Characterizing Subcortical Structural Heterogeneity in Autism

Autism presents with significant phenotypic and neuroanatomical heterogeneity, and neuroimaging studies of the thalamus, globus pallidus and striatum in autism have produced inconsistent and contradictory results. These structures are critical mediators of functions known to be atypical in autism, including sensory gating and motor function. We examined both volumetric and fine-grained localized shape differences in autism using a large (n=3145, 1045-1318 after strict quality control), cross-sectional dataset of T1-weighted structural MRI scans from 32 sites, including both males and females (assigned-at-birth). We investigated three potentially important sources of neuroanatomical heterogeneity: sex, age, and intelligence quotient (IQ), using a meta-analytic technique after strict quality control to minimize non-biological sources of variation. We observed no volumetric differences in the thalamus, globus pallidus, or striatum in autism. Rather, we identified a variety of localized shape differences in all three structures. Including age, but not sex or IQ, in the statistical model improved the fit for both the pallidum and striatum, but not for the thalamus. Age-centered shape analysis indicated a variety of age-dependent regional differences. Overall, our findings help confirm that the neurodevelopment of the striatum, globus pallidus and thalamus are atypical in autism, in a subtle location-dependent manner that is not reflected in overall structure volumes, and that is highly non-uniform across the lifespan.

Examining the Boundary Sharpness Coefficient as an Index of Cortical Microstructure in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is associated with atypical brain development. However, the phenotype of regionally specific increased cortical thickness observed in ASD may be driven by several independent biological processes that influence the gray/white matter boundary, such as synaptic pruning, myelination, or atypical migration. Here, we propose to use the boundary sharpness coefficient (BSC), a proxy for alterations in microstructure at the cortical gray/white matter boundary, to investigate brain differences in individuals with ASD, including factors that may influence ASD-related heterogeneity (age, sex, and intelligence quotient). Using a vertex-based meta-analysis and a large multicenter structural magnetic resonance imaging (MRI) dataset, with a total of 1136 individuals, 415 with ASD (112 female; 303 male), and 721 controls (283 female; 438 male), we observed that individuals with ASD had significantly greater BSC in the bilateral superior temporal gyrus and left inferior frontal gyrus indicating an abrupt transition (high contrast) between white matter and cortical intensities. Individuals with ASD under 18 had significantly greater BSC in the bilateral superior temporal gyrus and right postcentral gyrus; individuals with ASD over 18 had significantly increased BSC in the bilateral precuneus and superior temporal gyrus. Increases were observed in different brain regions in males and females, with larger effect sizes in females. BSC correlated with ADOS-2 Calibrated Severity Score in individuals with ASD in the right medial temporal pole. Importantly, there was a significant spatial overlap between maps of the effect of diagnosis on BSC when compared with cortical thickness. These results invite studies to use BSC as a possible new measure of cortical development in ASD and to further examine the microstructural underpinnings of BSC-related differences and their impact on measures of cortical morphology.

Large-scale analyses of the relationship between sex, age and intelligence quotient heterogeneity and cortical morphometry in autism spectrum disorder

Significant heterogeneity across aetiologies, neurobiology and clinical phenotypes have been observed in individuals with autism spectrum disorder (ASD). Neuroimaging-based neuroanatomical studies of ASD have often reported inconsistent findings which may, in part, be attributable to an insufficient understanding of the relationship between factors influencing clinical heterogeneity and their relationship to brain anatomy. To this end, we performed a large-scale examination of cortical morphometry in ASD, with a specific focus on the impact of three potential sources of heterogeneity: sex, age and full-scale intelligence (FIQ). To examine these potentially subtle relationships, we amassed a large multi-site dataset that was carefully quality controlled (yielding a final sample of 1327 from the initial dataset of 3145 magnetic resonance images; 491 individuals with ASD). Using a meta-analytic technique to account for inter-site differences, we identified greater cortical thickness in individuals with ASD relative to controls, in regions previously implicated in ASD, including the superior temporal gyrus and inferior frontal sulcus. Greater cortical thickness was observed in sex specific regions; further, cortical thickness differences were observed to be greater in younger individuals and in those with lower FIQ, and to be related to overall clinical severity. This work serves as an important step towards parsing factors that influence neuroanatomical heterogeneity in ASD and is a potential step towards establishing individual-specific biomarkers.

