PubMed Health⌕ Search

Biomedical subjects

J Mellers

Publications and source records attributed to J Mellers.

11 recordsLinked to original sources
PubMed2004

Schizophrenia-like psychosis arising de novo following a temporal lobectomy: timing and risk factors.

OBJECTIVES: To clarify risk factors for the development of schizophrenia-like psychotic disorders following temporal lobectomy, and to explore the possibility that the early postoperative period is a time of high risk for the onset of such chronic psychotic disorders. METHODS: Patients who developed schizophrenia-like psychosis were identified from a series of 320 patients who had a temporal lobectomy for medically intractable epilepsy. The relationship of their disorders to both the operation and subsequent seizure activity was examined. Using a retrospective case-control design, risk factors for the development of schizophrenia-like psychosis were established. RESULTS: Eleven patients who developed schizophrenia-like psychosis postoperatively were identified and compared with 33 control subjects who remained free of psychosis postoperatively. The onset of de novo psychotic symptoms was typically in the first year following the operation. No clear relationship between postoperative seizure activity and fluctuations in psychotic symptoms emerged. Compared with the controls, patients who become psychotic had more preoperative bilateral electroencephalogram (EEG) abnormalities, pathologies other than mesial temporal sclerosis in the excised lobe and a smaller amygdala on the unoperated side. CONCLUSIONS: Temporal lobectomy for medically intractable epilepsy may precipitate a schizophrenia-like psychosis. Patients with bilateral functional and structural abnormalities, particularly of the amygdala, may be at particular risk for the development of such psychoses.

Adolescent↗
PubMed2000

Schizophrenia, temporal lobe epilepsy and psychosis: an in vivo magnetic resonance spectroscopy and imaging study of the hippocampus/amygdala complex.

BACKGROUND: We have used proton magnetic resonance imaging and spectroscopy to measure hippocampus/amygdala volumes and anterior hippocampal metabolite concentrations (N-acetyl aspartate (NAA), creatine/phosphocreatine and choline) in subjects with temporal lobe epilepsy (TLE), schizophrenia and in normal controls. METHOD: Four groups of right-handed patients were selected: 12 with TLE and psychosis (EP), 12 with TLE and no psychosis (ENP), 26 with schizophrenia, and 38 normal controls. Imaging and spectroscopy were performed with a 1.5T Signa GE scanner. RESULTS: The schizophrenia group showed a significant left-sided reduction in all metabolites. In the epilepsy groups NAA was reduced bilaterally. The NAA reduction in the EP group was greater than in the ENP group, especially on the left, although the result did not reach significance. Total hippocampus/amygdala volumes showed no significant differences in any of the groups when compared with normal controls. When compared with controls significant, specific regional volume reductions were present bilaterally in the EP group and in the left hippocampus/amygdala in schizophrenia. The regional volume reduction found in schizophrenia was also present in EP but not in ENP. CONCLUSION: Spectroscopic abnormalities were more pronounced in the epilepsy groups and were bilateral, and abnormalities in schizophrenia were left sided. Specific regional hippocampus/amygdala volume reductions were more marked in the EP group and were bilateral. Left-sided regional volume reduction identified in the dominant hemisphere of schizophrenics was also present in EP patients, but not in ENP, suggesting that this region in the left temporal lobe may be significant in the aetiology of psychosis. This is further supported by the predominantly left-sided NAA reduction in schizophrenia. High resolution morphometric studies may identify specific regions of the brain associated with the development of psychosis.

Adult↗
PubMed2000

Dissociation, hypnotizability, coping styles and health locus of control: characteristics of pseudoseizure patients.

Although literature in this area is relatively sparse, the occurrence of psychogenic non-epileptic seizures (pseudoseizures) has been linked to stress, anxiety and possible dissociative tendencies. An association between dissociation and hypnotic susceptibility has also been proposed and dissociative tendencies have themselves been found to relate to the use of emotion-focused coping strategies. In order to investigate the hypothesis that pseudoseizure patients may exhibit higher levels of dissociation, a more emotion-focused coping style, and greater hypnotic susceptibility than the general population, the questionnaire responses of 20 patients with pseudoseizures were compared with those obtained from a non-clinical control group. As predicted, pseudoseizure patients demonstrated some evidence of higher levels of dissociation and escape-avoidance coping strategies. They also expressed a greater belief in external control over health and higher depression scores, compared to the control group, but the previously reported elevation in hypnotizability scores in the pseudoseizure patients was not found. Possible explanations for this pattern of results are discussed.

