Biomedical subjects

R E O'Carroll

Publications and source records attributed to R E O'Carroll.

At least 19 recordsLinked to original sources

PubMed2003

Dissociation of affective modulation of recollective and perceptual experience following amygdala damage.

It has been suggested that similar neural mechanisms may underlie the affective modulation of both recollective and perceptual experience. A case is reported of a patient who has bilateral amygdala damage and marked impairment in the perception of emotion, particularly fear. The patient DR and 10 healthy control subjects (matched for school leaving age, intelligence quotient, and non-emotional memory performance) were shown a series of slides accompanied by an emotionally arousing narrative. One week later DR and the controls were given a surprise memory test for this material. In addition, they completed a verbal memory test using emotionally arousing stimuli. Both DR and the healthy control subjects showed a normative pattern of enhanced memory for emotional material. On the basis of these results and the previously demonstrated impairment of perception of emotion in this patient, it is concluded that different neural mechanisms may underlie affective modulation of recollective and perceptual experience.

Affect↗

PubMed2003

Decision making in humans: the effect of manipulating the central noradrenergic system.

OBJECTIVES: Damasio has proposed an influential model of human decision making-the Somatic Marker Hypothesis (SMH), where he argues that somatic feedback to the brain influences decision making in humans. It is proposed that when choosing between options that differ in relative risk, a somatic marker (for example, a "gut feeling") feeds back to the brain and influences cognitive appraisal. This study tested the hypothesis that the noradrenergic system may play a part in this afferent feedback process. METHODS: Thirty healthy young adults were randomly allocated to receive placebo, 4 mg, or 8 mg reboxetine (a new selective noradrenergic reuptake inhibitor that acts to increase central noradrenergic activity). It is hypothesised that enhancement of central noradrenergic activity may amplify the effect of afferent feedback, and lead to altered decision making. All subjects completed the Iowa Gambling Task (IGT), a computerised card playing game where the player is instructed to try and win as much money as possible over 100 selections from one of four decks. RESULTS: There were no significant differences between the three groups in gambling task performance. CONCLUSION: This result suggests that central noradrenergic activity may not be critically involved in the afferent feedback mechanism that is central to the somatic marker hypothesis.

Adrenergic Uptake Inhibitors↗

PubMed2002

Assessing the emotional impact of cadaver dissection on medical students.

AIM: The study's first aim was to assess the emotional impact of cadaver dissection on first year medical students using the newly developed Appraisal of Life Events Scale (ALE). Its secondary aim was to evaluate the validity of the ALE by comparing it with the Impact of Events Scale (IOE). SETTING: Division of Biomedical Sciences, School of Biology, University of St. Andrews. SUBJECTS AND METHOD: Appraisal of Life Events and Impact of Events data were obtained from 114 UK medical students 4 weeks after their first cadaver dissecting class. Main outcome measures referred to the ALE and IOE scales. RESULTS: The students rated the experience as largely positive, registering significantly higher scores on the ALE challenge factor than on ALE threat or ALE loss. Significant correlations between ALE threat and loss scores and IOE intrusions and avoidance scores were noted. CONCLUSION: The results indicate that medical students do not report their first exposure to cadaver dissection as an aversive experience. Instead, as the ALE results confirm, they found it to be a positive and challenging life event. The ALE appears to be a useful instrument in assessing positive and negative emotional reactions to significant life events.

Adaptation, Psychological↗

PubMed2001

Psychological factors associated with delay in attending hospital following a myocardial infarction.

