Neuropsychological Test Performance In Patients Research Articles

Research Review: Neuropsychological functioning in young anorexia nervosa: A meta-analysis.

Cognitive inflexibility and compulsive behaviours are commonly observed in patients with anorexia nervosa (AN) and are often considered to be caused by impairments in executive functioning and visuospatial processing. Despite an increasing number of young individuals presenting with AN, there is a lack of meta-analytic evidence on the neuropsychological functioning in this population. Our primary aim was to review and synthesize the differences in neuropsychological test performance between young people with AN and healthy controls, and to explore potential moderators. A database search following PRISMA guidelines of MEDLINE, PsycINFO, ISI Web of Science and Epistemonikos was conducted. Hedges' g served as an effect size indicating the standardized mean differences. We utilized mixed-effects meta-regression and machine learning meta-analyses to identify relevant moderators. Sixteen studies met the inclusion criteria with a total of 1333 participants (665 with AN) and 59 effect sizes. Random-effects meta-analyses demonstrated a small and insignificant difference between young individuals with AN and controls ( = -0.144, 95% CI [-0.328, 0.041]) in overall neuropsychological functioning. However, the difference was significant for the cognitive domains of memory, working memory and visuospatial abilities. Moderator and machine-learning analyses revealed a stronger negative effect in older participants and moderator effects of country and assessment quality. Our findings highlight the significant impact of age on neuropsychological test performance in patients with AN. There is a need for a more widespread inclusion of potentially confounding variables in primary studies as well as instruments specifically targeted at younger populations.

Quantified MRI and cognition in TBI with diffuse and focal damage

In patients with chronic-phase traumatic brain injury (TBI), structural MRI is readily attainable and provides rich anatomical information, yet the relationship between whole-brain structural MRI measures and neurocognitive outcome is relatively unexplored and can be complicated by the presence of combined focal and diffuse injury. In this study, sixty-three patients spanning the full range of TBI severity received high-resolution structural MRI concurrent with neuropsychological testing. Multivariate statistical analysis assessed covariance patterns between volumes of grey matter, white matter, and sulcal/subdural and ventricular CSF across 38 brain regions and neuropsychological test performance. Patients with diffuse and diffuse + focal injury were analyzed both separately and together. Tests of speeded attention, working memory, and verbal learning and memory robustly covaried with a distributed pattern of volume loss over temporal, ventromedial prefrontal, right parietal regions, and cingulate regions. This pattern was modulated by the presence of large focal lesions, but held even when analyses were restricted to those with diffuse injury. Effects were most consistently observed within grey matter. Relative to regional brain volumetric data, clinically defined injury severity (depth of coma at time of injury) showed only weak relation to neuropsychological outcome. The results showed that neuropsychological test performance in patients with TBI is related to a distributed pattern of volume loss in regions mediating mnemonic and attentional processing. This relationship holds for patients with and without focal lesions, indicating that diffuse injury alone is sufficient to cause significant neuropsychological disability in relation to regional volume loss. Quantified structural brain imaging data provides a highly sensitive index of brain integrity that is related to cognitive functioning in chronic phase TBI.

Association between fully automated MRI-based volumetry of different brain regions and neuropsychological test performance in patients with amnestic mild cognitive impairment and Alzheimer’s disease

Fully automated magnetic resonance imaging (MRI)-based volumetry may serve as biomarker for the diagnosis in patients with mild cognitive impairment (MCI) or dementia. We aimed at investigating the relation between fully automated MRI-based volumetric measures and neuropsychological test performance in amnestic MCI and patients with mild dementia due to Alzheimer's disease (AD) in a cross-sectional and longitudinal study. In order to assess a possible prognostic value of fully automated MRI-based volumetry for future cognitive performance, the rate of change of neuropsychological test performance over time was also tested for its correlation with fully automated MRI-based volumetry at baseline. In 50 subjects, 18 with amnestic MCI, 21 with mild AD, and 11 controls, neuropsychological testing and T1-weighted MRI were performed at baseline and at a mean follow-up interval of 2.1 ± 0.5 years (n = 19). Fully automated MRI volumetry of the grey matter volume (GMV) was performed using a combined stereotactic normalisation and segmentation approach as provided by SPM8 and a set of pre-defined binary lobe masks. Left and right hippocampus masks were derived from probabilistic cytoarchitectonic maps. Volumes of the inner and outer liquor space were also determined automatically from the MRI. Pearson's test was used for the correlation analyses. Left hippocampal GMV was significantly correlated with performance in memory tasks, and left temporal GMV was related to performance in language tasks. Bilateral frontal, parietal and occipital GMVs were correlated to performance in neuropsychological tests comprising multiple domains. Rate of GMV change in the left hippocampus was correlated with decline of performance in the Boston Naming Test (BNT), Mini-Mental Status Examination, and trail making test B (TMT-B). The decrease of BNT and TMT-A performance over time correlated with the loss of grey matter in multiple brain regions. We conclude that fully automated MRI-based volumetry allows detection of regional grey matter volume loss that correlates with neuropsychological performance in patients with amnestic MCI or mild AD. Because of the high level of automation, MRI-based volumetry may easily be integrated into clinical routine to complement the current diagnostic procedure.

