Near death experiences, cognitive function and psychological outcomes of surviving cardiac arrest.

Cardiac arrest is associated with a number of cognitive processes as well as long term psychological outcomes. Recent studies have indicated that approximately 10-20% of cardiac arrest survivors report cognitive processes, including the ability to recall specific details of their resuscitation from the period of cardiac arrest. In addition it has been demonstrated that these cognitive processes are consistent with the previously described near death experience and that those who have these experiences are left with long term positive life enhancing effects. There have also been numerous studies that have indicated that although the quality of life for cardiac arrest survivors is generally good, some are left with long term cognitive impairments as well as psychological sequelae such as post-traumatic stress disorder. This paper will review near death experiences, cognitive function and psychological outcomes in survivors of cardiac arrest.

The human primary somatosensory cortex response contains components related to stimulus frequency and perception in a frequency discrimination task.

Somatosensory stimulation of primary somatosensory cortex (SI) using frequency discrimination offers a direct, well-defined and accessible way of studying cortical decisions at the locus of early input processing. Animal studies have identified and classified the neuronal responses in SI but they have not yet resolved whether during prolonged stimulation the collective SI response just passively reflects the input or actively participates in the comparison and decision processes. This question was investigated using tomographic analysis of single trial magnetoencephalographic data. Four right-handed males participated in a frequency discrimination task to detect changes in the frequency of an electrical stimulus applied to the right-hand digits 2+3+4. The subjects received approximately 600 pairs of stimuli with Stim1 always at 21 Hz, while Stim2 was either 21 Hz (50%) or varied from 22 to 29 Hz in steps of 1 Hz. Both stimuli were 1 s duration, separated by a 1 s interval of no stimulation. The left-SI was the most consistently activated area and showed the first activation peak at 35-48 ms after Stim1 onset and sustained activity during both stimulus periods. During the Stim2 period, we found that the left-SI activation started to differ significantly between two groups of trials (21 versus 26-29 Hz) within the first 100 ms and this difference was sustained and enhanced thereafter (approximately 600 ms). When only correct responses from the above two groups were used, the difference was even higher at later latencies (approximately 650 ms). For one subject who had enough trials of same perception to different input frequencies, e.g. responded 21 Hz to Stim2 at 21 Hz (correct) and 26-29 Hz (error), we found the sustained difference only before 650 ms. Our results suggest that SI is involved with the analysis of an input frequency and related to perception and decision at different latencies.

Metabolic clearance rate of testosterone in male epileptic patients on anti-convulsant therapy.

There are several reports which state that male epileptics on anti-convulsant therapy have reduced sexual activity. We and others have shown that, although total testosterone is raised, the free testosterone concentration is reduced in this patient population. This could be a result of an increased metabolic clearance rate (MCR) of testosterone, inadequate secretion of LH to stimulate testosterone synthesis or inappropriately low testosterone production by the Leydig cells. We have examined these possibilities by measuring the MCR of testosterone in 15 male epileptics on anti-convulsant therapy. In this group of patients, the mean LH (9.3 +/- 5.9 IU/l) and sex-hormone binding globulin (SHBG) (54.5 +/- 22.9 nmol/l) concentrations were significantly greater than those of five normal control subjects (4.7 +/- 1.11 IU/l and 26.0 +/- 7.0 nmol/l respectively). Mean total testosterone concentrations of the two groups were not significantly different but the mean percentage of free testosterone and free testosterone concentration were significantly lower in the patient population (2.06 +/- 0.43 vs 2.98 +/- 0.27 and 0.56 +/- 1.1 vs 0.79 +/- 0.07 pmol/l). The MCR of testosterone was significantly lower in the patients (773 +/- 322 vs 1354 +/- 443 l/day) and showed a positive correlation with the percentage of free testosterone. Therefore, our results suggest that the lowered free testosterone in male epileptics on anti-convulsant therapy is not due to an increased MCR of testosterone. The increased LH concentration suggests primary hypogonadism. This, in turn, could be responsible for low free testosterone levels in the presence of normal testosterone.

Stigma in patients with early epilepsy: a national longitudinal study.

Forty six cases of epilepsy were identified from the National Survey of Health and Development. An index of social visibility at school was constructed from teachers' reports of survey members' behaviour at 15 years of age. For the sample as a whole this index was significantly associated with poorer educational outcomes, after adjusting for social background and measured attainment, but was not associated with poor occupational achievement. However the index did not differentiate between epileptic and non-epileptic children. Although cases with epilepsy were shown to be more at risk of psychiatric disturbance, it is concluded that their lives were less disrupted than might have been expected, and that there is no evidence from this study that stigma affects the lives of those whose epilepsy was not complicated by other pathologies.

Impaired sensorimotor gating in patients with non-epileptic seizures.