OBJECTIVE: There is wide variability in latency to attend hospital following a myocardial infarction (MI). The present study assessed possible psychological factors that may be implicated in delayed presentation. METHOD: Seventy-two patients who had experienced a confirmed MI were interviewed in hospital, 3-5 days post-MI. They completed a series of psychological measures of cardiac denial, cardiac threat, alexithymia, health locus of control, neuroticism and mood. RESULTS: Those patients who believed that they were having a heart attack sought help quicker than those who did not, and those who waited over 4 hours prior to seeking medical help had significantly lower scores on neuroticism, and higher scores on denial and health locus of control (chance). Confirmatory multiple regression analysis using an alternative estimate of delay in seeking help confirmed that health locus of control (chance) was the best predictor of delayed attendance. CONCLUSION: The present study confirms that the belief that one is having a MI is associated with prompt attendance, and additionally that the belief that health outcomes are largely due to chance factors is associated with delayed presentation following a MI. This delay could prove fatal. Modification of such beliefs may reduce response times and, thus, increase survival rates.

Denial, Psychological↗

PubMed2001

Decision making in patients with spinal cord damage: afferent feedback and the somatic marker hypothesis.

Damasio has proposed an influential model of human decision making - the somatic marker hypothesis (Damasio AR. Descates' Error. London: Papermac/Macmillan, 1994), where he argues that somatic feedback to the brain influences decision making in man. It is proposed that when choosing between options that differ in relative risk, a somatic marker (e.g. a 'gut feeling') feeds back to the brain and influences cognitive appraisal. In the present study patients who had suffered a complete tetraplegia at the level of the sixth cervical vertebra were compared with matched healthy control subjects. As the spinal injury group have reduced somatic/peripheral feedback via the spinal cord, it was predicted, based on the somatic marker hypothesis, that they may demonstrate riskier behaviour than controls. All subjects completed the Iowa Gambling Task, a computerised card playing game where the player is instructed to try and win as much money as possible over 100 selections from one of four decks. The rules are not disclosed in advance, and the player gradually 'learns' that two of the decks are 'high risk' and lead to significant financial losses. Healthy individuals have previously been shown to learn to avoid the risky decks, whereas patients with medial frontal lobe damage (Bechara A, Damasio AR, Damasio H, Anderson SW. Insensitivity to future consequences following damage to human prefrontal cortex. Cognition 1994;50:7-15) and those with peripheral neuropathy (Bechara A, Tranel D, Wilson J, Heberlein AS, Ross M, Damasio AR, 1998. Impaired decision-making in peripheral neuropathy. Society for Neuroscience Abstracts 24:1176) select an excessive number from the risky decks, and consequently lose money. In the present study there were no significant differences between the spinal sectioned and healthy control groups in either card selection strategy or net financial outcome. This result suggests that in terms of the somatic marker hypothesis, feedback to the brain from the periphery via the cranial vagus and other nerves and the hormonal route may be equally or more influential than afferent feedback transmitted via the spinal cord.

Adult↗

PubMed2000

Chronicity of memory impairment in long-term out-of-hospital cardiac arrest survivors.

As a result of out-of-hospital defibrillation initiatives, many cities have an increasing population of out-of-hospital cardiac arrest survivors. We previously identified that one third of these patients suffer memory problems in the months after resuscitation. The pattern of memory impairment (impaired recall memory and intact recognition memory) is suggestive of hippocampal damage. In this study we followed up ten subjects who had previously been found to have memory impairment after their cardiac arrest. To assess the chronicity of this memory impairment, we re-tested memory function approximately 3 years after the index events. These subjects were compared with age and sex matched control subjects with previous myocardial infarction and no cardiac arrest. Memory was assessed using the Rivermead Behavioural Memory test (RBMT). To further assess recall and recognition memory we used the Doors and People test (DPT), which is specifically designed to identify deficits in these functions. RBMT scores declined significantly in both groups compared with the original assessment 8 months after cardiac arrest, possibly an effect of ageing-control group: mean (S.D.) 22.2 (1. 4)-18.4 (2.9); cardiac arrest group: 16.1 (2.7)-14.6 (4.4). The inter-group difference in RBMT score remained significant (P=0.001). DPT scores were poor in the cardiac arrest group (mean (S.D.) total 5.8 (2.8)), compared with the control group (10.8 (3.4)) who scored normally. Both recall and recognition memory were poor in the cardiac arrest group. We conclude that the memory deficits that we previously observed in cardiac arrest victims are persistent. Both recall and recognition memory are affected, implying that non-selective brain injury may be the mechanism.