The effect of seasons and seasonal variation on neuropsychological test performance in patients with bipolar I disorder and their first-degree relatives

Background Bipolar disorder (BD) patients have cognitive deficits that may remain in the euthymic phase. Similar although milder cognitive deficits may be found in their first-degree relatives. We wanted to analyze whether the self-report of seasonality, the season when individuals were tested or the circadian preference influences the neuropsychological test performance measured in the familial BD, type I, patients and their healthy first-degree relatives. Method A structured diagnostic interview (SCID) and neuropsychological test battery were administered to 32 familial BD type I patients, 40 of their unaffected first-degree relatives and 50 controls, all from population-based samples. BD patients and their relatives filled in the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Horne–Östberg Morningness–Eveningness Questionnaire (MEQ). Results Individuals, who reported that seasonal variation was a problem, scored worse on the measures of visuoconstructional functions, visuospatial reasoning, auditory attention and working memory, and verbal memory than those with no seasonal variation. The season when tested had an influence on test performance. Individuals from the families that were tested in spring, summer and autumn scored better than those tested in winter on the measures of visual and verbal attention, working memory, verbal ability, verbal fluency, and executive functioning. Among the controls there was no difference in the test scores from season to season. The circadian preference had no effect on test performance. Limitations Only relatives, not BD patients were tested in winter. Conclusion Seasonal variation in mood and behavior as a problem in patients and their first-degree relatives influences negatively the neuropsychological test performance. In addition, among the patients and first-degree relatives the neuropsychological test performance in winter may be worse than in other seasons.

Carotid artery intima-media thickness and cognition in cardiovascular disease

Background Increased carotid artery intima-media thickness (IMT) is a non-invasive marker of systemic arterial disease. Increased IMT has been associated with atherosclerosis, abnormal arterial mechanics, myocardial infarction, and stroke. Given evidence of a relationship between cardiovascular health and attention-executive-psychomotor functioning, the purpose of this study was to examine IMT in relation to neuropsychological test performance in patients with a variety of cardiovascular diagnoses. Methods One hundred and nine participants, ages 55 to 85, underwent neuropsychological assessment and B-mode ultrasound of the left common carotid artery. IMT was calculated using an automated algorithm based on a validated edge-detection technique. The relationship between IMT and measures of language, memory, visual–spatial abilities and attention-executive-psychomotor functioning was modeled using hierarchical linear regression analyses adjusted for age, education, sex, cardiovascular risk, current systolic blood pressure, and history of coronary artery disease (CAD). Results Increased IMT was associated with significantly lower performance in the attention-executive-psychomotor domain (IMT beta = − 0.26, p < .01), independent of age, education, sex, cardiovascular risk, current systolic blood pressure, and CAD ( F(10,100) = 3.61, p < .001). IMT was not significantly related to language, memory, or visual–spatial abilities. Conclusions Our findings suggest that, in patients with cardiovascular disease, IMT may be associated with the integrity of frontal subcortical networks responsible for attention-executive-psychomotor performance. Future studies are needed to clarify the mechanisms by which IMT affects cognition and examine potential interactions between increased IMT and other measures of cardiovascular health such as blood pressure variability, cardiac systolic performance, and systemic perfusion.