Adaptation, Psychological↗
PubMed1996

Statistical methods of estimation and inference for functional MR image analysis.

Two questions arising in the analysis of functional magnetic resonance imaging (fMRI) data acquired during periodic sensory stimulation are: i) how to measure the experimentally determined effect in fMRI time series; and ii) how to decide whether an apparent effect is significant. Our approach is first to fit a time series regression model, including sine and cosine terms at the (fundamental) frequency of experimental stimulation, by pseudogeneralized least squares (PGLS) at each pixel of an image. Sinusoidal modeling takes account of locally variable hemodynamic delay and dispersion, and PGLS fitting corrects for residual or endogenous autocorrelation in fMRI time series, to yield best unbiased estimates of the amplitudes of the sine and cosine terms at fundamental frequency; from these parameters the authors derive estimates of experimentally determined power and its standard error. Randomization testing is then used to create inferential brain activation maps (BAMs) of pixels significantly activated by the experimental stimulus. The methods are illustrated by application to data acquired from normal human subjects during periodic visual and auditory stimulation.

Acoustic Stimulation↗
PubMed1995

Activation of area V5 by visual perception of motion demonstrated with echoplanar MR imaging.

Cortical activation in visual association areas known to be responsible for the perception of motion was investigated in two volunteers who viewed a projected animated cartoon periodically "run" and "frozen" during collection of echoplanar MR images. Ten axial, contiguous, 5 mm thick, T2-weighted, gradient-echo images (TE 40 ms, TR 3000 ms) depicting BOLD contrast were acquired through the occipital lobe using a GE Signa 1.5 T system with an advanced NMR operating console. Images were analysed by time series regression modelling estimating power in the MR signal at the ON-OFF frequency of motion. Highly significant activation in response to motion perception was identified in both subjects bilaterally in area V5.

Echo-Planar Imaging↗
PubMed1995

Magnetic resonance imaging volumetric measurements of the superior temporal gyrus, hippocampus, parahippocampal gyrus, frontal and temporal lobes in late paraphrenia.

Quantified magnetic resonance measurements were made of superior temporal gyrus, parahippocampal gyrus, hippocampal, frontal and temporal lobe volumes and of the planar area of the thalamus and basal ganglia structures in 47 late paraphrenic patients and 33 healthy elderly controls. The late paraphrenics were divided into 31 schizophrenics and 16 patients with delusional disorder according to ICD-10 guidelines. Patients with delusional disorder tended to have smaller left temporal volumes compared with control subjects and patients with schizophrenia, but this difference failed to reach accepted levels of statistical significance after correction for the effects of multiple statistical comparisons, age and total brain size. Physiological right-left asymmetry, reported for temporal and frontal lobe volumes, was present in control, schizophrenic and delusional disorder subjects but delusional disorder patients had a significantly greater degree of temporal lobe asymmetry. The results add to the evidence for heterogeneity among late-onset psychoses and emphasize the subtle nature of any structural brain abnormalities in these patients.

Aged↗
PubMed1990

Risk factors of female HIV-seropositive patients attending the clinic for sexually transmitted diseases at St Mary's Hospital, London.

Of 3450 women tested for antibodies to human immunodeficiency virus HIV-1 and HIV-2 between September 1985 and July 1989, 61 were positive (1.8%). Twenty-seven of these (44%) were presumed to have acquired their HIV infection by heterosexual contact and 23 (38%) were intravenous drug addicts. In geographical origin, 23 (38%) of the patients were from the UK and 19 (31%) from Africa. Amongst these 61 women, 2 (3%) have since died, one committed suicide and one was suspected of committing suicide.

Adolescent↗