer's disease were subjected to visual and computerized spectral analysis. Only three (14.3%) of 21 patients in the subgroup with increased platelet membrane fluidity exhibited focal EEG abnormalities, while 12 (42.9%) of 28 of the residual subgroup exhibited focal EEG findings, a threefold difference. This difference in EEG profile provides further validation of these two subgroups and suggests that the subgroup with increased fluidity is less heterogeneous than the residual group.

Alzheimer Disease↗
PubMed1988

Delirium in liver transplantation candidates: discriminant analysis of multiple test variables.

We report the results of electroencephalograms, Mini-Mental State exam, Trailmaking Tests A and B, and serum albumin levels in 108 consecutive liver transplantation candidates. We compared test results to a clinical DSM-III diagnosis of delirium. Although each variable could differentiate between the two groups (delirium n = 18; nondelirium n = 90) at a statistically significant level, a discriminant analysis involving either all variables or only three particular variables (Trailmaking B, EEG code, and albumin) resulted in the highest specificity (97.8%) and sensitivity (83.3%), with a correct classification of 95.4% of subjects. The analysis also generates an equation that can be applied to clinical situations to enhance the accurate recognition of delirium. In addition, to explain abnormal Trailmaking B scores and/or EEGs in subjects who did not otherwise meet DSM-III criteria for delirium, we suggest the presence of a "subclinical delirium."

Adolescent↗
PubMed1988

Changes in EEG mean frequency associated with anxiety and with amphetamine challenge in BPD.

Recent authors have hypothesized that cerebral dysfunction, as reflected in an abnormal EEG, may play an important role in the behavioral symptoms of patients with borderline personality disorder (BPD). Spectral analysis and amphetamine challenge testing are two promising methods for probing the clinical symptomatology of this disorder. In this study, we evaluated the relationship between clinical symptoms and computerized EEG spectral analysis in BPD patients both before and after amphetamine challenge. We found that mean frequency values on spectral analysis consistently correlated with anxiety levels in our patients, but did not correlate with a wide variety of other important symptoms, such as depression or transient psychosis. This result, coupled with our previous negative findings concerning EEG abnormalities in patients with BPD, casts doubt on the etiological relationship of cerebral dysrhythmias to the behavioral pathology of this disorder, but raises interesting questions concerning the relationship of anxiety and mean frequency.

Adult↗
PubMed1988

Diagnostic efficacy of computerized spectral versus visual EEG analysis in elderly normal, demented and depressed subjects.

Computerized spectral and visual EEG analyses were performed in 35 patients with Alzheimer's disease (AD) and compared to 23 patients with major depression and to 61 healthy elderly controls. In particular, we were interested in the diagnostic efficacy of these two techniques in the identification of cases of AD with only mild cognitive impairment (as measured by the Folstein Mini-Mental State score). For the computer analyzed data, in differentiating AD patients from controls, the spectral pooled parasagittal mean frequency was used. In comparing AD patients to depressed subjects, a combined parasagittal delta and theta spectral score was employed. Visual analysis criteria were based on the severity of generalized EEG abnormalities (with or without focal features). We found that spectral analysis afforded only modest advantages over visual EEG analysis in differentiating AD patients from elderly controls as well as from those with major depression. Since the degree of spectral and visual EEG abnormalities correlated with the severity of dementia, both tests more often correctly classified those AD patients with lower Folstein scores. Also, both tests identified primarily the same patients. We did not find the computer to be more sensitive than the eye in the identification of AD patients with mild impairment. However, computerized spectral data was derived from only 4 channels, while 16 channels and a longer recording time were used for visual analysis. In addition, some areas which have been reported to show EEG abnormalities in AD were not included in the computerized data.

Aged↗
PubMed1987

Myoclonic seizures with lithium.

Myoclonus has been infrequently observed in patients receiving lithium therapy, and associated electroencephalographic (EEG) changes have not been well described. We report two women, ages 35 and 48, who, after the initiation of lithium carbonate therapy, had several generalized tonic-clonic seizures followed by myoclonic seizures. In both, myoclonus was associated with repetitive sharp waves on the EEG. Although the epileptogenicity of lithium remains controversial, the occurrence of myoclonic seizures associated with lithium treatment suggests a proconvulsant effect of lithium in susceptible individuals.

Adult↗
PubMed1987

Brainstem death with persistent EEG activity: evaluation by xenon-enhanced computed tomography.