Neuropsychological test performance in patients co-infected with hepatitis C virus and HIV

To determine the effect of co-infection on neuropsychological performance in relatively healthy hepatitis C virus (HCV)-alone patients when compared with HCV/HIV-co-infected patients. To test whether the burden of co-infection with HCV and HIV on the central nervous system results in increased cognitive deficits, we tested 47 HCV-alone and 29 HCV/HIV-co-infected patients on a neuropsychological screening battery of tests of attention, concentration and psychomotor speed. The neuropsychological test performance of HCV-alone and HCV/HIV-co-infected patients was compared with normative samples. The test performance between HCV-alone and HCV/HIV-co-infected patients was also assessed. Patients with chronic liver disease were divided on the basis of disease severity as determined by fibrosis stage, according to the METAVIR system. Neuropsychological test performance was correlated with fibrosis stage. As previously reported, HCV patients independent of co-infection status demonstrated deficits on neuropsychological measures of attention, concentration and psychomotor speed. No significant differences were found between patients with HCV-alone and HCV/HIV-co-infected patients on the neuropsychological measures. There was a relationship between neuropsychological test performance and fibrosis stage. Relatively healthy patients with HCV (either alone or when co-infected with HIV) may have deficits in the domains of attention, concentration and psychomotor speed. In this study no significant differences were found between patients with HCV alone and HCV/HIV-co-infected patients on neuropsychological measures, but as previously demonstrated, greater fibrosis was associated with poorer performance.

Invited Commentary

Bossema et al have presented a study of cognitive function in patients undergoing carotid endarterectomy. The neuropsychologic tests may not be familiar to vascular surgeons, although this topic has been addressed in several recent articles.1Antonelli Incalzi R. Gemma A. Landi F. Pagano F. Capparella O. Snider F. et al.Neuropsychologic effects of carotid endarterectomy.J Clin Exp Neuropsychol. 1997; 19: 785-794Crossref PubMed Scopus (27) Google Scholar, 2Ucles P. Almarcegui C. Lorente S. Romero F. Marco M. Evaluation of cerebral function after carotid endarterectomy.J Clin Neurophysiol. 1997; 14: 242-249Crossref PubMed Scopus (14) Google Scholar, 3Irvine C.D. Gardner F.V. Davies A.H. Lamont P.M. Cognitive testing in patients undergoing carotid endarterectomy.Eur J Vasc Endovasc Surg. 1998; 15: 195-204Abstract Full Text PDF PubMed Scopus (53) Google Scholar, 4Aharon-Peretz J. Tomer R. Gabrieli I. Aharonov D. Nitecki S. Hoffman A. Cognitive performance following endarterectomy in asymptomatic severe carotid stenosis.Eur J Neurol. 2003; 10: 525-528Crossref PubMed Scopus (27) Google Scholar, 5Fearn S.J. Hutchinson S. Riding G. Hill-Wilson G. Wesnes K. McCollum C.N. Carotid endarterectomy improves cognitive function in patients with exhausted cerebrovascular reserve.Eur J Vasc Endovasc Surg. 2003; 26: 529-536Abstract Full Text Full Text PDF PubMed Scopus (63) Google Scholar, 6Kishikawa K. Kamouchi M. Okada Y. Inoue T. Ibayashi S. Iida M. Effects of carotid endarterectomy on cerebral blood flow and neuropsychological test performance in patients with high-grade carotid stenosis.J Neurol Sci. 2003; 213: 19-24Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar, 7Pearson S. Maddern G. Fitridge R. Cognitive performance in patients after carotid endarterectomy.J Vasc Surg. 2003; 38: 1248-1253Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar Comparison with a group without known vascular disease and a group undergoing surgery for lower extremity arteriosclerosis is novel. Experimental groups were comparable for other than the usual predictors of atherosclerosis. Control subjects did not undergo repeat testing, which would have allowed better assessment of the training effect addressed in the surgical groups. However, the study provides some fascinating insights into possible cognitive dysfunction in subjects with both carotid and lower-extremity atherosclerosis. Subjects with overt stroke were excluded, implying no evidence of cerebral dysfunction on conventional neurologic examination. Nevertheless, when compared using neuropsychologic tests, subjects with carotid or lower-extremity atherosclerosis scored less well than healthy controls, suggesting the presence of some systemic vascular disease. This also speaks to the crudeness of the standard neurologic examination as a test for higher cerebral functions. The investigators showed no cognitive improvement with carotid endarterectomy. Pearson et al7Pearson S. Maddern G. Fitridge R. Cognitive performance in patients after carotid endarterectomy.J Vasc Surg. 2003; 38: 1248-1253Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar made similar observations in this journal. This may at first seem disappointing, but is consistent with the concept that carotid endarterectomy is prophylactic. This conflicts with the results of some previous studies,1Antonelli Incalzi R. Gemma A. Landi F. Pagano F. Capparella O. Snider F. et al.Neuropsychologic effects of carotid endarterectomy.J Clin Exp Neuropsychol. 1997; 19: 785-794Crossref PubMed Scopus (27) Google Scholar, 5Fearn S.J. Hutchinson S. Riding G. Hill-Wilson G. Wesnes K. McCollum C.N. Carotid endarterectomy improves cognitive function in patients with exhausted cerebrovascular reserve.Eur J Vasc Endovasc Surg. 2003; 26: 529-536Abstract Full Text Full Text PDF PubMed Scopus (63) Google Scholar, 6Kishikawa K. Kamouchi M. Okada Y. Inoue T. Ibayashi S. Iida M. Effects of carotid endarterectomy on cerebral blood flow and neuropsychological test performance in patients with high-grade carotid stenosis.J Neurol Sci. 2003; 213: 19-24Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar but there may be methodologic problems with some of those studies.3Irvine C.D. Gardner F.V. Davies A.H. Lamont P.M. Cognitive testing in patients undergoing carotid endarterectomy.Eur J Vasc Endovasc Surg. 1998; 15: 195-204Abstract Full Text PDF PubMed Scopus (53) Google Scholar We wonder what might have been observed had cognitive testing been performed in trials such as NASCET, ECST, and ACAS.8North American Symptomatic Carotid Endarterectomy Trial CollaboratorsBeneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis.N Engl J Med. 1991; 325: 445-453Crossref PubMed Scopus (7402) Google Scholar, 9European Carotid Surgery Trialists’ Collaborative GroupMRC European Carotid Surgery Trial interim results for symptomatic patients with severe (70–99%) or with mild (0–29%) carotid stenosis.Lancet. 1991; 337: 1235-1243Abstract PubMed Scopus (2977) Google Scholar, 10Executive Committee for the Asymptomatic Carotid Atherosclerosis StudyEndarterectomy for asymptomatic carotid artery stenosis.JAMA. 1995; 273: 1421-1428Crossref PubMed Scopus (4853) Google Scholar Would the status of nonsurgical subjects have deteriorated as assessed by cognitive testing? Would the number of nonsurgical subjects whose status deteriorated have exceeded the number identified on conventional examination as having had a stroke? Future trials in carotid intervention, including carotid angioplasty, should build on the observations of Bossema et al and should consider designs that allow serial neuropsychologic testing in all treatment arms, including control groups without known vascular disease.

