Multivariate genetic analysis of cognitive abilities in an adolescent twin sample

The sources of covariation among cognitive measures of Inspection Time, Choice Reaction Time, Delayed Response Speed and Accuracy, and IQ were examined in a classical twin design that included 245 monozygotic (MZ) and 298 dizygotic (DZ) twin pairs. Results indicated that a factor model comprising additive genetic and unique environmental effects was the most parsimonious. In this model, a general genetic cognitive factor emerged with factor loadings ranging from 0.28 to 0.64. Three other genetic factors explained the remaining genetic covariation between various speed and Delayed Response measures with IQ. However, a large proportion of the genetic variation in verbal (54%) and performance (25%) IQ was unrelated to these lower order cognitive measures. The independent genetic IQ variation may reflect information processes not captured by the elementary cognitive tasks, Inspection Time and Choice Reaction Time, nor our working memory task, Delayed Response. Unique environmental effects were mostly nonoverlapping, and partly represented test measurement error.

The roles of depression and anxiety in the understanding and treatment of Obstructive Sleep Apnea Syndrome

Obstructive Sleep Apnea Syndrome (OSAS) is a debilitating condition stemming from disruption to the respiratory system during sleep. At present, the nature of the relationship between OSAS and mood, specifically depression and anxiety, is still unclear. The purpose of this paper is to shed some light on this relationship. PsycINFO was used to locate relevant papers on this topic. This literature search formed the basis of our investigation. Results showed that the anxiety and depression methodology is weak. It is now clear that there is an urgent need to better understand the roles of anxiety and depression in OSAS. For example, the research literature suggests that depression and anxiety covary with OSAS. However, because of methodological issues, such as difficulties involved in diagnosis and the use of inappropriate instruments, this conclusion remains tenuous. Future directions are discussed. (C) 2004 Elsevier Ltd. All rights reserved.

Familial influence on offspring gambling: a cognitive mechanism for transmission of gambling behavior in families

Background. The problem-gambling literature has identified a range of individual, cognitive, behavioral and emotional factors as playing important roles in the development, maintenance and treatment of problem gambling. However, familial factors have often been neglected. The current study aims to investigate the possible influence of parental factors on offspring gambling behavior. Method. A total of 189 families (546 individuals) completed several questionnaires including the South Oaks Gambling Screen (SOGS) and the Gambling Related Cognition Scale (GRCS). The relationships were examined using Pearson product-moment correlations and structural equation modeling (SEM) analyses. Results. Results showed that generally parents' (especially fathers') gambling cognitions and gambling behaviors positively correlated with offspring gambling behaviors and cognitions. However, SEM analyses showed that although parental gambling behavior was directly related to offspring gambling behavior, parental cognitions were not related to offspring gambling behavior directly but indirectly via offspring cognitions. Conclusion. The findings show that the influence of parental gambling cognition on offspring gambling behavior is indirect and via offspring cognitions. The results suggest a possible cognitive mechanism of transmission of gambling behavior in the family from one generation to the next.

A cognitive model of binge drinking: The influence of alcohol expectancies and drinking refusal self-efficacy

While binge drinking-episodic or irregular consumption of excessive amounts of alcohol-is recognised as a serious problem affecting our youth, to date there has been a lack of psychological theory and thus theoretically driven research into this problem. The current paper develops a cognitive model using the key constructs of alcohol expectancies (AEs) and drinking refusal self-efficacy (DRSE) to explain the acquisition and maintenance of binge drinking. It is suggested that the four combinations of the AE and DRSE can explain the four drinking styles. These are normal/social drinkers, binge drinkers, regular heavy drinkers, and problem drinkers or alcoholics. Since AE and DRSE are cognitive constructs and therefore modifiable, the cognitive model can thus facilitate the design of intervention and-prevention strategies for binge drinking. (C) 2003 Elsevier Ltd. All rights reserved.

The mismatch negativity (MMN) response to complex tones and spoken words in individuals with aphasia

Background: The mismatch negativity (MMN) is a fronto-centrally distributed event-related potential (ERP) that is elicited by any discriminable auditory change. It is an ideal neurophysiological tool for measuring the auditory processing skills of individuals with aphasia because it can be elicited even in the absence of attention. Previous MMN studies have shown that acoustic processing of tone or pitch deviance is relatively preserved in aphasia, whereas the basic acoustic processing of speech stimuli can be impaired (e.g., auditory discrimination). However, no MMN study has yet investigated the higher levels of auditory processing, such as language-specific phonological and/or lexical processing, in individuals with aphasia. Aims: The aim of the current study was to investigate the MMN response of normal and language-disordered subjects to tone stimuli and speech stimuli that incorporate the basic auditory processing (acoustic, acoustic-phonetic) levels of non-speech and speech sound processing, and also the language-specific phonological and lexical levels of spoken word processing. Furthermore, this study aimed to correlate the aphasic MMN data with language performance on a variety of tasks specifically targeted at the different levels of spoken word processing. Methods M Procedures: Six adults with aphasia (71.7 years +/- 3.0) and six healthy age-, gender-, and education-matched controls (72.2 years +/- 5.4) participated in the study. All subjects were right-handed and native speakers of English. Each subject was presented with complex harmonic tone stimuli, differing in pitch or duration, and consonant-vowel (CV) speech stimuli (non-word /de:/versus real world/deI/). The probability of the deviant for each tone or speech contrast was 10%. The subjects were also presented with the same stimuli in behavioural discrimination tasks, and were administered a language assessment battery to measure their auditory comprehension skills. Outcomes O Results: The aphasic subjects demonstrated attenuated MMN responses to complex tone duration deviance and to speech stimuli (words and non-words), and their responses to the frequency, duration, and real word deviant stimuli were found to strongly correlate with performance on the auditory comprehension section of the Western Aphasia Battery (WAB). Furthermore, deficits in attentional lexical decision skills demonstrated by the aphasic subjects correlated with a word-related enhancement demonstrated during the automatic MMN paradigm, providing evidence to support the word advantage effect, thought to reflect the activation of language-specific memory traces in the brain for words. Conclusions: These results indicate that the MMN may be used as a technique for investigating general and more specific auditory comprehension skills of individuals with aphasia, using speech and/or non-speech stimuli, independent of the individual's attention. The combined use of the objective MMN technique and current clinical language assessments may result in improved rehabilitative management of aphasic individuals.

