Somatization disorder (SMD) is a chronic condition characterized by multiple complaints which are not due to any apparent organic illness but frequently involve pain. This study employs ...computer-aided imaging technologies to examine brain function in thousandths of a second (event-related brain potentials) and over a number of minutes (regional cerebral blood flow). Fourteen patients with SMD and 14 normal controls were investigated. Results from both studies suggest that patients with SMD have a dysfunction in the processes of attention, compared to normal controls.
A 43 year old man with a traumatic amnesic syndrome experienced only a brief, if any, loss of consciousness following an injury to the head. Four years after this injury, his results on standard ...psychometric assessment were normal. Long-latency evoked response potentials results were normal, and the neurological examination and computed tomography scans were unhelpful in explaining his amnesic symptoms. He had no history of alcohol abuse, yet his neuropsychological profile was that of a Korsakoff-like amnesia with frontal lobe features. Magnetic-resonance images demonstrated evidence of extensive frontal lobe damage, while cerebral blood flow studies provided additional evidence of bilateral frontal lobe dysfunction. The case highlights the need for those giving opinions in medico-legal head trauma cases to go beyond a reliance on routine indicators, such as duration of coma, results of standard psychometric assessment and computed tomography scans, to more specialised neuropsychological evaluations and magnetic-resonance imaging scans.
Dynamic spectral analysis of event-related potentials Melkonian, Dmitriy; Gordon, Evian; Rennie, Christopher ...
Electroencephalography and clinical neurophysiology,
04/1998, Volume:
108, Issue:
3
Journal Article
This paper presents a new method for the identification of individual event related potential (ERP) components in both frequency and time domains. Using the similar basis function (SBF) algorithm the ...method provides a time to frequency transform, representing a frequency domain equivalent of the component waveform. Notable features of the SBF algorithm are that it allows for unevenly spaced sampled functions in both the time and frequency domains, and estimates of spectral densities are obtained by numerical computation of finite Fourier integrals. Application of this method to ERP data from 20 normal subjects demonstrated a similar shape of component amplitude frequency characteristics for traditional late component waveforms (N
1, P
2, N
2 and P
3). On this basis, a low-frequency band was found where the component amplitude frequency characteristic was described by a Gaussian function, while the component phase frequency characteristic was a linear function of frequency. These relationships are interpreted as frequency domain equivalents of the component. Transformed to the time domain, they provided an analytical description of the ERP as the sum of positive- and negative-going monopolar waves. The study points to similar mechanisms underlying these component waveforms, and analytically defines dynamic properties for the components both in the frequency and time domains.
This study examines the possibility that Type A behaviour is related to physique, and thus, is secondary to physique as a risk factor for coronary heart disease (CHD). Scores on a modified version of ...the 1966 Jenkins Activity Survey were correlated with a number of physical parameters. Age was found to have the highest correlation of -0.177. When the effects of age were adjusted for, only 7.1% of variation in JAS scores was explained by the body measurements used to define physique. In addition, when high and low scorers on the JAS were compared, no significant differences were found between the groups on any of the body measurements. Since this study found no significant relationship between JAS scores and physique, the results do not controvert the supposition that Type A behaviour is an independent risk factor for CHD.
This study attempted to increase the reliability of predicting the normal latency of the P3 component in elderly adults. It was hypothesized this would allow a more accurate distinction to be made ...between normal adults (n = 20) and patients with dementia (n = 19) on the basis of observed P3 latencies. Two models for predicting latency were assessed. The first, which used age alone as a predictor, explained 18% of the normal variation in latency and misclassified 40% of the patients. The second model, which incorporated scores on psychometric tests, explained 74% of latency variation and misclassified 20% of the patients. Scores on the Similarities subtest of the WAIS and the Rey Auditory Verbal Learning Test, however, correctly identified 92% of the patients. This finding casts doubt on the justification of the P3 latency measures to diagnose dementia.