Effects of carotid endarterectomy on cerebral blood flow and neuropsychological test performance in patients with high-grade carotid stenosis

We examined the changes in cognitive function following carotid endarterectomy (CEA) in relation to the cerebral blood flow (CBF) in patients with high-grade carotid stenosis. The subjects consisted of 23 patients who underwent CEA and 17 controls matched by age and education. Single photon emission computed tomography (SPECT) and neuropsychological tests were performed 2 weeks before and 4 weeks after CEA in all patients. The preoperative CBF tests revealed a decreased vasodilatory reserve in the ipsilateral cerebral hemisphere in nine patients, which was increased after CEA. In these patients, the grade of carotid stenosis was significantly higher than in those with a normal perfusion reserve (90.2±8.1% vs. 78.6±11.3%, respectively, p<0.05). In the patient group, the postoperative scores (27.2±2.9) of the mini-mental state examination (MMSE) improved significantly over the preoperative ones (26.1±3.2, p<0.05). Moreover, the scores in the block-design test after CEA (86.8±19.8) were significantly higher than those before the operation (81.8±22.3, p<0.01). The error score in immediate retention improved from 9.0±3.1 to 7.7±4.0 following CEA ( p<0.05). In the control group, none of the test scores showed significant improvement between the first and second tests. In the patients with an impaired vasodilatory reserve, the mean score of the block-design test significantly improved from 65.6±22.1 to 74.0±19.2 after CEA compared with those in patients without impairment ( p<0.05). High-grade carotid stenosis was thus concluded to cause cognitive impairment due to cerebral hemodynamic failure, which is presumably reversed by CEA.

