Search results
Found 18567 matches for
Left dorso-lateral repetitive transcranial magnetic stimulation affects cortical excitability and functional connectivity, but does not impair cognition in major depression.
PURPOSE: Transcranial magnetic stimulation (TMS) has been used for over a decade to investigate cortical function. More recently, it has been employed to treat conditions such as major depression. This study was designed to explore the effects of differential treatment parameters, such as stimulation frequency. In addition, the data were examined to determine whether a change in connectivity occurred following TMS. METHOD: Fifteen patients with major depression were entered into a combined imaging and treatment experiment with single photon emission computed tomography (SPECT) and repetitive transcranial magnetic stimulation (rTMS) over left dorso-lateral prefrontal cortex (DLPFC). Brain perfusion during a verbal fluency task was compared between pre- and poststimulation conditions. Patients were then treated with 80% of motor threshold for a total of 10 days, using 5000 stimuli at 5, 10 or 20 Hz. Tests of cortical excitability and neuropsychological tests were done throughout the trial. FINDINGS: Patients generally improved with treatment. There was no perceptible difference between stimulation frequencies, which may have reflected low study power. An increase in rostral anterior cingulate activation after the treatment day was associated with increased functional connectivity in the dorso-lateral frontal loop on the left and the limbic loop on both sides. No noticeable deterioration in neuropsychological function was observed. CONCLUSION: TMS at the stimulation frequencies used seems to be safe over a course of 5000 stimuli. It appears to have an activating effect in anterior limbic structures and increase functional connectivity in the neuroanatomical networks under the stimulation coil within an hour of stimulation.
Cerebral perfusion in chronic fatigue syndrome and depression.
BACKGROUND: Patients with chronic fatigue syndrome (CFS) and depressive illness share many, but not all, features. AIMS: To test the hypothesis that patients with CFS have abnormal cerebral perfusion, that differs from that in patients with depressive illness. METHOD: We recruited 30 patients with CFS who were not depressed, 12 depressed patients and 15 healthy volunteers. Regional cerebral perfusion at rest was assessed using region of interest (ROI) and voxel-based statistical parametric mapping (SPM) techniques. RESULTS: On SPM analysis there was increased perfusion in the right thalamus, pallidum and putamen in patients with CFS and in those with depressive illness. CFS patients also had increased perfusion in the left thalamus. Depressed patients differed from those with CFS in having relatively less perfusion of the left prefrontal cortex. The results were similar on ROI analysis. CONCLUSIONS: Abnormal cerebral perfusion patterns in CFS subjects who are not depressed are similar but not identical to those in patients with depressive illness. Thalamic overactivity may be a correlate of increased attention to activity in CFS and depression; reduced prefrontal perfusion in depression may be associated with the greater neuropsychological deficits in that disorder.
Executive function and uptake of 99mTc-exametazime shown by single photon emission tomography after oral idazoxan in probable Alzheimer-type dementia.
Preliminary reports suggest improved executive function in patients with lobar dementia after treatment with single doses of the alpha 2 adrenoceptor antagonist, idazoxan. The potential for use in probable Alzheimer-type dementia prompted the present study. Fifteen patients with probable Alzheimer-type dementia were examined twice with neuropsychological measures and 14 also with single photon emission tomography (SPET) after a single double blind oral administration of 40 mg idazoxan or placebo in a balanced cross-over design. Brain perfusion maps were spatially transformed into standard stereotactic space and compared pixel-by-pixel. A parametric analysis was used to examine the relationship between the drug effect, verbal fluency and brain perfusion. Two to 3 h after idazoxan, measures of reaction time, Stroop test, category fluency and anxiety were unchanged. Verbal fluency (letter) and spatial working memory were impaired and performance on the Tower of London test in a sub-set of patients showed a trend to impairment in the idazoxan condition. Idazoxan produced a modest relative activation in left thalamus and inferior occipital cortex: decreases occurred in inferior anterior cingulate and left insular cortex. There were significant correlations on both days between measures of fluency and brain perfusion in left lateral prefrontal cortex. The reduced performance with idazoxan was directly correlated with reduced perfusion in left lateral prefrontal cortex, supporting an important interaction between drug and task performance. The imaging component of the study therefore suggested that activation of frontal networks is necessary for performing fluency tasks in Alzheimer-type dementia. Brain networks involving prefrontal cortex are the locus for the primary cognitive effects of noradrenergic drugs. The direction of the effect of any dose of agonist or antagonist may depend critically upon the age and pathology of the experimental subjects and the relationship between performance, noradrenergic drive and task difficulty.