Default Mode Hypoconnectivity Underlies a Sex-Related Autism Spectrum

Background

Females and males differ significantly in the prevalence and presentation of autism spectrum conditions. One theory of this effect postulates that autistic traits lie on a sex-related continuum in the general population, and autism represents the extreme male end of this spectrum. This theory predicts that any feature of autism in males should 1) be present in autistic females, 2) differentiate between the sexes in the typical population, and 3) correlate with autistic traits. We tested these three predictions for default mode network (DMN) hypoconnectivity during the resting state, one of the most robustly found neurobiological differences in autism.

Methods

We analyzed a primary dataset of adolescents (N = 121, 12–18 years of age) containing a relatively large number of females and a replication multisite dataset including children, adolescents, and adults (N = 980, 6–58 years of age). We quantified the average connectivity between DMN regions and tested for group differences and correlation with behavioral performance using robust regression.

Results

We found significant differences in DMN intraconnectivity between female controls and females with autism (p = .001 in the primary dataset; p = .009 in the replication dataset), and between female controls and male controls (p = .036 in the primary dataset; p = .002 in the replication dataset). We also found a significant correlation between DMN intraconnectivity and performance on a mentalizing task (p = .001) in the primary dataset.

Conclusions

Collectively, these findings provide the first evidence for DMN hypoconnectivity as a behaviorally relevant neuroimaging phenotype of the sex-related spectrum of autistic traits, of which autism represents the extreme case.

Developmental white matter microstructure in autism phenotype and corresponding endophenotype during adolescence

During adolescence, white matter microstructure undergoes an important stage of development. It is hypothesized that the alterations of brain connectivity that have a key role in autism spectrum conditions (ASCs) may interact with the development of white matter microstructure. This interaction may be present beyond the phenotype of autism in siblings of individuals with ASC, who are 10 to 20 times more likely to develop certain forms of ASC. We use diffusion tensor imaging to examine how white matter microstructure measurements correlate with age in typically developing individuals, and how this correlation differs in n=43 adolescents with ASC and their n=38 siblings. Correlations observed in n=40 typically developing individuals match developmental changes noted in previous longitudinal studies. In comparison, individuals with ASC display weaker negative correlation between age and mean diffusivity in a broad area centred in the right superior longitudinal fasciculus. These differences may be caused either by increased heterogeneity in ASC or by temporal alterations in the group's developmental pattern. Siblings of individuals with ASC also show diminished negative correlation between age and one component of mean diffusivity-second diffusion eigenvalue-in the right superior longitudinal fasciculus. As the observed differences match for location and correlation directionality in our comparison of typically developing individuals to those with ASC and their siblings, we propose that these alterations constitute a part of the endophenotype of autism.

Psychological correlates of handedness and corpus callosum asymmetry in autism: the left hemisphere dysfunction theory revisited

Rightward cerebral lateralization has been suggested to be involved in the neuropathology of autism spectrum conditions. We investigated functional and neuroanatomical asymmetry, in terms of handedness and corpus callosum measurements in male adolescents with autism, their unaffected siblings and controls, and their associations with executive dysfunction and symptom severity. Adolescents with autism did not differ from controls in functional asymmetry, but neuroanatomically showed the expected pattern of stronger rightward lateralization in the posterior and anterior midbody based on their hand-preference. Measures of symptom severity were related to rightward asymmetry in three subregions (splenium, posterior midbody and rostral body). We found the opposite pattern for the isthmus and rostrum with better cognitive and less severe clinical scores associated with rightward lateralization.

