EEG monitoring of clinical coma

Karnaze, Dean S.; Marshall, Lawrence F.; Bickford, Reginald G.

doi:10.1212/wnl.32.3.289

Cited by 61 publications

(18 citation statements)

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“…showed that variability of EEG activity was the second most relevant finding leading to the identification of specific EEG patterns in DLB or PDDF (p<0.001) as reported in a previous study [83]. The variability of the EEG frequencies in relaxed waking conditions was best evidenced by using the CSA method of representation, showing that dominant frequencies (DF) in DLB were either in the pre-alpha band or varied across time with pseudocyclic patterns of delta-theta/pre-alpha or theta-pre-alpha/alpha, differentiating DLB or PDDF patients from AD or PDDNF patients.…”

Section: Neuroimaging For Clinicians -Combining Research and Practicesupporting

confidence: 78%

“…The variability of the EEG frequencies in relaxed waking conditions was best evidenced by using the CSA method of representation, showing that dominant frequencies (DF) in DLB were either in the pre-alpha band or varied across time with pseudocyclic patterns of delta-theta/pre-alpha or theta-pre-alpha/alpha, differentiating DLB or PDDF patients from AD or PDDNF patients. CSA representation had only been previously used to assess coma or anaesthesia levels [83], and in the present study it allowed to evidence changes of EEG activities in single derivations. It allowed therefore to evaluate local variability, at contrary with total QEEG analyses and MF evaluations, and to evidence that significant differences among groups of patients were prevalent in posterior leads.…”

Section: Quantitative Eeg:qeegmentioning

confidence: 98%

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Is There a Place for Clinical Neurophysiology Assessments in Synucleinopathies?

Onofrj¹,

Bonanni²,

Thomas³

et al. 2011

Neuroimaging for Clinicians - Combining Research and Practice

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IntroductionParkinson Disease (PD), Dementia with Lewy Bodies (DLB) and Multiple System Atrophy (MSA) are characterized by deposition of Lewy Bodies (LB), consisting of eosinophilic intracellular (intraneural in PD and DLB and intraglial in MSA) inclusions of -synuclein and allowing the three disorders to be categorized as synucleinopathies. The identification in the last two decades of specific clinical features of synucleinopathies has been a major breakthrough in Neurology, as it prompted a reconsideration of diagnostic and therapeutic approaches to dementia and parkinsonism. The recognition of synuclein and ubiquitin markers in dementia resulted in the reclassification of patients previously considered as affected by Alzheimer Disease (AD) and Vascular Dementia (VaD), and there is now agreement that DLB is the second most common cause of dementia in elderly population: its prevalence is reported to be in the 25-43% range in different studies. DLB is clinically characterized by the presence of prominently dysexecutive dementia (frontal lobe or subcortical dementia according to earlier classification [1]), cognitive fluctuations, consisting of remitting-relapsing episodes of blunted conscience reaching levels of stupor, by the occurrence of visual hallucinations and delusions, by parkinsonian motor signs and hypersensitivity to neuroleptic treatment, ranging from worsening of parkinsonism to the possible lethal neuroleptic-malignant syndromes [2]. Yet, variances of presentation and overlapping symptoms with AD and Fronto-Temporal lobe Degeneration (FTD), could be misleading in the process of addressing a clinical diagnosis with consequent therapeutic risks(e.g. introducing neuroleptic treatments in patient with DLB), or economic costs (e.g. addressing patients with DLB to treatment protocols dedicated to AD patients, based on vaccines or antibodies against amyloid proteins, a neuropathological feature of AD). It is evident the stringent need for improvement of reliable diagnostic tools (u.e. biomarkers) to differentiate the diseases associated with dementia. In 2010 the National Institute of Health, NIH, held a symposium focused on the development of possible biomarkers for DLB. Among the different suggested biomarkers, neurophysiological assessments were reconsidered, as a large amount of neurophysiological studies had been devoted to AD and PD, whose characteristics are shared by DLB. www.intechopen.com Neuroimaging for Clinicians -Combining Research and Practice 300We contributed to several studies on this argument along the years, and in the present chapter we discuss the role of clinical neurophysiological studies in DLB in comparison with other disorders. The essential background of our original studies laid in the fact that most historical studies were performed when the DLB clinical entity was unknown and therefore some of the past results were marred by absent recognition of this clinical entity. Synucleinopathies: Dementia with lewy bodiesSynucleinopathies comprise a diverse groups of neurodegenerati...

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Section: Neuroimaging For Clinicians -Combining Research and Practicesupporting

confidence: 78%

Section: Quantitative Eeg:qeegmentioning

confidence: 98%

Is There a Place for Clinical Neurophysiology Assessments in Synucleinopathies?

