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Biomedical subjects

M R Nuwer

Publications and source records attributed to M R Nuwer.

At least 37 records · Page 2Linked to original sources
PubMed1998

New developments.

Explore the source record for details and available documents.

Electroencephalography↗
PubMed1998

The Health Care Financing Administration's new examination documentation criteria: minimum auditing standards for the neurologic examination to be used by Medicare and other payors. Report from the American Academy of Neurology Medical Economics and Management Subcommittee.

Medicare recently announced the adoption of minimum documentation criteria for the neurologic examination. These criteria are added to existing standards for the history and medical decision-making. These criteria will be used in compliance audits by Medicare and other payors. Given the current federal initiative to eliminate fraud in the Medicare program, all neurologists need to comply with these standards. These criteria are for documentation only. Neurologic standards of care require a more complex and diverse examination pertinent to the problem(s) under consideration. Further guidance as to the content of a neurologic evaluation is outlined in the article "Practice guidelines: Neurologic evaluation" (Neurology 1990; 40: 871). The level of history and examination required for specific services is defined in the American Medical Association current procedural terminology book. Documentation standards for examination of children are not yet defined.

Aged↗
PubMed1998

Pentoxifylline is not a promising treatment for multiple sclerosis in progression phase.

Fourteen MS patients took pentoxifylline at varying doses for up to 24 months. In vitro production of tumor necrosis factor alpha was reduced in patients taking 2,400 to 3,200 mg/day of pentoxifylline for 12 weeks or more. Twelve of the 14 patients experienced worsening of the disease during the study according to clinical, MRI, or visual evoked potential criteria. These results provide no hint of efficacy for pentoxifylline as a treatment for MS in progression phase.

Adult↗
PubMed1997

Intraoperative dermatomal evoked potential monitoring fails to predict outcome from lumbar decompression surgery.

STUDY DESIGN: Thirty-three patients with single-level, unilateral lumbosacral radiculopathy underwent micro-decompression and intraoperative dermatomal evoked potential monitoring. Side-to-side latency asymmetry was calculated. A criteria for "abnormal" was defined. Intraoperative dermatomal evoked potentials were obtained before and after decompression. The changes were correlated with clinical outcome at the 3-month follow-up examination. OBJECTIVES: To determine whether intraoperative dermatomal evoked potential latency asymmetry confirms nerve root compression and whether an improvement of latency asymmetry after decompression predicts a good clinical outcome. SUMMARY OF BACKGROUND DATA: Intraoperative dermatomal evoked potential has been proposed as a test to assess the adequacy of nerve root decompression. Initial reports suggested improvement of dermatomal evoked potential amplitude and latency after decompression. The clinical efficacy is controversial because of its technical difficulty and inherent variation. METHODS: Cervical recording was chosen to reduce the effects of anesthesia. The asymptomatic nerve root was used as a control. Quality of the tracings was determined by evoked potentials-to-noise amplitude ratio. Clinical outcome was based on patient's pain relief and satisfaction. RESULTS: Tracings of acceptable quality were obtained at baseline in 57.6% (19 of 33) of patients. A side-to-side latency asymmetry > 5% was defined as abnormal. Before decompression, 68.4% (13 of 19) of patients had an abnormal dermatomal evoked potential. After decompression, latency asymmetry returned to normal in every patient. Clinical outcome was good or excellent in 13 patients, fair in four patients, and poor in two patients. Dermatomal evoked potential latency improvements were not related to variation in clinical outcome. CONCLUSIONS: Intraoperative dermatomal evoked potential monitoring is technically demanding. Finding reproducible potentials is difficult. More research is necessary before general use of dermatomal evoked potentials for monitoring nerve root decompression.

Adult↗
PubMed1997

Neurophysiologic surgical monitoring staffing patterns in the USA.

Staffing patterns for intraoperative EEG and somatosensory evoked potential monitoring were assessed in a survey of 150 US board certified clinical neurophysiologists. Whether or not a clinical neurophysiology physician needs to be in the operating room throughout monitoring has been a point of disagreement and debate. The data here provide evidence that most US clinical neurophysiologists send non-physician staff to monitor EEG during carotid endarterectomies. Similar results were found for somatosensory evoked potential spinal cord monitoring during scoliosis procedures. By describing current staffing practices, these data can promote a more informed debate on this controversial topic.

Anesthesiology↗
PubMed1997

Early detection of vasospasm after acute subarachnoid hemorrhage using continuous EEG ICU monitoring.

The neurologic morbidity of delayed ischemic deficits from vasospasm following aneurysmal subarachnoid hemorrhage (SAH) continues to be the most debilitating complication from this devastating illness. Neurologic critical care is focused on recognition and treatment of these secondary insults but often the treatment is withheld until an irreversible deficit becomes manifest. Continuous EEG (cEEG) monitoring provides a unique potential to recognize early secondary insults and offers an opportunity for early intervention. We studied 32 SAH patients using cEEG and trending of the quantitative measure, relative alpha (RA), to determine if reductions in RA variability occurred with documented vasospasm. In 19/19 patients with angiographically documented vasospasm, we found that RA variability was decreased by a mean of two grades and improved with resolution of vasospasm. In 10/19 this reduction in RA variability preceded the diagnosis of vasospasm by a mean of 2.9 days (SD 1.73). The positive predictive and negative predictive values are 76% and 100%, respectively. Non-diagnostic clinical signs at the time of RA variability reduction and vasospasm were present in 12/19 patients. Thus decreased RA variability is able to provide early detection of neurologic complications such as vasospasm in patients before clear clinical symptoms and signs occur.

