Shoumitro Deb

Separating neural correlates of allocentric and egocentric neglect: Distinct cortical sites and common white matter disconnections

Insights into the functional nature and neuroanatomy of spatial attention have come from research in neglect patients but to date many conflicting results have been reported. The novelty of the current study is that we used voxel-wise analyses based on information from segmented grey and white matter tissue combined with diffusion tensor imaging to decompose neural substrates of different neglect symptoms. Allocentric neglect was associated with damage to posterior cortical regions (posterior superior temporal sulcus, angular, middle temporal and middle occipital gyri). In contrast, egocentric neglect was associated with more anterior cortical damage (middle frontal, postcentral, supramarginal, and superior temporal gyri) and damage within subcortical structures. Damage to intraparietal sulcus (IPS) and the temporo-parietal junction (TPJ) was associated with both forms of neglect. Importantly, we showed that both disorders were associated with white matter lesions suggesting damage within long association and projection pathways such as the superior longitudinal, superior fronto-occipital, inferior longitudinal, and inferior fronto-occipital fascicule, thalamic radiation, and corona radiata. We conclude that distinct cortical regions control attention (a) across space (using an egocentric frame of reference) and (b) within objects (using an allocentric frame of reference), while common cortical regions (TPJ, IPS) and common white matter pathways support interactions across the different cortical regions.

Neuropsychiatric sequelae one year after a minor head injury

OBJECTIVE To assess neuropsychiatric sequelae 1 year after minor head injury in a cross sectional study using home interviews with patients and their relatives at 1 year after head injury. METHODS The study cohort included 148 adults who were admitted to hospital after a minor head injury between 1 July 1994 and 30 June 1995 and showed clinical or radiological evidence of brain injury. Main outcome measures used in the study were the Glasgow outcome scale, Edinburgh rehabilitation status scale, Barthel index, clinical interview schedule-revised, mini mental state examination, and assessment of symptoms of postconcussional syndrome. RESULTS At one year follow up, four (2.9%) patients had a severe disability, 35 (25.5%) had a moderate disability, and 95 (69.3%) had no disability according to the Glasgow outcome scale. A slightly higher proportion (33.3%, n=45) showed disability according to the Edinburgh rehabilitation status scale. Thirty one patients (23.1%) scored < 24 in the mini mental state examination. These were mostly patients over the age of 65. Twenty three patients (17.2%) were diagnosed as psychiatric cases according to the clinical interview schedule-revised scale. Seventy four (55.2%) patients showed one of the symptoms of postconcussional syndrome. The most commonly shown neurobehavioural problems were irritability (30%), sleep disturbance (29%), and impatience (27%). CONCLUSION One year after a minor head injury, a substantial proportion of patients showed neuropsychiatric sequelae.

International guide to prescribing psychotropic medication for the management of problem behaviours in adults with intellectual disabilities.

Psychotropic medications are used regularly to manage problem behaviours among people with intellectual disabilities. This causes concern because often these medications are used out of their licensed indications in this context. The WPA Section on Psychiatry of Intellectual Disability has recently developed an evidence and consensus-based international guide for practitioners for the use of psychotropic medications for problem behaviours among adults with intellectual disabilities. This guide advises on assessment of behaviours, producing a formulation, initiation of treatment, assessment of out-come and adverse effects, follow-up arrangements, and possibility of discontinuation of treatment.

Psychotropic medication for behaviour problems in people with intellectual disability: a review of the current literature.

Purpose of review A high proportion of people with intellectual disability have behaviour problems and psychotropic medication is a commonly used management strategy for these behaviours, despite lack of good-quality evidence to support this practice. Recent findings In recent years, one randomized controlled trial among adults and four on children with intellectual disability have been published showing effectiveness of low-dose risperidone in the management of behaviour problems as compared with placebo. Most of these randomized controlled trials are of good quality and included a reasonable number of participants. Most of these studies showed adverse effects, however, somnolence and weight gain particularly being associated with risperidone treatment. Most of the evidence on other psychotropic medications such as antidepressants, mood stabilizers, antianxiety drugs and opioid antagonists is difficult to interpret because it is based primarily on small case studies. Summary There is growing evidence in support of some antipsychotic medication, particularly the atypical antipsychotic, risperidone. Many of the studies of effectiveness included in this review have methodological flaws however. Therefore, the results need to be interpreted with caution. Furthermore, the paucity of evidence for some groups of medication does not necessarily mean that these medications are ineffective, but rather that their use is not currently supported by good-quality research.

Neuropsychiatric consequences of traumatic brain injury: a comparison between two age groups.