The aim of the study was to identify possible disturbances of sensorimotor gating and habituation of the eye blink startle response, in patients with non-epileptic seizures (NES). Prepulse inhibition (PPI) of the startle reflex, as an operational measure of sensorimotor gating and habituation was studied in 21 patients with NES and in 22 healthy control subjects. Six NES patients were taking antiepileptic drugs at the time of testing. PPI was significantly impaired in the NES group compared to the control group, with deficits being greater in unmedicated patients. There was a trend for medicated NES patients to show higher PPI than unmedicated patients, but this was not significant. Habituation was intact in both medicated and unmedicated NES patients. It is proposed that deficits of information processing related to sensorimotor gating in patients with NES may be associated with abnormalities within the limbic system-basal ganglia circuitry which has been shown to be the substrate of 'gating' assessed by PPI. It was also found that NES patients had greater psychopathology than the control group when rated by the Traumatic Symptom Checklist (TSC-40). Overall, the anxiety subscale was the only element that was negatively correlated with PPI. It is suggested that anxiety may contribute to impairment of PPI in patients with NES.

Metabolic and EEG changes during transcendental meditation: an explanation.

Two experiments were conducted to measure the oxygen uptake (Experiment II) and the carbon dioxide production (Experiment I) during transcendental meditation. A control group of non-meditators and a few meditators listening to music was used for both experiments. In Experiment I, a controlled group of fasting meditators was also included. A drop in oxygen consumption and carbon dioxide production, found by previous authors during transcendental meditation, was confirmed. It was, however, possible to show that these drops were physiologically of small significance, and were of the magnitude to be expected from muscle relaxation. EEG recordings were taken during Experiment II in the meditating group. The EEG results showed transcendental meditation to be a method of holding the mediator's level of consciousness at stage 'onset' sleep. No evidence could be found to suggest that meditation produced a hypometabolic state beyond that produced by muscle relaxation and there was no evidence that the EEG changes were different from those observed in stage 'onset' sleep. No support was found for the idea that transcendental meditation is a fourth stage of consciousness.

Positron emission tomography in male violent offenders with schizophrenia.

The FDG PET brain scans from 31 offenders with schizophrenia and schizoaffective disorder from a maximum security mental hospital were compared with those of normal controls (N = 6) in terms of relative FDG uptake in a range of regions covering frontal and temporal regions. The patient sample was divided into those who had a history of repetitive violent offending (RVO, N = 17) and those without a repetitive violent history (NRVO, N = 14) according to the violence rating of their pre-admission convictions. Reduced FDG uptake was noted at both the right and left anterior inferior temporal (R and L AIT) regions in NRVOs but only at LAIT in RVOs. NRVOs had significantly lower FDG uptake at RAIT than RVOs. The findings suggest that metabolic changes at AIT may be related to different patterns of violent offending in patients with schizophrenia.

Patients' and referring doctors' perceptions of treatment on an in-patient neuropsychiatry/epilepsy unit: a study of three cohorts.

Three cohorts of patients, discharged within three, 12-month periods from a tertiary referral Neuropsychiatry/Epilepsy Unit, were asked whether they felt their condition had improved as a result of their admission, how they valued the admission and how easy they had found the admission to manage. They were also asked about their psychological and psychosocial state. For the first cohort a longer admission was more greatly valued and was associated with a better self-perceived outcome, and for the second cohort with the manageability of the admission. Replies to questionnaires sent to the referring doctors of two of the three cohorts of patients indicated that, in addition to their being satisfied with the service, there was a positive correlation between their ratings of patients' improvement and those ratings offered by the patients themselves. Issues relating to length and purpose of admissions, finances and the distribution of assessment and treatment of patients across different services are discussed in the light of the findings.

Are what people know about their epilepsy and what they want from an epilepsy service related?

This study set out to investigate the level of knowledge about epilepsy in general and in relation to the patients' own condition, in patients attending a tertiary referral epilepsy outpatient clinic. It also sought to investigate patient satisfaction with the service and whether knowledge acquired about epilepsy related to that satisfaction. Seventy out of 94 patients responded to the Epilepsy Knowledge Profile Questionnaires (general and personal knowledge of epilepsy) and a questionnaire assessing service satisfaction. Patients were found to know more about epilepsy in general than about their own condition. In particular some patients were unable to give accurate indications of their drug regimes. Over 91% were satisfied with the serviced they received but this bore no relation to information they had acquired or wanted about epilepsy. Multidisciplinary services were requested by a sizeable percentage of patients but especially access to a specialist nurse in epilepsy. The study highlights the need for clinicians to check patients' knowledge about their condition and for further work to clarify the source of patients' satisfaction with service delivery.

Petechial haemorrhage following a partial seizure with secondary generalization: atypical presentation and differential diagnosis.

A case is reported of a patient who had a respiratory arrest on a high dependency ward in a High Security Hospital with an unusual presentation. The patient had head and upper abdominal petechial haemorrhages with extensive conjunctival haemorrhaging. A considered antecedent for this potentially life-threatening presentation was strangulation. Analysis of all the available clinical information supports the hypothesis that he had a single tonic-clonic seizure with a focal-motor onset. This constitutes an unusual consequence of a partial seizure with secondary generalization.

Analysis of brain activity immediately before conscious teeth clenching using magnetoencephalographic method.