A patient with brainstem infarction met the clinical criteria for brain death but had persistent EEG activity, complicating our decision to withdraw life support. We evaluated cerebral blood flow with xenon-enhanced computed tomography (Xe/CT), which documented the absence of posterior circulation flow and persistent, low, anterior circulation flow. This information led us to withdraw life support, despite the presence of EEG activity. The Xe/CT method noninvasively measures local cerebral blood flow and may enhance diagnostic certainty in complicated brain-death evaluations.

Brain Death↗
PubMed1986

Computerized EEG spectral analysis in elderly normal, demented and depressed subjects.

Computerized spectral analysis of the EEG was performed in 35 patients with Alzheimer's disease and compared to patients with major depression (23) and healthy elderly controls (61). Compared to controls, demented patients had a significant increase in the theta and alpha 1 bandwidths as well as an increased theta-beta difference. The parasagittal mean frequency, beta 1 and beta 2 activity were significantly decreased. Depressed patients differed from demented patients, particularly at the lower end of the spectrum, having significantly less delta and theta activity. Like the demented group, depressed patients also had a decreased parasagittal mean frequency, beta 1 and beta 2 when compared to controls. In demented patients, there was a high correlation between several spectral parameters (parasagittal mean frequency, delta and theta activity, and the theta-beta difference) and the Folstein score, EEG measures used for discriminant analysis were more accurate in identifying demented patients who had lower Folstein scores.

Aged↗
PubMed1985

The electroencephalogram in altered states of consciousness.

The EEG can be very helpful in the evaluation of patients with altered states of consciousness. Diffuse slowing of background rhythms and the presence of triphasic waves suggests metabolic dysfunction, particularly hepatic. Generalized fast activity may be seen in patients with a drug intoxication. Abnormalities, such as PLEDs or focal continual PDA, support a diagnosis of supratentorial lesion, whereas a normal appearing EEG in a comatose patient suggests a brain-stem lesion. In addition, the EEG may reveal that the alteration in consciousness is due to continual epileptic activity without motor manifestations (nonconvulsive status) that had not been suspected. As indicated, certain patterns have prognostic implications. However, as these patterns are not specific for a single etiology, the EEG is of most help when the cause is known. For example, burst suppression or a diffuse alpha pattern coma can be seen in either hypoxia or a drug intoxication. With hypoxia, these patterns carry an extremely poor prognosis for useful recovery, whereas complete recovery is often seen in cases secondary to drug ingestion. As a more extreme example, a patient whose EEG shows ECS secondary to drug intoxication may recover but will not if the ECS is due to hypoxia or severe head trauma. If the etiology of the encephalopathy is unknown, then sequential records are needed for prognosis.

Adolescent↗
PubMed1984

Multiple Sleep Latency Test findings in Kleine-Levin syndrome.

Multiple Sleep Latency Test (MSLT) findings in a case of Kleine-Levin syndrome are reported for the first time. MSLT data indicate sleepiness as severe as in narcolepsy or obstructive sleep apnea and the occurrence of four sleep onset rapid eye movement (REM) periods, with a greater REM propensity at 2:00 p.m. and 4:00 p.m. than at 10:00 a.m. and 12:00 noon. The replication of such findings might suggest that Kleine-Levin syndrome could be considered a form of periodic REM sleep disinhibition. Therefore, the traditional hypothesis of diencephalic dysfunction may require modification to include the role of more caudal brain stem structures specifically activated during REM sleep.

Adult↗
PubMed1983

Midline spikes. EEG and clinical features.

Clinical features of 40 patients with midline spikes on EEG were compared with those of age- and sex-matched controls. Seizure incidence was significantly greater in the study group than in the controls (85% v 45%). Tonic-clonic seizures were the most frequent type. Eighteen patients from the study group had additional focal or generalized epileptiform abnormalities. This subgroup had a significantly greater incidence of seizures than patients with only midline spikes (100% v 73%). Midline spikes are more common in children and markedly activated with sleep. They must be distinguished from normal sleep transients.

Adolescent↗
PubMed1982

Generalized paroxysmal fast activity: electroencephalographic and clinical features.

We reviewed electroencephalographic and clinical features of 20 patients with generalized paroxysmal fast activity (GPFA). All had seizure disorders and all but 3 had more than one seizure type. Mental retardation was present in 17 patients. In most cases no cause for the seizures could be found. GPFA occurred almost exclusively in sleep. Fifteen patients had clinical seizures associated with this activity; in 8 the seizures were tonic. Additional generalized epileptiform abnormalities were present in 18 patients, 10 of whom had slow spike and wave complexes. Only 4 patients had normal background activity.

Adolescent↗