Autism spectrum disorder in Chinese populations: a brief review

This review summarizes the published work on the prevalence and incidence rates of autism spectrum disorder (ASD) in Chinese populations. The authors searched MEDLINE, Web of Science and the PsycINFO database and identified seven studies that were published in the English language. In mainland China, Li and colleagues reported an autism prevalence rate of 2.38/10,000 but admitted the possibility of underestimation. A higher prevalence of 11/10,000 was reported by Zhang and Ji based on a survey that was conducted in Tianjin, China. In Taiwan, Chien and colleagues reported that the cumulative prevalence of ASD increased from 1.79 to 28.72/10,000 from 1996 to 2005 and the annual incidence rate increased from 0.91 to 4.41/10,000 per year from 1997 to 2005. Another study based on the Taiwan national health insurance database reported a high prevalence rate of 122.8/10,000 for the year 2007. Two studies based on the Taiwan national disability registry data reported an increasing trend of ASD for the period 2000-2007 and 2004-2010, respectively. In Hong Kong, Wong and colleagues estimated that the incidence of ASD was 5.49/10,000 and the average prevalence over the 1986-2005 period was 16.1/10,000. We identified 12 studies through the searching of Chinese databases. The prevalences among these studies varied from 2.8 to 29.5/10,000. While existing data appear to suggest, it remains unclear whether there is a true rise in the prevalence of ASD in ethnic Chinese population across geographic sites. More collaborative research on this topic should be conducted in the future.

Failure to deactivate the default mode network indicates a possible endophenotype of autism

Background

Reduced activity during cognitively demanding tasks has been reported in the default mode network in typically developing controls and individuals with autism. However, no study has investigated the default mode network (DMN) in first-degree relatives of those with autism (such as siblings) and it is not known whether atypical activation of the DMN is specific to autism or whether it is also present in unaffected relatives. Here we use functional magnetic resonance imaging to investigate the pattern of task-related deactivation during completion of a visual search task, the Embedded Figures Task, in teenagers with autism, their unaffected siblings and typically developing controls.

Findings

We identified striking reductions in deactivation during the Embedded Figures Task in unaffected siblings compared to controls in brain regions corresponding to the default mode network. Adolescents with autism and their unaffected siblings similarly failed to deactivate regions, including posterior cingulate and bilateral inferior parietal cortex.

Conclusions

This suggests that a failure to deactivate these regions is a functional endophenotype of autism, related to familial risk for the condition shared between individuals with autism and their siblings.

Atypical activation during the Embedded Figures Task as a functional magnetic resonance imaging endophenotype of autism

Atypical activation during the Embedded Figures Task has been demonstrated in autism, but has not been investigated in siblings or related to measures of clinical severity. We identified atypical activation during the Embedded Figures Task in participants with autism and unaffected siblings compared with control subjects in a number of temporal and frontal brain regions. Autism and sibling groups, however, did not differ in terms of activation during this task. This suggests that the pattern of atypical activation identified may represent a functional endophenotype of autism, related to familial risk for the condition shared between individuals with autism and their siblings. We also found that reduced activation in autism relative to control subjects in regions including associative visual and face processing areas was strongly correlated with the clinical severity of impairments in reciprocal social interaction. Behavioural performance was intact in autism and sibling groups. Results are discussed in terms of atypical information processing styles or of increased activation in temporal and frontal regions in autism and the broader phenotype. By separating the aspects of atypical activation as markers of familial risk for the condition from those that are autism-specific, our findings offer new insight into the factors that might cause the expression of autism in families, affecting some children but not others.

Evaluation of a screening instrument for autism spectrum disorders in prisoners

There have been concerns that individuals with autism spectrum disorders (ASDs) are over-represented but not recognised in prison populations. A screening tool for ASDs in prisons has therefore been developed.

Facial emotion recognition in Scottish prisoners

BACKGROUND

Studies of antisocial populations have found that they show deficits in recognition of facial affect. Such deficits are also found in other populations with clinical conditions such as autism spectrum disorders, schizophrenia and obsessive compulsive disorder.

AIMS

We aimed to investigate the hypothesis that facial affect recognition in the Scottish prison population would differ from matched controls. In addition, we aimed to investigate any relationship between facial affect recognition deficits and offence history.

METHODS

A sample of serving convicted prisoners, drawn from a larger study, was assessed for ability to recognise facial affect. Other variables were also measured and a self-report offending history obtained.