Background: Neurobehavioural symptoms and certain psychiatric disorders are common after a traumatic brain injury (TBI). Relatively few studies have investigated the effect of age upon these outcomes. Aim: Our aim was to compare the rates of neurobehavioural symptoms and psychiatric disorders between 18–65 year old and over 65 year old patients with TBI. Method: 120 adults aged 18 to 65 years and 45 adults over 65 years of age who were admitted to a hospital following a TBI were assessed for neurobehavioural symptoms and psychiatric disorders one year after the injury. Results: Our estimate suggested that a higher proportion of 18–65 year old patients (32%) had ICD-10 psychiatric disorders according to the Schedule for Clinical Assessment in Neuropsychiatry (SCAN) interview compared with patients over 65 years of age (16%). Similarly, the ICD-10 depressive disorder was more common among the younger patients (16%) than the older group of patients (11%). None of these differences were statistically significant. However, a multiple regression analysis revealed that among other risk factors, a younger age was significantly associated with the presence of a psychiatric disorder. Also, a significantly higher rate of psychiatric caseness was detected among the younger age group using screening instruments such as the General Health Questionniare-28 (GHQ-28) (p < 0.01) and the Clinical Interview Schedule-Revised (CIS-R) (p < 0.01). The rates of individual neurobehavioural symptoms varied significantly between the two age groups. The most prevalent symptoms in 18–65 year olds were irritability (37%) and sleep problems (37%). In the older group of patients the most prevalent symptoms were poor memory (40%), dependence (38%) and slowness in thinking (33%). Conclusion: 18–65 year old patients are likely to be at a greater risk of psychiatric morbidity following TBI than over 65 year olds whereas neurobehavioural symptoms are prevalent in both age groups.

Review of subjectThe role of pharmacotherapy in the management of behaviour disorders in traumatic brain injury patients

The aim of this paper was to systematically review the research published in English language on the effectiveness of drugs for the treatment of neurobehavioural disorders in patients with traumatic brain injury (TBI). A literature search using Medline, Pre-Medline, Embase, Psychlit and Cochrane Library databases between 1990 and January 2003 as well as a hand search of Brain Injury since 1996 were carried out. Phrases such as ‘head injury’, ‘brain injury’, ‘drug treatment’, ‘drug trials’ and ‘randomized controlled trials’ were used. Sixty-three papers were selected for data synthesis. Of these, 13 were randomized controlled trials, eight were prospective observational studies, four were retrospective studies, 25 were case series and 13 were single case studies. There was a dearth of type I-III evidence. There was no strong evidence either way to suggest that drugs are effective in the treatment of behaviour disorders in patients with TBI. However, there was weak evidence, primarily based on case studies that psychostimulants are effective in the treatment of apathy, inattention and slowness; high dose beta-blockers in the treatment of agitation and aggression; anti-convulsants and anti-depressants (particularly SSRIs) in the treatment of agitation and aggression, particularly in the context of an affective disorder; and possibly a specific neuroleptic methotrimeprazine in the treatment of agitation in the post-acute stage of Acquired Brain Injury. Some drugs that are effective in some patients have been shown to be ineffective in others. Some drugs, particularly lithium and dopaminergic drugs could cause adverse effects and deterioration in some patients.

The effectiveness of mood stabilizers and antiepileptic medication for the management of behaviour problems in adults with intellectual disability: a systematic review

BACKGROUND Psychotropic medications are used to manage behaviour problems in adults with intellectual disability (ID). One group of psychotropic medication are mood stabilizers such as lithium and some antiepileptic drugs. METHOD A comprehensive systematic review was performed to determine the evidence base for the effectiveness of mood stabilizers in the management of behaviour problems among adults with ID. Electronic searches of PsycInfo, Medline, Embase and Cinahl databases were conducted, as well as a thorough hand search for relevant literature. We reviewed primary trials relating to adults only that satisfied strict inclusion criteria. RESULTS One randomized controlled trial (RCT) relating to lithium use and two non-RCTs, one on lithium and the other on carbamazepine, were revealed. In addition, one prospective non-controlled trial on sodium valproate and three retrospective case series studies were discovered, of which one considered the efficacy of lithium, one valproate and one topiramate. CONCLUSIONS The current evidence lends some support for the use of lithium and some antiepileptic mood stabilizer medication for the management of behaviour problems in adults with ID. However, because most studies reviewed here are riddled with obvious methodological constrains, the findings have to be interpreted with caution.