Single photon emission computed tomography in long-term survivors of adult brain tumours.
Sixteen patients with primary brain tumours were examined on average eight years after treatment with surgery or whole brain irradiation using standard clinical assessment, CT, a neuropsychological test battery, and single photon emission CT (SPECT) with 99mTc-exametazime. Seventeen lesions were discovered on inspection of SPECT images, 11 with x-ray CT. Quantitative assessment of tracer uptake compared with 16 matched healthy volunteers was consistent with the presence of lesions. Measurement of uptake in brain regions of the hemisphere not containing the primary tumour still showed significant reductions in patients. This may be due to remote direct effects of the tumour or, more likely, to the whole brain irradiation received. Psychometric performance on most tests was significantly impaired in the patient group and was correlated with abnormalities of tracer uptake to relevant brain regions.
Primary care management of patients who self-harm.
Self-harm is best defined as 'any act of self-poisoning or self-injury carried out by an individual irrespective of motivation'. With a 10.5% lifetime risk, self-reported self-harm is common in the community. Self-harm can occur at any age but is most common in young people. Prior self-harm is the key risk factor both for repeated self-harm and also for subsequent suicide. The presence of depressive symptoms predicts repeated self-harm, as does any history of psychiatric illness. Assessment of self-harm (actual or planned) should include: details of preplanning; final acts; the event itself; what happened afterwards; as well as broader psychosocial risk factors. Patients should be asked to reflect on the episode to consider whether they regret it, or whether they are likely to repeat it. Patients should be screened for depression, anxiety, psychosis and history of self-harm. Physical illness and substance misuse increase risk. Referral to secondary care community mental health teams should be considered for patients who present in primary care with a history of self-harm and a risk of repetition. Patients with continuing thoughts or serious intent of self-harm, where supportive or protective factors cannot be identified, may need urgent referral to secondary care. Prediction of further episodes of self-harm is difficult. Some clinicians may find the use of standardised rating scales, such as the SAD PERSONS scale, a useful way to identify patients who warrant referral and further assessment. The GP should provide long-term continuity of care, and maintain a holistic awareness of a patient's life events enabling discussion of the patient's emotional problems at an early stage with the aim of intervening before a crisis.
Identifying patients at risk of perinatal mood disorders.
Perinatal mental illness influences obstetric outcomes, mother-baby interactions and longer term emotional and cognitive development of the child. Psychiatric disorders have consistently been found to be one of the leading causes of maternal deaths, often through suicide. Postnatal depression and puerperal psychosis are two disorders most commonly associated with the perinatal period. The most efficient strategy to identify patients at risk relies on focussing on clinically vulnerable subgroups: enquiries about depressive symptoms should be made at the usual screening visits. Attention should be paid to any sign of poor self-care, avoidance of eye contact, overactivity or underactivity, or abnormalities in the rate of speech. Particular care should be taken to ask about suicidal ideation and thoughts of harming others, including the baby. One of the most important risk factors is a previous history of depression. The degree of risk is directly correlated with severity of past episodes. Both antenatal and postnatal depression are being increasingly recognised in men. Puerperal psychosis is rare (1 to 2 per 1,000). Sixty per cent of women with puerperal psychosis already have a diagnosis of bipolar disorder or schizoaffective disorder. Women with a personal history of postpartum psychosis or bipolar affective disorder should be considered as high risk for postpartum psychosis. All pregnant women who are identified as being at high risk should have a shared care plan for their late pregnancy and early postnatal psychiatric management. Women with current mood disorder of mild or moderate severity who have a first-degree relative with a history of bipolar disorder or postpartum psychosis should be referred for psychiatric assessment.