RESULTS

127 prisoners were assessed in 11 prisons. Male prisoners were significantly worse than age, sex and IQ-matched controls at recognising negative facial emotions, specifically anger, fear, sadness and disgust. Within the sample of prisoners, deficits in fear recognition were associated with a history of previous prison sentences but not previous convictions. With respect to offending history, sex offenders were relatively better at recognising sadness and worse at recognising surprise than the other offenders. These relationships remain after controlling for IQ.

CONCLUSIONS

Scottish convicted prisoners show deficits in recognising negative facial emotions in a pattern consistent with other antisocial populations. We also demonstrated a relationship between particular patterns of deficit and types of offending history not previously described.

A novel functional brain imaging endophenotype of autism: the neural response to facial expression of emotion

Siblings of individuals with autism have over 20 times the population risk of autism. Evidence of comparable, but less marked, cognitive and social communication deficits in siblings suggests a role for these traits in the search for biomarkers of familial risk. However, no neuroimaging biomarkers of familial risk have been identified to date. Here we show, for the first time, that the neural response to facial expression of emotion differs between unaffected siblings and healthy controls with no family history of autism. Strikingly, the functional magnetic resonance imaging (fMRI) response to happy versus neutral faces was significantly reduced in unaffected siblings compared with controls within a number of brain areas implicated in empathy and face processing. The response in unaffected siblings did not differ significantly from the response in autism. Furthermore, investigation of the response to faces versus fixation crosses suggested that, within the context of this study, an atypical response specifically to happy faces, rather than to faces in general, accounts for the observed sibling versus controls difference and is a clear biomarker of familial risk. Our findings suggest that an atypical implicit response to facial expression of emotion may form the basis of impaired emotional reactivity in autism and in the broader autism phenotype in relatives. These results demonstrate that the fMRI response to facial expression of emotion is a candidate neuroimaging endophenotype for autism, and may offer far-reaching insights into the etiology of autism.

Health status in the TORCH study of COPD: treatment efficacy and other determinants of change

BACKGROUND

Little is known about factors that determine health status decline in clinical trials of COPD.

OBJECTIVES

To examine health status changes over 3 years in the TORCH study of salmeterol+fluticasone propionate (SFC) vs. salmeterol alone, fluticasone propionate alone or placebo.

METHODS

St George's Respiratory Questionnaire (SGRQ) was administered at baseline then every 6 months.

MEASUREMENTS AND MAIN RESULTS

Data from 4951 patients in 28 countries were available. SFC produced significant improvements over placebo in all three SGRQ domains during the study: (Symptoms -3.6 [95% CI -4.8, -2.4], Activity -2.8 [95% CI -3.9, -1.6], Impacts -3.2 [95% CI -4.3, -2.1]) but the pattern of change over time differed between domains. SGRQ deteriorated faster in patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages III & IV relative to GOLD stage II (p < 0.001). There was no difference in the relationship between deterioration in SGRQ Total score and forced expiratory volume in one second (FEV1) decline (as % predicted) in men and women. Significantly faster deterioration in Total score relative to FEV1 % predicted was seen in older patients (≥ 65 years) and there was an age-related change in Total score that was independent of change in FEV1. The relationship between deterioration in FEV1 and SGRQ did not differ in different world regions, but patients in Asia-Pacific showed a large improvement in score that was unrelated to FEV1 change.

CONCLUSIONS

In addition to treatment effects, health status changes in clinical trials may be influenced by demographic and disease-related factors. Deterioration in health status appears to be fastest in older persons and those with severe airflow limitation.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00268216.

Low birthweight and preterm birth in young people with special educational needs: a magnetic resonance imaging analysis

BACKGROUND

Although neuroanatomical and cognitive sequelae of low birthweight and preterm birth have been investigated, little is understood as to the likely prevalence of a history of low birthweight or preterm birth, or neuroanatomical correlates of such a history, within the special educational needs population. Our aim was to address these issues in a sample of young people receiving additional learning support.