Onofrj¹,

Bonanni²,

Thomas³

et al. 2011

Neuroimaging for Clinicians - Combining Research and Practice

View full text Add to dashboard Cite

show abstract

“…Recent clinical studies of compressed spectral array EEG have shown a reduction in higher frequency (0 or a frequency range of 4 to 13 Hz) energy in deep coma (26,27), and a correlation of the reappearance of these frequencies with good recovery. All of the head-injured subjects in the present study had GCSs of 8 or less and were, by accepted definition (13), deeply comatose.…”

Section: Discussionmentioning

confidence: 99%

Auditory Brain Stem Response Spectral Content in Comatose Head-Injured Patients

Hall

1986

Ear and Hearing

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Auditory brain stem response (ABR) spectral content was analyzed for 25 normal subjects and 70 comatose, severely headinjured subjects. The normal ABR spectrum was characterized by energy peaks in three main regions: 0 to 200 Hz, 500 to 600 Hz and 900 to 1000 Hz. Head-injured subjects, in contrast, showed less overall ABR spectral energy. Even head-injured subjects with normal ABR interwave latency values had reduced spectral energy in comparison to the normal group. Among these subjects, there were differences in spectral content for subjects with good neurologic outcome versus those who died within 2 weeks post injury. Finally, head-injured subjects with abnormal interwave latency intervals typically showed distinctive spectral patterns. This subject group demonstrated energy peaks in frequency regions which, for the other groups, were void of energy peaks. Rationale for further study of ABR spectral content is offered.The auditory brain stem response (ABR) is a complex electrophysiologic waveform typically recorded in the time domain. Analysis of ABR data usually involves determination of the absolute latency and amplitude of major wave components, and often relative latency or amplitude measures such as the wave I-V latency interval or the wave V/I amplitude ratio [see Hall (1) for review]. By means of spectral analysis techniques, it is now also possible with commercially available instrumentation to calculate the frequency composition of an ABR waveform. That is, ABR amplitude is described in the frequency domain rather than the customary time domain. ABR spectral analysis is usually done with fast Fourier transformation which deconvolutes a complex waveform into its frequency components (2, 3).There is a modest literature on the spectral content of the ABR in persons with normal peripheral and central nervous system (CNS) status (4-1 1). Reported data on the ABR spectrum are based on normative studies with a This work was in part supported by the 1985 Braintree Award for Outstanding Research in Head Injury.cumulative total of less than 20 subjects (5-10). There is general agreement that the ABR consists of a relatively high energy, low-frequency component (1 50 Hz and below), a component in the 500 to 600 Hz region, and a relatively high-frequency component in the 900 to 1100 Hz region, and that spectral energy is minimal above 2000 Hz. Less clear is the relationship of ABR spectral characteristics to the individual wave components recorded in the time domain, e.g., waves I, 111, and V. Kevanishvili and Aphonchenko (7), for example, concluded from digital filtering and power spectral analysis techniques that the major energy contributions of the ABR waves were 400 to 1000 Hz for waves I and 11, 100 to 900 Hz for wave 111, and 100 to 500 Hz for waves IV through VI. Using similar techniques, Suzuki et a1 (10) supported these. findings. Boston (5) studied ABR spectrum with digital filtering techniques. He attributed the high-frequency spectral component (900 to 1100 Hz) to the early ABR waves (I, 11, 111), th...

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“…A routine EEG is not sufficient to exclude a variability in EEG activity [2], and an alternating or cycling EEG suggests a more benign outcome than an invariant record. This has been confirmed in patients with head trauma and anoxia [8,10]. CSA studies may also be used to identify normal sleep patterns or normal circadian cycles, which suggest a more favorable prognosis [2].…”

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confidence: 76%

“…CSA provides a three-dimensional display of EEG data and uses a digital computer that concomitantly presents other physiological variables (e.g., peak, median power, and spectral edge frequencies; frequency bin activity totals; frequency bin ratios; intracranial and blood pressure; and electrocardiogram [2,7,8].…”

mentioning

confidence: 99%

Neurophysiological Monitoring in the Intensive Care Unit

Cascino

1988

J Intensive Care Med

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Electroencephalography and evoked potentials are ob jective and reproducible studies used in the intensive care unit as an extension of a neurological examination. The techniques can be performed serially at the bedside and are used diagnostically in the evaluation of patients with altered states of consciousness, seizure disorders, and threatened cerebral perfusion. EEG is used in the determination of brain death. Auditory evoked poten tials have been demonstrated to be an effective method of delineating a peripheral auditory dysfunction in neo natal patients. Potential uses of electroencephalography and evoked potentials include predicting outcome and monitoring a patient's response to therapeutic interven tion. Importantly, these studies may provide the only assessment of central nervous system function when the neurological examination is precluded (e.g., barbitu rate-induced coma).

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EEG monitoring of clinical coma

Cited by 61 publications

References 0 publications

Is There a Place for Clinical Neurophysiology Assessments in Synucleinopathies?

Is There a Place for Clinical Neurophysiology Assessments in Synucleinopathies?

Auditory Brain Stem Response Spectral Content in Comatose Head-Injured Patients

Neurophysiological Monitoring in the Intensive Care Unit

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