Aged↗

PubMed2000

The difference in patterns of motor and cognitive function in chronic fatigue syndrome and severe depressive illness.

BACKGROUND: Chronic fatigue syndrome (CFS) and major depressive disorder (MDD) share many symptoms and aetiological factors but may have different neurobiological underpinnings. We wished to determine the profile of the biological variables disturbed in CFS and MDD, and identify any critical factors that differentiate the disorders. METHODS: Thirty patients with CFS, 20 with MDD and 15 healthy controls matched group-wise for age and sex were recruited. Subjects were given a detailed battery of motor and cognitive tests, including measures of psychomotor speed, memory and maximal voluntary muscle contraction in both the morning and evening that were balanced to avoid order effects. RESULTS: CFS patients generally performed worse on cognitive tests than healthy controls, but better than patients with MDD. Both patient groups had markedly impaired motor function compared with healthy controls. MDD subjects showed a significantly greater diurnal improvement in maximal voluntary contraction than healthy controls. CONCLUSIONS: Patients with CFS and MDD show similarly substantial motor impairment, but cognitive deficits are generally more marked in MDD. Diurnal changes in some functions in MDD may differentiate the disorder from CFS.

Adult↗

PubMed2000

A comparison of the WHOQOL-100 and the WHOQOL-BREF in detecting change in quality of life following liver transplantation.

The World Health Organization has recently produced a generic quality of life measure--the WHOQOL-100, together with an abbreviated version, the WHOQOL-BREF. Preliminary data suggest that the WHOQOL BREF provides a valid and reliable alternative to the lengthier WHOQOL-100. In the present study, the sensitivity to change of both versions was tested pre- and 3 months post liver transplantation in fifty patients and also in twenty-one non-transplanted liver disease controls. Quality of Life domains on both measures were highly correlated, and were sensitive to change following transplant and remained stable on repeat assessment in non-transplanted control patients. However, the sensitivity to change was significantly reduced for the Social domain in the WHOQOL BREF. It is concluded that the WHO-QOL-BREF is a useful alternative to the WHOQOL-100 in evaluating quality of life improvement following major therapeutic interventions for Physical, Psychological and Environmental domains of life quality. However, researchers interested in measuring the Social aspects of life quality may be best advised to use the lengthier WHOQOL-100.

Female↗

PubMed2000

Memory impairment in out-of-hospital cardiac arrest survivors is associated with global reduction in brain volume, not focal hippocampal injury.

BACKGROUND AND PURPOSE: More than 30% of out-of-hospital cardiac arrest (OHCA) survivors suffer significant memory impairment. The hippocampus may be vulnerable to hypoxic injury during cardiac arrest. The purpose of this study was to determine whether selective hippocampal injury is the substrate for this memory impairment. METHODS: Seventeen OHCA survivors and 12 patients with uncomplicated myocardial infarction were studied. OHCA survivors were divided into those with impaired and intact memory. Memory was assessed by use of the Rivermead Behavioural Memory Test and Doors and People Test. MRI was used to determine intracranial, whole-brain, amygdala-hippocampal complex, and temporal lobe volumes. Brain structure was also examined by statistical parametric mapping. RESULTS: Left amygdala-hippocampal volume was reduced in memory-impaired OHCA victims compared with control subjects (mean 3. 93 cm(3) and 95% CI 3.50 to 4.36 cm(3) versus mean 4.65 cm(3) and 95% CI 4.37 to 4.93 cm(3); P=0.002). Left temporal lobe and whole-brain volumes were also reduced. There were no differences in amygdala-hippocampal volume indexed against ipsilateral temporal lobe volume. Significant correlations were observed between total brain volume and Rivermead Behavioural Memory Test (r=0.56, P<0.05) and Doors and People Test (r=0.67, P<0.01) scores in OHCA survivors. Both recall and recognition were compromised in memory-impaired subjects. Statistical parametric mapping did not detect focal brain abnormalities in these subjects. Global cerebral atrophy was confirmed by qualitative assessment. CONCLUSIONS: Memory impairment in OHCA survivors is associated with global cerebral atrophy, not selective hippocampal damage. Rehabilitation protocols need to account for the global nature of the brain injury.