METHODS

One hundred and thirty-seven participants aged 13-22 years, receiving additional learning support, were recruited via their schools or colleges and underwent structural magnetic resonance imaging (MRI). Obstetric records, available in 98 cases, included birthweight and gestational data in 90 and 95 cases, respectively. Both qualitative and quantitative voxel-based analyses of MRI data were conducted.

RESULTS

A history of low birthweight and preterm birth was present in 13.3% and 13.7% of cases, respectively. Low birthweight and preterm birth were associated with specific qualitative anomalies, including enlargement of subarachnoid cisterns and thinning of the corpus callosum. Low birthweight was associated with reduced grey matter density (GMD) in the superior temporal gyrus (STG) bilaterally, left inferior temporal gyrus and left insula. Prematurity of birth was associated with reduced GMD in the STG bilaterally, right inferior frontal gyrus and left cerebellar hemisphere. Comparison of subjects with no history of low birthweight or preterm birth with a previously defined control sample of cognitively unimpaired adolescents (n = 72) demonstrated significantly greater scores for several anomalies, including thinning of the corpus callosum, loss of white matter and abnormalities of shape of the lateral ventricles.

CONCLUSION

Although a two-fold increased prevalence of a history of low birthweight and preterm birth exists within the special educational needs population, other aetiological factors must be considered for the overwhelming majority of cases. Neuroanatomical findings within this sample include qualitative anomalies of brain structure and grey matter deficits within temporal lobe structures and the cerebellum that persist into adolescence. These findings suggest a neurodevelopmental mechanism for the cognitive difficulties associated with these obstetric risk factors.

Autistic traits and cognitive performance in young people with mild intellectual impairment

Cognitive performance and the relationship between theory of mind (TOM), weak central coherence and executive function were investigated in a cohort of young people with additional learning needs. Participants were categorized by social communication questionnaire score into groups of 10 individuals within the autistic spectrum disorder (ASD) range, 14 within the pervasive developmental disorder range and 18 with few autistic traits. The ASD group were significantly poorer than the other groups on a test of cognitive flexibility. In the ASD group only, there was a strong relationship between executive performance and TOM which remained after controlling for IQ. Our findings suggest that the relationship between cognitive traits may more reliably distinguish autism than the presence of individual deficits alone.

Schizotypal cognitions as a predictor of psychopathology in adolescents with mild intellectual impairment

BACKGROUND

There is evidence to suggest that among young people with mild intellectual disability there are those whose cognitive difficulties may predict the subsequent manifestation of a schizophrenic phenotype. It is suggested that they may be detectable by simple means.

AIMS

To gain adequate cooperation from educational services, parents and students so as to recruit a sufficiently large sample to test the above hypothesis, and to examine the hypothesis in the light of the findings.

METHOD

The sample was screened with appropriate instruments, and groups hypothesised as being likely or not likely to have the phenotype were compared in terms of psychopathology and neuropsychology.

RESULTS

Simple screening methods detect a sample whose psychopathological and neuropsychological profile is consistent with an extended phenotype of schizophrenia.

CONCLUSIONS

Difficulties experienced by some young people with mild and borderline intellectual disability are associated with enhanced liability to schizophrenia. Clinical methods can both identify those with this extended phenotype and predict those in whom psychosis will occur.

Towards a neuroanatomy of autism: a systematic review and meta-analysis of structural magnetic resonance imaging studies

BACKGROUND

Structural brain abnormalities have been described in autism but studies are often small and contradictory. We aimed to identify which brain regions can reliably be regarded as different in autism compared to healthy controls.

METHOD

A systematic search was conducted for magnetic resonance imaging studies of regional brain size in autism. Data were extracted and combined using random effects meta-analysis. The modifying effects of age and IQ were investigated using meta-regression.

RESULTS

The total brain, cerebral hemispheres, cerebellum and caudate nucleus were increased in volume, whereas the corpus callosum area was reduced. There was evidence for a modifying effect of age and IQ on the cerebellar vermal lobules VI-VII and for age on the amygdala.

