Biomedical subjects

R S Delamont

Publications and source records attributed to R S Delamont.

6 recordsLinked to original sources

PubMed2002

Neurophysiologic analysis of neuromuscular symptoms in UK Gulf War veterans: a controlled study.

BACKGROUND: UK veterans who were deployed to the Gulf in 1990 to 1991 reported higher prevalence of neuromuscular symptoms. OBJECTIVE: To investigate whether these Gulf War-related symptoms were associated with objective evidence of neuromuscular dysfunction. METHODS: Forty-nine Gulf War veterans with more than four neuromuscular symptoms (Gulf-ill), 26 Gulf-well veterans, 13 symptomatic Bosnian veterans (Bosnia-ill), and 22 symptomatic veterans who were not deployed to the Gulf (Era-ill) underwent detailed neurophysiologic assessment: nerve conduction studies, quantitative sensory and autonomic testing, and concentric needle and single-fiber electromyography (EMG). RESULTS: Nerve conduction studies detected carpal tunnel syndrome in two Gulf-ill, two Gulf-well, one Bosnia-ill, and three Era-ill veterans. Ulnar neuropathy was detected in one Gulf-ill and two Era-ill veterans. However, results of detailed nerve conduction studies of the Gulf-ill veterans were comparable with results observed in the other three groups. Quantitative sensory and autonomic assessments also failed to show any specific abnormalities in the Gulf-ill group. Similarly, quantitative assessment of concentric needle and single-fiber EMG detected no chronic denervation or myopathic changes or any abnormalities of neuromuscular transmission in the Gulf-ill veterans. CONCLUSION: Gulf War-related neuromuscular symptoms are not associated with specific impairments of peripheral nerves, neuromuscular junctions, or skeletal muscles.

Adult↗

PubMed1999

Changes in a measure of cardiac vagal activity before and after epileptic seizures.

In previous studies of the relationship between the cardiac autonomic activity and seizures, assessment of autonomic changes has relied on alterations in heart rate or R-R intervals. We have used a recently developed continuous index of cardiac parasympathetic activity (CIPA) to examine 20 seizures in 10 patients during pre-surgical evaluation in a video-telemetry unit. The patients had localization related seizures due to non-progressive pathology and both complex partial seizures (CPS) and complex partial with secondary generalised tonic clonic seizures (STCS) were examined. Mean CIPA prior to the onset of STCS was elevated above normal values and fell significantly to previously established normal values following the seizure. CPS were not associated with elevated mean CIPA pre- or post-seizure. STCS were associated with a reduction in anti-convulsant dosage and with elevation of pre-ictal CIPA. We propose that elevation of cardiac parasympathetic activity pre-ictally may be a marker for secondary generalisation of seizures.

Adult↗

PubMed1999

Periodicity of a noninvasive measure of cardiac vagal tone during non-rapid eye movement sleep in non-sleep deprived and sleep-deprived normal subjects.

Cyclic alternating pattern (CAP) of microarousals reported in EEG studies is now regarded as an integrating mechanism for the different parts of the central nervous system including the autonomic system. A recently developed continuous index of cardiac parasympathetic activity (CIPA) can be time locked to the EEG allowing the relationship between EEG and autonomic changes to be studied in sleep. Eleven normal subjects were studied for evidence of periodicity in CIPA in non-REM sleep, five of whom had been sleep deprived. Fast Fourier's transformation of the CIPA data confirmed its periodicity with four frequency peaks in the range of 0.015 to 0.3 Hz. The frequency peaks previously reported as caused by respiration, Mayer waves and vasomotor thermoregulatory activity, were within what we called the alpha and beta rhythms of CIPA. There was an additional very slow peak not previously described and we called it the gamma rhythm. It covered the frequency range below 0.03 Hz. The gamma rhythm was the largest of all peaks in CIPA rhythms and its magnitude increased further in sleep-deprived subjects, but it invariably decreased during stage 4 sleep in both groups. Bursts of alpha waves in the EEG recorded concomitantly with CIPA in stage 1 sleep were associated with both peaks and troughs of the gamma rhythm. These results support previous proposals that cyclic alternating pattern in the EEG may be an integrating mechanism associated with functions of the central nervous system, and we have shown here its relationship with CIPA. Because cyclic alternating pattern can also be measured in CIPA, clinical exploitation of this phenomenon could include monitoring of epilepsy, studies of the effects of drug therapy, and assessment of other sleep disorders. All these are known to affect cyclic patterns of sleep EEG.

Adult↗

PubMed1998

Sleep deprivation and its effect on an index of cardiac parasympathetic activity in early nonREM sleep in normal and epileptic subjects.

The effect of 24-hour sleep deprivation on cardiac vagal tone during the first 90 minutes of sleep was studied in 16 subjects using a new real-time index of cardiac parasympathetic activity. The level of cardiac vagal tone in subjects who were sleep deprived was more than doubled that in non-sleep-deprived subjects during sleep stage 0 immediately prior to the onset of sleep stage 1. The mean cardiac vagal tone fell significantly (p < 0.01), from a high level of 19.2 arbitrary units of a linear vagal scale (LVS) to 10 units on reaching slow-wave sleep stage 4 in sleep-deprived epileptic subjects, There was a similar fall in cardiac vagal tone from 18.7 units to 12 units in the LVS in sleep-deprived normal subjects, but this was not statistically significant. There was no change in the mean vagal tone of non-sleep-deprived normal subjects. We propose that the cardiac vagal tone can be used as an objective index of sleep propensity.

Adult↗

PubMed1989

Posterior cortical atrophy.

Two patients had a steadily progressive disorder of higher cortical function dominated by the early development of cortical visual deficits. In one, a right visual inattention progressed over a period of 2 years to a complete right homonymous hemianopia and relative left inferior quadrantanopia. In the second case, blind in the left eye for unrelated reasons, a temporal field loss was noted at presentation in the right eye, with the subsequent development of field loss in the inferior nasal quadrant on that side. Features of Balint's syndrome developed in both patients, with sticky fixation, ocular dysmetria and simultanagnosia. Prominent associated features were progressive dysmnesia, dyscalculia, ideomotor apraxia and spatial disorientation. Abstract reasoning, speech function and insight were all well preserved. MRI and CT scans revealed no focal abnormalities. These cases are similar to the 5 recently described by Benson et al. The pathological basis is unknown but may be an atypical form of Alzheimer's disease.

Atrophy↗

PubMed1989

Traumatic hypoglossal nerve palsy.

Isolated fracture through the atlanto-occipital region is not common and can easily be missed, clinically and radiologically. The long-term outlook from an isolated twelveth nerve palsy has been good in our experience of two cases.

Adult↗