Aged↗

PubMed1999

Errorless learning and the cognitive rehabilitation of memory-impaired schizophrenic patients.

BACKGROUND: In recent years, evidence has accumulated that a significant proportion of schizophrenic patients have severe memory impairment, which cannot be attributed to the effects of medication, chronicity or institutionalization. Our group has demonstrated that memory impairment is associated with poor psychosocial outcome and treatment resistance. Work on the classical amnesic syndrome has suggested that memory training is facilitated by adopting an 'errorless learning' approach, where subjects do not experience failure during learning. This is based on the theory that the preserved implicit memory of amnesic patients results in implicitly remembered incorrect responses interfering with target items, in the absence of a functioning explicit memory system to allow differentiation. METHOD: We compared three groups of subjects, memory-impaired schizophrenic patients, memory unimpaired schizophrenic patients and healthy controls. RESULTS: An errorless learning approach conferred a significant advantage on the memory-impaired schizophrenic group, bringing their performance up to the level of both control groups. In contrast, adopting a traditional trial and error, or errorful approach resulted in markedly impaired performance in the memory-impaired schizophrenic group only. CONCLUSIONS: We conclude that errorless learning approaches may be worthy of further evaluation in the cognitive rehabilitation of memory-impaired schizophrenic patients.

Adult↗

PubMed1999

Abnormal response to negative feedback in depression.

BACKGROUND: Recent studies have suggested that subjects with depression suffer a diagnosis-specific motivational deficit, characterized by an abnormal response to negative feedback that endures beyond clinical recovery. Furthermore, it has been suggested that negative feedback may motivate non-depressed controls, but not depressed patients, to improve their performance in neuropsychological tests. METHODS: We describe two studies. The first compared performance on the simultaneous and delayed match to sample (SDMS) task from the CANTAB neuropsychological test battery, in 20 patients with severe depression with 20 with acute schizophrenia, 40 with chronic schizophrenia and 40 healthy controls. The second examined the performance of depressed patients with diurnal variation in symptoms and cognitive function. RESULTS: All patients groups showed impairments on the simultaneous and delayed match to sample task compared to controls. Depressed patients did not show an abnormal response to negative feedback. Controls did not show a motivational effect of negative feedback. Depressed patients with diurnal variation showed no variation in their response to perceived failure. There was no evidence of abnormal response to negative feedback in any patient group using the 'runs test' or of a motivational effect in controls. Conditional probability analysis was not independent of the total number of errors made in the SDMS task. CONCLUSIONS: Further studies are suggested to examine whether an abnormal response to negative feedback characterizes particular subgroups of patients suffering from depression.

Acute Disease↗

PubMed1999

Stimulation of the noradrenergic system enhances and blockade reduces memory for emotional material in man.

BACKGROUND: It is clearly established that emotional events tend to be remembered particularly vividly. The neurobiological substrates of this phenomenon are poorly understood. Recently, the noradrenergic system has been implicated in that beta blockade has been shown to reduce significantly the delayed recall of emotional material with matched neutral material being unaffected. METHODS: In the present study, 36 healthy young adults were randomly allocated to receive either yohimbine, which stimulates central noradrenergic activity, metoprolol which blocks noradrenergic activity, or matched placebo. The three groups were well matched. All capsules were taken orally, prior to viewing a narrated 11 slide show described a boy being involved in an accident. RESULTS: Yohimbine significantly elevated, and metoprolol reduced mean heart rate during the slide show relative to placebo, thus confirming the efficacy of the pharmacological manipulation. One week later, in a surprise' test, memory for the slide show was tested. As predicted, yohimbine-treated subjects recalled significantly more and metoprolol subjects fewer slides relative to placebo. This result was confirmed via analysis of multiple-choice recognition memory scores. CONCLUSIONS: We conclude that stimulation of the noradrenergic system results in the enhancement and blockade in a reduction of recall and recognition of emotional material in man.