The neural underpinings of simultanagnosia: Disconnecting the visuospatial attention network

Because of our limited processing capacity, different elements of the visual scene compete for the allocation of processing resources. One of the most striking deficits in visual selection is simultanagnosia, a rare neuropsychological condition characterized by impaired spatial awareness of more than one object at time. To decompose the neuroanatomical substrates of the syndrome and to gain insights into the structural and functional organization of visuospatial attention, we performed a systematic evaluation of lesion patterns in a group of simultanagnosic patients compared with patients with either (i) unilateral visuospatial deficits (neglect and/or extinction) or (ii) bilateral posterior lesions without visuospatial deficits, using overlap/subtraction analyses, estimation of lesion volume, and a lesion laterality index. We next used voxel-based morphometry to assess the link between different visuospatial deficits and gray matter and white matter (WM) damage. Lesion overlap/subtraction analyses, lesion laterality index, and voxel-based morphometry measures converged to indicate that bilateral parieto-occipital WM disconnections are both distinctive and necessary to create symptoms associated with simultanagnosia. We also found that bilateral gray matter damage within the middle frontal area (BA 46), cuneus, calacarine, and parieto-occipital fissure as well as right hemisphere parietal lesions within intraparietal and postcentral gyri were associated with simultanagnosia. Further analysis of the WM based on tractography revealed associations with bilateral damage to major pathways within the visuospatial attention network, including the superior longitudinal fasciculus, the inferior fronto-occipital fasciculus, and the inferior longitudinal fasciculus. We conclude that damage to the parieto-occipital regions and the intraparietal sulcus, together, with bilateral WM disconnections within the visuosptial attention network, contribute to poor visual processing of multiple objects and the loss of processing speed characteristic of simultanagnosia.

ICD-10 codes detect only a proportion of all head injury admissions.

Despite criticism, the codes covering traumatic brain injury under the International Classification of Diseases have been widely used for sample collection in the epidemiological studies of head injury. Data have been collected from an Accident and Emergency departments (A&Es) case register on all head injury admissions to hospitals from a defined geographic area between 1 April 1996 and 31 March 1997, and compared with the list collected from the heath authoritys central database by using the ICD-10 codes. Thirty seven per cent of the names in the A&E register appeared in the ICD-10 list, and 41% of the names in the ICD-10 list appeared in the list collected from the A&E department. The incidence of reported head injury was found to be three times higher among the 0-15 years age group compared with the 16-64 years age group (3.3% compared with 1% of the population). Among the 16-64 years age group, the peak rates of admission to hospital were in the months of February and August. Approximately 14% of all the head injury admissions stayed in hospital for more than 72 hours, another 14% stayed between 48 and 72 hours, and the rest (72%) stayed for less than 48 hours.

Are opioid antagonists effective in attenuating the core symptoms of autism spectrum conditions in children: a systematic review

BACKGROUND ASC (autism spectrum conditions) may result from a failure of striatal beta endorphins to diminish with maturation. Many symptoms of ASC resemble behaviours induced in animals or humans by opiate administration, including decreased socialisation, diminished crying, repetitive stereotypies, insensitivity to pain and motor hyperactivity. Naltrexone, an opioid antagonist, has been used in the management of children with ASC and can produce a clinically significant reduction in the serious and life-threatening behaviour of self-injury for individuals who have not been responsive to any other type of treatment and is important for this reason. It was therefore appropriate to reconsider the available evidence and a systematic review was undertaken. METHODS Four electronic databases were searched for relevant journal articles. In addition, cross-referencing of pertinent reviews and a hand search for articles in major international intellectual disability (ID) journals between the years 2010 and 2012 was carried out to ensure that all relevant articles were identified. We also searched databases for unpublished clinical trials to overcome publication bias. Each database was searched up to present (February 2013) with no restrictions on the date of publication. The search terms consisted of broad expressions used to describe ID and autistic spectrum disorder as well as terms relating to opioid antagonists and specific drugs. All studies identified by the electronic database search and hand search were examined on the basis of title alone for relevance and duplication. The abstracts of the remaining papers were then scrutinised against the inclusion criteria. Where abstracts failed to provide adequate information, the full texts for these papers were obtained. All the full texts were then evaluated against the inclusion proforma. Two reviewers carried out all the stages of the process independently. The reviewers met to discuss their selections and where disagreements arose, these were settled by discussion with a member of the study group. Data from each study meeting the inclusion criteria were extracted on a pre-piloted data extraction form. The quality of each study was further assessed using the Jadad scale, a tool developed to assess the quality of randomised controlled trials. RESULTS 155 children participated in 10 studies; 27 received placebo. Of the 128 that received naltrexone 98 (77%) showed statistically significant improvement in symptoms of irritability and hyperactivity. Side effects were mild and the drug was generally well tolerated. CONCLUSIONS Naltrexone may improve hyperactivity and restlessness in children with autism but there was not sufficient evidence that it had an impact on core features of autism in majority of the participants. It is likely that a subgroup of children with autism and abnormal endorphin levels may respond to naltrexone and identifying the characteristics of these children must become a priority.