Adult↗
PubMed1996

Quantitative EEG analysis in clinical settings.

Quantitative EEG techniques are becoming more available. Eventually, all EEG will be digital. Various digital utility programs can help even now with storage and viewing the polygraph EEG itself. Techniques of frequency analysis, topographic mapping and discriminant functions are also available but have limited clinical use. Applications as a monitoring tool and careful analysis of epileptic spikes have been shown some promise but need further study to identify their proper clinical roles.

Aged↗
PubMed1996

Spike detection. I. Correlation and reliability of human experts.

A panel of 5 experienced electroencephalographers detected spikes in EEG trials from 40 epilepsy patients and 10 control subjects. 1952 spikes were detected, and detailed attribute scores were recorded. Statistics from the theory of measurement error are utilized to quantify the reliability and difficulty of the study. An extension of the Pearson correlation coefficient, called the detection correlation coefficient, is derived and used in recognition of the fact that readers agree on numerous non-spike regions. Spike perception is modeled with both dichotomous and continuous values. as expected, the study reliability is higher when using the continuous values. Standard sensitivity and specificity definitions are extended and applied to continuous-valued spike perception. A database of "panel scores" was created from the 5 reader scorings by merging spikes within 75 msec on each side. The average inter-reader correlation is 0.79 with a corresponding reliability of 0.95. Average spike attributes are calculated, and the resulting database can serve as a "gold standard" for testing computer algorithms or other readers.

Action Potentials↗
PubMed1995

Somatosensory evoked potential spinal cord monitoring reduces neurologic deficits after scoliosis surgery: results of a large multicenter survey.

Neurologic deficits were compared to somatosensory evoked potential (SEP) spinal cord monitoring in a survey of spinal orthopedic surgeons. Experienced SEP spinal cord monitoring teams had fewer than one-half as many neurologic deficits per 100 cases compared to teams with relatively little monitoring experience. Experienced SEP monitoring teams also had fewer neurologic deficits than were seen in previous surveys of this group. Definite neurologic deficits, despite stable SEPs (false negative monitoring), occurred during surgery in only 0.063% of patients. Factors independently associated with fewer neurologic deficits also included the surgeon's years of experience in orthopedic surgery and the use of the wake-up test. Other technical survey results are also presented here. These results confirm the clinical efficacy of experienced SEP spinal cord monitoring for prevention of neurologic deficits during spinal surgery such as for scoliosis.

Electric Stimulation↗
PubMed1995

Intraoperative monitoring during selective posterior rhizotomy: technique and patient outcome.

We evaluated intraoperative electromyographic (EMG) results among 110 pediatric patients with spastic cerebral palsy who underwent selective posterior rhizotomy. We analyzed surgical outcomes for 60 of these patients who returned for follow-up assessment between 4 and 17 months postoperatively. Reduction in muscle tone (resistance to passive movement), increased range of motion and improvements in functional skills were seen at follow-up. To control for possible changes due to development, participation in therapy, or instability of measurements, 30 rhizotomy patients were evaluated twice during a baseline period of several months prior to surgery. No significant changes were found between these two measurement sessions during the baseline control period suggesting that the rhizotomy surgery itself caused the postoperative improvements. These intraoperative EMG monitoring techniques have been adopted at many other centers but variations in specific methods and EMG criteria have developed subsequently among major hospitals where selective posterior rhizotomy is performed. These variations in neurophysiologic methods and recent controversy about the usefulness of such intraoperative EMG monitoring created a need for us to publish our standard EMG selection technique. We describe here, in detail, methods for nerve rootlet testing and selection.

Cerebral Palsy↗
PubMed1994

A comparison of quantitative electroencephalography, computed tomography, and behavioral evaluations to localize impairment in patients with stroke and transient ischemic attacks.

Brain computed tomography and a structured behavioral assessment provided a better correlation than did quantitative electroencephalography to the presence of mild stroke or transient ischemic attacks in 21 patients. When electroencephalography did not correlate well, it tended to localize too laterally or miss deep lesions. Computed tomography did not identify 2 lesions when done early after disease onset. No test was uniformly more sensitive or accurate than others. They may complement each other.

Activities of Daily Living↗
PubMed1994

Electroencephalograms and evoked potentials. Monitoring cerebral function in the neurosurgical intensive care unit.

Electroencephalographic and evoked potential testing are valuable clinical tools in the ICU. They can detect subclinical neurologic impairment, identify locations of dysfunction, and help establish the nature of some kinds of problems. Continuous monitoring provides a valuable technique for identifying nonconvulsive seizures, as well as for detecting certain complications early enough to intervene and prevent permanent sequelae. Knowledgeable clinicians can use these tools to benefit ICU patient care greatly.

Brain↗