A controlled prospective study of neuropsychological dysfunction following carotid endarterectomy.

Although subtle cognitive injury as revealed by neuropsychological testing occurs in a substantial number of patients following carotid endarterectomy (CEA), there is controversy about whether this finding is a result of the surgery or the anesthesia. To examine the changes in neuropsychological test performance in patients following CEA vs a control group of patients older than 60 years following spine surgery, so as to determine whether neuropsychological dysfunction after CEA is a result of surgery or anesthesia. Patients undergoing CEA (n = 80) and lumbar spine surgery (n = 25) were assessed with a battery of neuropsychological tests preoperatively and on postoperative days 1 and 30. The neuropsychological performance of patients in the control group was used to normalize performance for patients in the CEA group, by calculating z scores using the mean and SD of the change scores in the control group. Significant cognitive dysfunction was defined as performance that exceeded 2 SDs above the mean performance of patients in the control group. Postoperative days 1 and 30 total deficit scores were significantly worse in the CEA group compared with the controls. When individual test results were examined, the CEA group performed significantly worse than the controls on the Rey Complex Figure test and Halstead-Reitan Trails B on day 1, and on the Rey Complex Figure on day 30. Overall, cognitive dysfunction was seen in 22 patients (28%) in the CEA group on day 1 and in 11 (23%) of 48 patients on day 30. Subtle cognitive decline following CEA occurs and persists for at least several weeks after surgery. This decline was absent in a control group.

Efficacy of L-Carnitine in Reducing Hyperammonaemia and Improving Neuropsychological Test Performance in Patients with Hepatic Cirrhosis

To determine the efficacy of L-carnitine in reducing hyperammonaemia and improving neuropsychological performance in patients with hepatic cirrhosis and subclinical hepatic encephalopathy (SHE). Randomised, parallel group, controlled trial. The study enrolled 31 patients with hepatic cirrhosis resulting from hepatitis C and/or hepatitis B, alcohol abuse and other causes. Patients randomised to active treatment, received oral L-carnitine 6 g/day in two divided doses for 4 weeks. Diagnosis of SHE was based on psychometric tests (subtests of the Wechsler Adult Intelligence Scale-Revised and the Halstead-Reitan Neuropsychological Test Battery) carried out at beginning and end of study. Serum ammonia levels were measured before treatment and weekly thereafter. A total of 27 patients completed the study. Sixteen patients received L-carnitine and 11 served as controls (no treatment). L-carnitine caused rapid and significant reductions in ammonia levels, sustained over the 4-week treatment period (mean reductions 60.1 and 1.4 (μmol/L in the treated and control groups, respectively). Normal ammonia levels were attained in 14 of 16 patients receiving L-carnitine. Based on psychometric test results, seven patients (43.7%) in the L-carnitine group and five (45.5%) in the control group had SHE at baseline. L-carnitine treatment for 4 weeks caused a net overall improvement in psychometric test results compared with controls. No clinically significant adverse events were reported and all patients receiving L-carnitine reported subjective improvements in their condition. RESULTS of this preliminary study indicate that L-carnitine reduces hyperammonaemia and improves the clinical symptoms of SHE in patients with hepatic cirrhosis.

Effect of clozapine on neuropsychological test performance in patients with schizophrenia

Effect of clozapine on neuropsychological test performance in patients with schizophrenia

Common sense, insight, and neuropsychological test performance in patients with schizophrenia

Common sense, insight, and neuropsychological test performance in patients with schizophrenia