CONCLUSIONS

Autism may result from abnormalities in specific brain regions and a global lack of integration due to brain enlargement. Inconsistencies in the literature partly relate to differences in the age and IQ of study populations. Some regions may show abnormal growth trajectories.

Structural correlates of intellectual impairment and autistic features in adolescents

Intellectual disability, a common but under-researched condition, is strongly associated with autism spectrum disorders (ASD). Although studies have investigated the neural correlates of intelligence quotient (IQ) and ASD in intellectually unimpaired subjects, these issues have not been addressed in intellectually impaired subjects. We studied 63 intellectually disabled adolescents receiving additional learning support and 72 controls using whole brain tissue volumes extracted from native space and voxel-based morphometry (VBM) in normalised space. We applied a qualitative and quantitative review of VBM preprocessing and modified the optimised method to establish optimum co-registration of the brains in normalised space. We report tissue density differences at cluster level with adjustment for underlying smoothness. Individuals with intellectual disability had smaller total white matter and total brain tissue volumes than controls, as well as reduced grey matter density in the right cerebellar hemisphere and left temporo-parietal cortex, and reduced white matter density in the posterior corpus callosum. Intellectually disabled subjects were additionally subgrouped according to their degree of reported autistic features. Reduced grey matter density was detected in the thalamus of subjects with autistic features scoring within the pervasive developmental disorder range as compared to subjects below the threshold for ASD, and increased white matter density was detected in the left superior temporal gyrus of subjects scoring above the threshold for autism as compared to subjects below the threshold for ASD.

Estimating the cost-effectiveness of fluticasone propionate for treating chronic obstructive pulmonary disease in the presence of missing data

OBJECTIVES

To explore the cost-effectiveness of fluticasone propionate (FP) for the treatment of chronic obstructive pulmonary disease (COPD), we estimated costs and quality-adjusted life-years (QALYs) over 3 years, based on an economic appraisal of a previously reported clinical trial (Inhaled Steroids in Obstructive Lung Disease in Europe [ISOLDE]).

METHODS

Seven hundred forty-two patients enrolled in the ISOLDE trial who received either FP or placebo had data available on health-care costs and quality of life over the period of the study. The SF-36-based utility scores for quality of life were used to calculate QALYs. A combined imputation and bootstrapping procedure was employed to handle missing data and to estimate statistical uncertainty in the estimated cumulative costs and QALYs over the study period. The imputation approach was based on propensity scoring and nesting this approach within the bootstrap ensured that multiple imputations were performed such that statistical estimates included imputation uncertainty.

RESULTS

Complete data were available on mortality within the follow-up period of the study and a nonsignificant trend toward improved survival of 0.06 (95% confidence interval [CI]-0.01 to 0.15) life-years was observed. In an analysis based on a propensity scoring approach to missing data we estimated the incremental costs of FP versus placebo to be 1021 sterling pound(95% CI 619-1338 sterling pound) with an additional effect of 0.11 QALYs (CI 0.04-0.20). Cost-effectiveness estimates for the within-trial period of 17,700 sterling pound per life-year gained (6900 sterling pound to infinity) and 9500 sterling pound per QALY gained (CI 4300-26,500 sterling pound) were generated that include uncertainty due to the imputation process. An alternative imputation approach did not materially affect these estimates.

CONCLUSIONS

Previous analyses of the ISOLDE study showed significant improvement on disease-specific health status measures and a trend toward a survival advantage for treatment with FP. This analysis shows that joint considerations of quality of life and survival result in a substantial increase in QALYs favoring treatment with FP. Based on these data, the inhaled corticosteroid FP appears cost-effective for the treatment of COPD. Confirmation or refutation of this result may be achieved once the Towards a Revolution in COPD Health (TORCH) study reports, a large randomized controlled trial powered to detect mortality changes associated with the use of FP alone, or in combination with salmeterol, which is also collecting resource use and utility data suitable for estimating cost-effectiveness.

Economic evaluation of treating chronic obstructive pulmonary disease with inhaled corticosteroids and long-acting beta2-agonists in a health maintenance organization

OBJECTIVES

In light of recent results from observational studies showing prolonged survival in subjects taking long-acting beta2-agonists (LABA) and/or inhaled corticosteroids (ICS) for chronic obstructive pulmonary disease (COPD), we investigated their cost-effectiveness (CE).