The influence of ApoE4 on clinical progression of dementia: a meta-analysis.
OBJECTIVE: ApoE4 is a risk factor for the development of Alzheimer's disease, and has a functional role suggesting its importance in the neuropathology of dementia. We present a meta-analysis to investigate whether ApoE4 also affects the clinical progression of dementia in terms of cognitive decline or mortality. METHODS: We searched Medline, Embase and PsychINFO from 1990 until April 2009, for case control or cohort studies which investigated the effect of ApoE4 on progression of dementia. We identified 427 studies; 17 were suitable for inclusion. In total, there were 1733 participants with dementia at baseline, of whom 975 were heterozygous or homozygous for ApoE4. RESULTS: There was no significant difference in cognitive decline (random-model effect size = 0.02; 95% C.-I.: -0.09 to 0.14; p = 0.67) or mortality (random-model pooled odds ratio = 0.74; 95% C.-I.: 0.36 to 1.53; p = 0.41) based on the presence of ApoE4. There was no significant heterogeneity between studies using cognitive decline as an outcome. In meta-regressions of cognitive decline, duration of symptoms, age, gender and frequency of participants with ApoE4 in the samples did not contribute to outcome. CONCLUSION: Different ApoE alleles do not modify the speed of clinical progression of dementia in a way that would be detectable in a sample of 1700 patients.
A hierarchy of happiness? Mokken scaling analysis of the Oxford Happiness Inventory
The items of the Oxford Happiness Inventory (OHI), a self-report assessment of happiness, are subjected to an analysis for hierarchy among its items. By using Mokken scaling analyses we can assess whether items can reliably be ordered between persons as severity indicators on a latent trait; in this case, a latent trait of Happiness. OHI item-level data from 1024 participants were entered into the Mokken Scaling Procedure (MSP) seeking reliable scales with H > 0.30. 12 OHI items formed a reliable and statistically significant hierarchy. However, the MSP values indicate a 'weak' scale. The 'most difficult' (happiest) item on the scale is 'feeling energetic' and the 'least difficult' (least happy) is 'I have fun'. Items in the scale are consistent with what is already known about both happiness and low mood. The reduction in the OHI's items from 29 to 12 in the Mokken scale may have utility making it more accessible to participants as well as identifying items with reliably different levels of 'difficulty'. © 2010 Elsevier Ltd. All rights reserved.
Managing bipolar disorder in primary care.
Bipolar disorder is relatively common, at least twice as common as schizophrenia, and eminently treatable. It is also perfectly suited to the well established outpatient model practised in general practice and psychiatry. All GP practices should include people with a diagnosis of bipolar disorder on their case register of people with severe mental illness. It is not possible to exclude a bipolar diagnosis categorically if there are only symptoms of depression. Most patients will have had a (hypo)manic episode by their 30s. The lifetime prevalence of bipolar affective disorder proper is 1%, with a further 1.2% presenting with milder hypomanic symptoms (so-called bipolar II disorder). Relaxing diagnostic symptom criteria increases the frequency of depressed patients who develop symptoms of mania for any length of time to 50%. The lifetime course of the illness tends to be dominated by depressive episodes: half the time is estimated to be spent in the euthymic (well) state, 12% in a manic state and 38% in a depressed state. Any depressed patient should be asked about periods in the past when (s)he has been elated in mood, found it unnecessary to sleep, talked a lot, spent excessive amounts of money etc. Treatment for bipolar disorder has to be divided into: treatment of mania, treatment of bipolar depression and prophylaxis of mood swings in either direction. Antidepressant treatments are unlikely to help manic symptoms, at worst they can precipitate or aggravate them. Antimanic treatments are unlikely to help symptoms of depression but an exception to this rule would be a genuine mood stabiliser, such as lithium. Patients with bipolar disorder should have an annual physical health review. This will include monitoring for weight gain, lipid levels, plasma glucose levels, smoking status and alcohol use, as well as blood pressure.
Chronic, treatment-resistant depression and right fronto-striatal atrophy.