Adrenergic alpha-Agonists↗

PubMed1999

Evaluating methods for estimating premorbid intellectual ability in closed head injury.

OBJECTIVES: The present study examines the utility of three measures of premorbid intellectual functioning in closed head injury, the National adult reading test (NART), the Cambridge contextual reading test (CCRT), and the spot the word test (STW). METHODS: In the first experiment, a group of 25 patients with closed head injury were compared with 50 healthy controls and 20 orthopaedic trauma controls. In the second experiment, the strength of correlation between the premorbid measures and current intellectual level were assessed in 114 healthy adults. RESULTS: The head injured group performed significantly more poorly than both control groups on measures of current intellectual ability. However, no significant differences emerged between the groups on any of the premorbid measures. In the large control sample, both the NART and the CCRT accounted for about 50% of the variance in current verbal intelligence. However, by contrast, the STW only accounted for 29% of the variability in verbal intelligence. Adding demographic variables to the prediction of current intellectual level increased the amount of variance explained to 60% for the NART, 62% for the CCRT, but only 41% for the STW. CONCLUSION: The results provide supportive evidence for the use of the CCRT and NART in estimating premorbid intellectual functioning in patients who have sustained closed head injuries, but suggest caution when employing the STW.

Adult↗

PubMed1999

Memory for emotional material: a comparison of central versus peripheral beta blockade.

The connection between affect and memory is poorly understood. A possible psychopharmacological linking mechanism is the sympathetic arousal that occurs in response to threatening or emotive material. Cahill et al. (1994) reported that a single administration of 40 mg propranolol hydrochloride, a non-selective beta-adrenergic blocker, to healthy young adults significantly reduced delayed recall of emotive material, with recall of matched neutral material unaffected. This study differed importantly from the original Cahill et al. (1994) procedure in that only the emotionally arousing narrative was employed. Using the same slide presentation as Cahill et al. (1994), an experiment was carried out in order to determine whether beta-adrenergic blockade significantly reduces recall of emotive material via a central or peripheral mode of action. Thirty-six healthy young adults were recruited as subjects. Subjects were randomly allocated to three groups: (a) placebo (b) 40 mg propranolol hydrochloride (a beta blocker which readily crosses the blood brain barrier) and (c) 40 mg nadolol (a beta blocker which does not cross the blood-brain barrier). The three groups were matched for age, sex, intelligence, personality factors, and general memory functioning. Subjects viewed a series of 11 slides accompanied by a narrative, divisible into three phases. The emotionally arousing component of the narrative was introduced during phase II. Both central and peripheral beta blockade produced the expected effects on the sympathetic nervous system, as demonstrated by reliable reductions in systolic and diastolic blood pressure. In a surprise memory test 1 week later, subjects were asked to recall as much as possible of the story and slides, and also completed a forced choice recognition memory test. All three groups showed heightened recall and recognition for the central (emotive) section of the story. There was no differential effect of beta blockade (either central or peripheral) relative to placebo. Beta blockade markedly reduced systolic and diastolic blood pressure, but resulted in no significant effect on memory for both emotional and neutral material.

Adrenergic beta-Antagonists↗

PubMed1999

Reduced in vivo binding to the serotonin transporter in the cerebral cortex of MDMA ('ecstasy') users.