METHODS

Costs and survival data were collected for a sample of members enrolled in a large Health Maintenance Organization in the United States. An observational study design was used to evaluate cumulative costs and health benefits of LABA, ICS, ICS+LABA, or comparison drugs. Survival was estimated using a parametric regression model. Costs were adjusted for censoring and prognostic factors. CE was evaluated over a time horizon of 36 months and the remaining lifetime of subjects.

RESULTS

Over 36 months, life expectancy and costs were: 2.4 years (95% confidence interval (CI): 2.3; 2.5) and $28,030 (CI: $23,400; $33,570) for not receiving ICS or LABA; 2.6 years (CI: 2.6; 2.7) and $35,170 (CI: $29,970; $40,620) for ICS alone; 2.6 years (CI: 2.5; 2.7) and $27,380 (CI: $21,780; $32,510) for LABA alone; and, 2.7 years (CI: 2.6; 2.8) and $33,780 (CI: $28,700; $39,440) for subjects treated with ICS+LABA. The lifetime analysis showed similar trends.

CONCLUSIONS

There is an acute need to find effective, life-extending treatments for persons with COPD. ICS, LABA or their combination represent promising treatment options and are currently being tested in randomized trials. If the impact on survival seen in these trials compares to that seen in observational studies, LABA and the combination treatment are likely to be cost-effective in the United States.

Empirical comparison of maximal voxel and non-isotropic adjusted cluster extent results in a voxel-based morphometry study of comorbid learning disability with schizophrenia

We present an empirical comparison of cluster extent and maximal voxel results in a voxel-based morphometry (VBM) study of brain structure. The cluster extents are adjusted for underlying deviation from uniform smoothness. We implement this comparison on a four-group cohort that has previously shown evidence of a neuro-developmental component in schizophrenia (Moorhead, T.W.J., Job, D.E., Whalley, H.C., Sanderson, T.L., Johnstone, E.C. and Lawrie, S.M. 2004. Voxel-based morphometry of comorbid schizophrenia and learning disability: analyses in normalized and native spaces using parametric and nonparametric statistical methods. NeuroImage 22: 188-202.). We find that adjusted cluster extent results provide information on the nature of deficits that occur in the schizophrenia affected groups, and these important structural differences are not all shown in maximal voxel results. The maximal voxel and cluster extent results are corrected for multiple comparisons using Random Fields (RF) methods. In order to apply the cluster extent measures, we propose a post-hoc method for determining the primary threshold in the analysis. Unadjusted cluster extent results are reported, for these, no allowance is made for non-isotropic smoothness, and comparison with the adjusted extent results shows that the unadjusted results can be either conservative or anti-conservative depending upon the underlying tissue distributions.

Qualitative assessment of brain anomalies in adolescents with mental retardation

BACKGROUND AND PURPOSE

The neural basis of mental retardation is poorly understood. This study aimed to characterize structural anomalies of the brain in mental retardation and the relationship between them and the degree of mental retardation.

METHODS

Eighty adolescents receiving educational support and 40 controls underwent MR brain imaging and intelligence quotient (IQ) assessment. MR images were evaluated according to a checklist of qualitative brain anomalies by a neuroradiologist blind to group membership. All scans were assessed by a second neuroradiologist to measure interobserver agreement. Ten percent of the studies were randomly selected for assessment of intraobserver agreement.

RESULTS

Evaluation of MR images by using the checklist generated results with a high degree of interobserver and intraobserver agreement. Intraclass correlations were 0.93 and 0.75 for interobserver agreement on the total abnormality score and the entire checklist, respectively, and 0.97 and 0.85 for intraobserver agreement on the total abnormality score and the entire checklist, respectively. IQ is negatively correlated with the total abnormality score (P < .001). Subjects with an IQ <70 have a significantly greater total score (P = .003) and a significantly greater score for 12 specific anomalies, including thinning of the corpus callosum (P = .001) and abnormalities of the lateral ventricles.