BACKGROUND: Treatment-resistant depression (TRD) is relatively common but its neurobiological basis is poorly understood. Fronto-striatal structural brain changes have been reported in patients with depression but their association with treatment resistance and chronicity has not been established. METHOD: Magnetic resonance images of 20 patients with TRD were compared with images of 20 recovered patients and 20 healthy controls. Images were compared using a voxel-based analysis (VBA) method; the results were validated by conventional volumetric analysis. The clinical associations of magnetic resonance imaging (MRI) changes with illness duration and severity were examined by VBA. RESULTS: Only the TRD group exhibited right fronto-striatal atrophy, and subtle MRI changes in the left hippocampus on VBA. Atrophy was confirmed on volumetric analysis, the degree correlating with the cumulative number of electroconvulsive therapy (ECT) treatments received, suggesting an acquired deficit. CONCLUSIONS: This is the first study to demonstrate fronto-striatal atrophy in patients with depression with poor outcome; the atrophy is more marked in those with more severe illness.
Increased cortical inhibition in depression: a prolonged silent period with transcranial magnetic stimulation (TMS).
BACKGROUND: Motor slowing in depression may be associated with a relative dopaminergic (DA) deficit. Bradykinesia in Parkinson's syndrome is associated with an abnormally short silent period (SP) using transcranial magnetic stimulation (TMS). We hypothesized that depression would also be associated with a short SP. METHODS: Sixteen patients with DSM-IV depression and 19 matched controls participated. SPs were elicited by exercising the contralateral abductor policis brevis (APB) during TMS. RESULTS: The SP was significantly increased in the patient group. No correlation was found between SP and depression score. CONCLUSION: A long SP suggests increased motor cortical inhibition in depression. This finding is inconsistent with the hypothesis of behavioural motor slowing in depression being associated with Parkinsonian-like mechanisms including the dopaminergic deficit. There is a need for studies incorporating larger patient groups to investigate potential correlations between SP and depression indices.
Brain activation during an auditory 'oddball task' in schizophrenia measured by single photon emission tomography.
BACKGROUND: The study examines the effect of an auditory discrimination task on regional brain perfusion in schizophrenic patients. METHODS: Twenty patients were examined with single photon emission tomography (SPET), both resting and performing an auditory two-tone 'oddball' discrimination task. Statistical parametric mapping (SPM'95) was used to identify local activation effects and correlations between event related potential measures and regional perfusion. RESULTS: Compared with rest, patients activated left superior temporal gyrus during the task, together with right caudate. There was a (negative) correlation between P300-amplitude and perfusion during the activation procedure in both caudate nuclei and in the left lingual gyrus. No correlations were observed with P300-latency. Compared with healthy volunteers examined in earlier studies, our patients showed no frontal activation. This might be due to slightly different task demands in this study, but more likely to activation-hypofrontality in schizophrenic patients compared with controls. CONCLUSION: Auditory discrimination tasks can be used in schizophrenic patients to control their 'mental set' during brain perfusion studies with SPET. This approach can yield information about specific brain mechanisms associated with such tasks, and may make comparison with healthy volunteers easier.
Correlation of auditory 'oddball' P300 with verbal memory deficits in schizophrenia.
BACKGROUND: The study attempts to recruit well known 'cognitive' event related potential measures as an objective estimate of cognitive and specific memory impairment in schizophrenia. METHODS: We examined 19 schizophrenic patients and 28 healthy controls using an auditory discrimination task to elicit event related potentials, and a number of neuropsychological tests, including tests of general intellectual ability, putative frontal lobe function and verbal memory. RESULTS: The late positive deflection presumed to be associated with stimulus evaluation (P300) was of lower amplitude and had a longer latency in the patients compared with controls of similar age and sex. We found correlations between P300 amplitude and latency, and neuropsychological performance scores in patients. There were correlations between decreased P300 amplitude and lower IQ and poorer memory performance, in particular, abnormal semantic clustering, discriminability and intrusion errors. Increased P300 latency was correlated with lower pre-morbid IQ, poorer total memory scores and serial clustering, but paradoxically less relative retrieval deficit and fewer intrusion errors. CONCLUSIONS: These findings suggest that abnormal P300 is generally more likely to occur in patients with memory impairment.