BACKGROUND: The use of MDMA ('ecstasy') is common among young people in Western countries. Animal models of MDMA toxicity suggest a loss of serotonergic neurons, and potentially implicate in the development of significant psychiatric morbidity in humans. AIMS: To test whether long-term use of MDMA can produce abnormalities in cerebral serotonin, but not dopamine, transporter binding measured by single photon emission computed tomography (SPECT). METHOD: Ten male regular ecstasy users and 10 well-matched controls recruited from the same community sources participated in SPECT with the serotonin transporter (SERT) ligand [123I] beta-CIT. Dopamine transporter binding was determined from scans acquired 23 hours after injection of the tracer. RESULTS: Ecstasy users showed a cortical reduction of SERT binding, particularly prominent in primary sensory-motor cortex, with normal dopamine transporter binding in lenticular nuclei. CONCLUSIONS: This cross-sectional association study provides suggestive evidence for specific, at least temporary, serotonergic neurotoxicity of MDMA in humans.

Adolescent↗

PubMed1999

Follow-up study of depression in the elderly. Clinical and SPECT data.

BACKGROUND: Imaging studies in depression of the elderly are often small and highly selective. AIMS: To investigate a large group of elderly depressed patients in order to assess changes in clinical, imaging and neuropsychological variables at follow-up. METHOD: Patients (n = 175, age range 65-91 years) with clinical depression were identified from consecutive local referrals. Clinical interviews, neuropsychological tests and SPECT scans were carried out at referral and at two-year follow-up. RESULTS: Of 84 re-examined patients, 46.5% were well, 9.5% were ill, 33% partially recovered and 11% had developed dementia. Duration of illness before index assessment was the only factor to predict outcome. Thirty-nine patients could be scanned and followed up. There were no differences between patients with good or poor depressive outcome on SPECT. Ten clinically improved patients could be re-examined with SPECT. There were relative increases in right cingulate gyrus and right cerebellum at follow-up. CONCLUSIONS: The patients group was comparable with other studies showing high levels of residual depressive symptoms. Activity changes in limbic cortex are implicated in depression of old age.

Aged↗

PubMed1999

Altered cerebral perfusion measured by SPECT in relatives of patients with schizophrenia. Correlations with memory and P300.

BACKGROUND: Genetic studies in schizophrenia are hampered by the complex heterogeneous clinical phenotype. Biological variables identified as trait markers of risk could clarify the mode of inheritance, define clinical subgroups and provide clues about aetiology. AIMS: To use single photon emission computed tomography (SPECT) to compare brain perfusion maps in patients with schizophrenia (n = 19), their asymptomatic 'high-risk' relatives (n = 36) and control subjects (n = 34) and to examine the relationships between imaging, memory and P300 event-related potential. METHOD: SPECT, memory tests and P300 recording were carried out. RESULTS: In the patients with schizophrenia and their relatives, perfusion was reduced in left inferior prefrontal and anterior cingulate cortex and increased bilaterally in a subcortical region. Perfusion significantly correlated with verbal memory and P300 amplitude in left inferior prefrontal cortex and with P300 latency in anterior cingulate cortex. CONCLUSIONS: Medication- and symptom-free relatives had altered regional perfusion intermediate between subjects with schizophrenia and controls. Impaired perfusion, verbal memory and P300 appear to be related traits associated with an increased risk of illness.

Adult↗

PubMed1999

Variceal haemorrhage and post-traumatic stress disorder.

OBJECTIVE: Post-traumatic Stress Disorder (PTSD) is thought to be relatively common following extremely distressing life-threatening events. Patients with liver cirrhosis can experience severe brisk variceal haemorrhage during which they vomit litres of blood and may exsanguinate. We predicted that a significant proportion of survivors would suffer from PTSD. DESIGN: PTSD assessment of 30 patients who had a haematemesis of more than four units of blood secondary to variceal bleeding and were fully conscious at the time of the bleed. METHOD: Structured Clinical Diagnostic Interview (SCID-DSM-III-R) and self-report measures. RESULTS: Most found the experience distressing, but only 1 out of 30 patients fulfilled DSM-III-R diagnostic criteria for PTSD. CONCLUSIONS: PTSD in a sample of patients who survived life-threatening variceal haemorrhage is much rarer than might reasonably have been anticipated. Possible reasons for this low prevalence of PTSD are discussed.

Attitude to Death↗