CONCLUSION

Mental retardation is associated with demonstrable brain anomalies, particularly thinning of the corpus callosum and ventricular abnormalities, and with a high total abnormality score. Greater levels of brain anomalies are associated with greater levels of mental retardation as evidenced by IQ.

Predicting the costs of managing patients with chronic obstructive pulmonary disease

The economic consequences of chronic obstructive pulmonary disease (COPD) are considerable, although the factors that best predict costs are largely unknown. This study used a population-based cohort to identify the clinical factors during an index year that were most predictive of increased direct medical costs in the subsequent year, and to develop a predictive model that described the cost variations in COPD. The medical records of 2116 patients enrolled in one regional health system who had COPD and health-care resource utilisation data for 1998 and 1999, were abstracted for information about symptoms, smoking history, chronic illnesses, and pulmonary function data. All inpatient, outpatient and pharmacy utilisation data for each subject for 1999 were extracted from the database. Total costs for each individual were transformed to a log scale. Potential causes of cost variability (predictor variables) were defined and classified into sets (or domains). Multiple linear regression models were fitted for each domain. The study demonstrated that severity of airflow obstruction, as assessed by FEV(1)% predicted, is a significant but weak predictor of future health-care resource utilisation-prior hospitalisation and home oxygen use, the presence of comorbid conditions and symptoms of dyspnoea are better predictors of costs. Those interested in the economic benefits of new COPD treatments and disease management programs need to carefully account for these factors.

First hundred cases of variant Creutzfeldt-Jakob disease: retrospective case note review of early psychiatric and neurological features

OBJECTIVE

To describe the early psychiatric and neurological features of variant Creutzfeldt-Jakob disease.

DESIGN

Cohort study.

SETTING

National surveillance system for Creutzfeldt-Jakob disease in the United Kingdom.

PARTICIPANTS

The first 100 cases of variant Creutzfeldt-Jakob disease identified in the United Kingdom.

MAIN OUTCOME MEASURES

The timing and nature of early psychiatric and neurological symptoms in variant Creutzfeldt-Jakob disease.

RESULTS

The early stages of variant Creutzfeldt-Jakob disease are dominated by psychiatric symptoms, but neurological symptoms precede psychiatric symptoms in 15% of cases and are present in combination with psychiatric symptoms in 22% of cases from the onset of disease. Common early psychiatric features include dysphoria, withdrawal, anxiety, insomnia, and loss of interest. No common early neurological features exist, but a significant proportion of patients do exhibit neurological symptoms within 4 months of clinical onset, including poor memory, pain, sensory symptoms, unsteadiness of gait, and dysarthria.

CONCLUSIONS

Although the diagnosis of variant Creutzfeldt-Jakob disease may be impossible in the early stages of the illness, particular combinations of psychiatric and neurological features may allow early diagnosis in an appreciable proportion of patients.

Leukoencephalopathy after CNS prophylaxis for acute lymphoblastic leukaemia

A 16 year old boy with epilepsy and learning difficulties is reported. At 3 years of age he was diagnosed with common acute lymphoblastic leukaemia, and received therapy according to the UK protocol, UKALL VIII. This included prophylactic CNS radiotherapy and chemotherapy. He did not develop CNS leukaemia, and complete remission was achieved. At age 7, he began to experience lethargy and learning difficulties, especially problems with hand-writing, concentration and memory. Furthermore, he began experiencing atypical absence seizures, which were provoked by concentration at times of tiredness. EEG showed bilateral non-specific abnormalities, with some epileptiform features. Over the following 9 years, several anti-epileptic drugs were prescribed. Although with the changes in therapy initial remissions have been achieved, the seizures have, each time, continued to relapse. At age 12, EEG was very abnormal, showing frequent generalized slow or sharp waves. At age 13, MRI revealed multiple discrete small high-intensity lesions in the subcortical white matter of both hemispheres. Problems with lethargy, concentration and memory persist and although multiple anti-epileptic drugs have been prescribed, seizures continue to occur almost daily.