An infrared camera provides a rapid method of assessing the effective distribution of RF energy on the surface and in the depth of a split phantom. The reduced emissivity appears to cause no problem for qualitative studies and allows the possibility of studying the effects of combined fields or surveying applicators for stray leakage.

Infrared Rays↗

PubMedDate not supplied

Quantitative surface EMG in the diagnosis of neuromuscular disorders.

This paper describes a non-invasive quantitative method for the diagnosis of neuromuscular disorders using surface EMG (sEMG). We found sEMG to be a reliable method that can be used to differentiate neuropathic and myopathic patients from the normal subjects. The multivariate discriminant analysis of sEMG data assisted in separating myopathic from neuropathic disorders. Nevertheless sEMG is not robust enough to replace needle EMG as a stand-alone diagnostic tool. However quantitative sEMG that is described in this paper could be adopted as a simple, rapid and non-invasive technique to be used in the out patients clinic by EMG-naive clinicians as a screening method for neuromuscular disorders, before referring the patients for detailed clinical neurophysiological examinations.

Differential Threshold↗

PubMedDate not supplied

Monitoring sedation levels by EEG spectral analysis.

Real-time electroencephalographic power spectra were obtained for a group of 37 volunteers undergoing sedation with enflurane at different concentrations in air. In part one, 17 subjects were given 0.5%, 0.75%, and 1.0% for 4 min at each level, and recovery after 5 min was assessed by the Trieger method. There was considerable variation in subject response to the different doses, but adequate sedation was indicated by the presence of a strong alpha rhythm (9-11 Hz) and suppression of frequencies below 5 Hz. Overdose was indicated by an initial shift in the alpha frequency to a lower value (6-7 Hz) followed by the appearance of delta waves (0.5-4 Hz) and loss of alpha waves. In part two, 20 volunteers inhaled enflurane at 0.5% for 10 min to allow adequate absorption, followed by a 10-min recovery period. Equal numbers showed sedation or a failure to respond to enflurane at this concentration. In the responders, sedation was accompanied by a marked shift in the ratio of the power in two frequency bands: 1-4 Hz and 8-12 Hz. Progress of the frequency band power ratio followed closely the state of the subject into sedation, overdose, and recovery. This measure was further improved by the use of multivariate analysis, which showed good discrimination of the alert, sedated, and overdosed states of the subject.

Adult↗