Cortical gray matter volume deficit is present in first episode schizophrenics

In patients with chronic-phase traumatic brain injury (TBI), structural MRI is readily attainable and provides rich anatomical information, yet the relationship between whole-brain structural MRI measures and neurocognitive outcome is relatively unexplored and can be complicated by the presence of combined focal and diffuse injury. In this study, sixty-three patients spanning the full range of TBI severity received high-resolution structural MRI concurrent with neuropsychological testing. Multivariate statistical analysis assessed covariance patterns between volumes of grey matter, white matter, and sulcal/subdural and ventricular CSF across 38 brain regions and neuropsychological test performance. Patients with diffuse and diffuse + focal injury were analyzed both separately and together. Tests of speeded attention, working memory, and verbal learning and memory robustly covaried with a distributed pattern of volume loss over temporal, ventromedial prefrontal, right parietal regions, and cingulate regions. This pattern was modulated by the presence of large focal lesions, but held even when analyses were restricted to those with diffuse injury. Effects were most consistently observed within grey matter. Relative to regional brain volumetric data, clinically defined injury severity (depth of coma at time of injury) showed only weak relation to neuropsychological outcome. The results showed that neuropsychological test performance in patients with TBI is related to a distributed pattern of volume loss in regions mediating mnemonic and attentional processing. This relationship holds for patients with and without focal lesions, indicating that diffuse injury alone is sufficient to cause significant neuropsychological disability in relation to regional volume loss. Quantified structural brain imaging data provides a highly sensitive index of brain integrity that is related to cognitive functioning in chronic phase TBI.

Neuropsychological test performance in patients with dominantly inherited spinocerebellar ataxia

To determine whether the cognitive status of patients with dominantly inherited spinocerebellar ataxia (DSCA) might be related to neurologic severity, we administered a comprehensive neuropsychological test battery to 43 patients with DSCA, ranging in ataxia severity from mild to end-stage. As compared with the controls, the mildly ataxic patients scored normally or close to normal as a group on all of the neuropsychological tests. In contrast, approximately one-half of the moderately and all of the severely ataxic patients showed poor performance, independent of age, Hamilton Rating Scale for Depression score, or education, on the Wisconsin Card Sorting Test, suggesting impaired executive system function. In addition, a subgroup of these patients had a neuropsychological profile suggestive of mild generalized cognitive impairment. We conclude that DSCA is not a homogeneous group of disorders with respect to cognitive status and that the neurologic severity of the disorder is a major factor. Impaired executive system function could be explained by damage to olivopontocerebellar system control over cerebral cortical function or to damage to other neuronal systems (especially cholinergic) that degenerate in parallel with the olivopontocerebellar system.

Brain metabolism in Alzheimer's dementia: studies of 11C-deoxyglucose accumulation, CSF monoamine metabolites and neuropsychological test performance in patients and healthy subjects.

Thirteen patients with dementia of Alzheimer type and nine age-matched control subjects were examined by a battery of neuropsychological tests and by positron emission tomography (PET) with 11C-deoxyglucose as a tracer for regional glucose metabolism in the brain. Concentrations of the monoamine metabolites HVA, MHPG and 5-HIAA were determined in the CSF from patients and controls. In the patients there was a diminished glucose metabolism in posterior parietal and superior temporal cortex areas to 60% of control levels. Other cortical areas showed similar changes, whereas the pre- and postcentral area, the cerebellum, the hippocampus and the basal ganglia showed less or no change. The decline in cortical metabolism in the patients was symmetrical but the variation in the left/right ratio was greater than in the controls. The CSF levels of monoamine metabolites did not differ between patients and controls. High levels of the metabolites were associated with low rates of glucose metabolism, possibly due to inhibitory influences of monoaminergic pathways upon cortical and subcortical neurons. The rate of glucose metabolism correlated positively with the neuropsychological test performance in both patients and controls. Verbal and memory performances were associated with greater left hemisphere metabolism in the patients, but not in the controls, whereas non-verbal abilities tended to be associated with right hemisphere metabolic dominance.

Brain metabolism in alzheimer's dementia — studies of 11C-deoxyglucose accumulation and neuropsychological test performance in patients and healthy control : H. Nyman, H. Nybäck, G. Blomqvist, I. Sjögren, S. Stone-Elander. Departments of Psychiatry and Psychology, Neuroradiology, clinical Neurophysiology and Pharmacy, Karolinska Institute and Hospital, Stockholm, Sweden.

Brain metabolism in alzheimer's dementia — studies of 11C-deoxyglucose accumulation and neuropsychological test performance in patients and healthy control : H. Nyman, H. Nybäck, G. Blomqvist, I. Sjögren, S. Stone-Elander. Departments of Psychiatry and Psychology, Neuroradiology, clinical Neurophysiology and Pharmacy, Karolinska Institute and Hospital, Stockholm, Sweden.