The reasons for unconscious teeth clenching have not been clarified. The long-term goal of our project was the elucidation of processing in the brain immediately before unconscious teeth clenching, in order to clarify its significance in humans. The objective of the present study was to establish a magnetoencephalographic (MEG) method of measuring brain activity immediately before clenching, and to clarify the time-course of brain activity immediately before conscious clenching. We measured the MEG signal in six subjects before, during and after clenching in a protocol that restricted head movement <5 mm. We derived tomographic estimates of brain activity for each time slice of data, as well as time courses for regional brain activations. Analysis of the tomographic images and time courses yielded statistical maps of activity in the motor, pre-motor and somatosensory cortices immediately before clenching in all subjects. Activations were found bilaterally, but with a strong unilateral bias in most subjects. Our results demonstrate that the MEG procedures, we have introduced are capable of measuring brain activity immediately before clenching, and indicate that analysis should begin from at least 200 ms before electromyogram onset.

Behavioural treatment of epilepsy.

There is abundant evidence of the close interrelation between the induction and inhibition of seizure activity and the patient's thoughts, feelings and behaviour. The detailed knowledge that we now have of the epileptic focus and the way that it is connected to the surrounding cerebral mechanisms, makes it possible for many patients with focal epilepsy to establish a significant degree of seizure control by altering their thinking and behaviour.

The relationship between mind, brain, and seizures.

The medical model of epilepsy suggests that seizures arise at random or in response to precise physiological events. Little weight is given to the part that ongoing brain activity may play in either precipitating or inhibiting seizures. In the focal epilepsies, the presence of damaged neurons that fire in the epileptic mode continuously and are called pacemaker cells has been demonstrated in both animal models and human epilepsy. If these pacemaker cells are firing all the time, why then do seizures arise only spasmodically? Behavior can be thought of as changes in the excitation and inhibition of populations of neurons. Therefore, it is likely that these excitatory and inhibitory waves will either increase or decrease the likelihood of seizures arising. The conditioning of the neurons to fire in volleys in a biofeedback paradigm, the conditioning of seizures in a classic Pavlovian sense, and the occurrence of seizures in response to behavioral changes has been shown in animal models of epilepsy and in humans. There is now evidence that children can both inhibit and generate their own seizures spontaneously. Many adult patients have behavioral strategies that they use either to inhibit or to stop the spreading seizures. In patients who have difficulties in coping with the stresses in their life, the voluntary generation of seizures may come to form a response to difficult situations. Thus, any complete epilepsy program must consider the patient, the behavior, and the relationship between seizures and behavior.

Antiepileptic drugs and their psychotropic effects.

Antiepileptic drugs (AEDs) are still the main treatment for epilepsy. The first drugs such as the bromides, phenobarbital (PB), and related barbituates were all found to be anticonvulsant by chance. They also all carried to some extent the disadvantages of slowing thinking and motor behavior. Bromides are now seldom used and (PB) is only used when other drugs fail, although it is an important drug in the third world because of its low cost. Carbamazepine (CBZ), valproate (VPA), and phenytoin (PHT) are the current first-line AEDs. All of these drugs vary in the extent of their effect on mood. These drugs have also all been used in the treatment of psychiatric disorders. CBZ has been used mainly as a mood normalizer and has had some success in treating hypermanic episodes. VPA has been used successfully in the treatment of cyclical psychoses, whereas PHT, although it had a vogue in the 1940s for the treatment of psychosis, is little used as a psychological treatment now.

Evoked and psychogenic epileptic seizures: II. Inhibition.

The inhibition of seizure activity by behavioural methods is becoming more popular. Lockhart's monkey model of focal epilepsy suggests a theoretical approach to behavioural seizure inhibition. Behaviour, by changing the pattern of excitation and inhibition surrounding a focus, is thus able to inhibit seizure activity. This article describes single case studies in which the behavioural methods of cued arousal, covert desensitization and relaxation have brought about a decrease in seizure frequency.

Evoked and psychogenic epileptic seizures. I. Precipitation.

The precipitation of seizures by external stimulation (evoked seizures) is well known. Less well known is the precipitation of seizures by a change in the patient's thinking or feelings. This artick uses Lockhart's monkey model of focal epilepsy to propose that there is a close relationship between seizures and ongoing brain activity. Thus, seizures precipitated by both voluntary and spontaneous changes in behaviour and thinking must commonly occur. Clinical examples of such seizure precipitation is described.

The aetiology of aggression in temporal-lobe epilepsy.

A retrospective case-note survey was carried out on 31 subjects admitted with temporal-lobe epilepsy to the Maudsley hospital from 1974-1983 inclusive. Fourteen aggressive subjects were compared with the non-aggressive patients on 95 organic, developmental, and social variables. Aggressive behaviour was associated with male sex, early onset of seizures, and a history of long-standing behavioural problems. Aggressive subjects had lower mean IQ scores and poorer occupational records than controls. No relationship was found between aggression and the presence of specific EEG or CAT scan findings, or a history of psychosis. The results demonstrate the complex interplay between organic and socially mediated factors underlying aggressive behaviour in temporal-lobe epilepsy.