Cognitive disorders and neurogenesis deficits in Huntington's disease mice are rescued by fluoxetine

Huntington's disease (HD) is a neurodegenerative disorder caused by an expanded CAG trinucleotide repeat encoding an extended polyglutamine tract in the huntingtin protein. Affected individuals display progressive motor, cognitive and psychiatric symptoms (including depression), leading to terminal decline. Given that transgenic HD mice have decreased hippocampal cell proliferation and that a deficit in neurogenesis has been postulated as an underlying cause of depression, we hypothesized that decreased hippocampal neurogenesis contributes to depressive symptoms and cognitive decline in HD. Fluoxetine, a serotonin-reuptake inhibitor commonly prescribed for the treatment of depression, is known to increase neurogenesis in the dentate gyrus of wild-type mouse hippocampus. Here we show that hippocampal-dependent cognitive and depressive-like behavioural symptoms occur in HD mice, and that the administration of fluoxetine produces a marked improvement in these deficits. Furthermore, fluoxetine was found to rescue deficits of neurogenesis and volume loss in the dentate gyrus of HD mice.

Neural pathways mediating bilateral interactions between the upper limbs

The ease with which we perform tasks such as opening the lid of a jar, in which the two hands execute quite different actions, belies the fact that there is a strong tendency for the movements of the upper limbs to be drawn systematically towards one another. Mirror movements, involuntary contractions during intended unilateral engagement of the opposite limb, are considered pathological, as they occur in association with specific disorders of the CNS. Yet they are also observed frequently in normally developing children, and motor irradiation, an increase in the excitability of the (opposite) homologous motor pathways when unimanual movements are performed, is a robust feature of the mature motor system. The systematic nature of the interactions that occur between the upper limbs has also given rise to the expectation that functional improvements in the control of a paretic limb may occur when movements are performed in a bimanual context. In spite of the ubiquitous nature of these phenomena, there is remarkably little consensus concerning the neural basis of their mediation. In the present review, consideration is given to the putative roles of uncrossed corticofugal fibers, branched bilateral corticomotoroneuronal projections, and segmental networks. The potential for bilateral interactions to occur in various brain regions including the primary motor cortex, the supplementary motor area, non-primary motor areas, the basal ganglia, and the cerebellum is also explored. This information may provide principled bases upon which to evaluate and develop task and deficit-specific programs of movement rehabilitation and therapy. (c) 2005 Elsevier B.V. All rights reserved.

The clinical effectiveness of a multisensory therapy on clients with developmental disability

Many clients in Hong Kong with developmental disabilities stay in mental hospitals because of mental disorders and behavioural problems. There is a need to identify strategies that promote psychological well-being and reduce problem behaviours in this group of clients. This study evaluates the impact of multisensory therapy on participants’ emotional state, level of relaxation, challenging behaviour, stereotypic self-stimulating behaviour (SSB) and adaptive behaviour (AB). Using an experimental design, 89 participants were recruited from a developmental disability unit in a hospital in Hong Kong and randomly assigned to either an experimental (n = 48) or a control group (n = 41). Multisensory therapy sessions (n = 36) were conducted with experimental group and activity sessions (n = 36) were conducted with controls for 12 weeks. Multisensory therapy promoted participants’ positive emotions and relaxation. However, there was no evidence that multisensory therapy was superior to activity therapy in reducing aggressive behaviour and stereotypic self-stimulating behaviour or promoting adaptive behaviour. The key variables that influence clients’ behaviours in the multisensory therapy may be related to the relationship with the carer, constant environment, relaxation and freedom from demands rather than sensory input. Multisensory therapy could be used to provide leisure and promote psychological well-being, rather than for reducing problem behaviour.

A randomised controlled trial of a CBT intervention for anxiety in children with Asperger syndrome

Background: The aim of the study was to evaluate the effectiveness of a brief CBT intervention for anxiety with children diagnosed with Asperger syndrome (AS). A second interest was to evaluate whether more intensive parent involvement would increase the child's ability to manage anxiety outside of the clinic setting. Methods: Seventy-one children aged ten to twelve years were recruited to participate in the anxiety programme. All children were diagnosed with AS and the presence of anxiety symptoms was accepted on parent report via brief interview. Children were randomly assigned to one of three conditions: intervention for child only, intervention for child and parent, wait-list control. Results: The two intervention groups demonstrated significant decreases in parent-reported anxiety symptoms at follow-up and a significant increase in the child's ability to generate positive strategies in an anxiety-provoking situation. There were a number of significant differences between the two interventions to suggest parent involvement as beneficial. Conclusions: The sample of children with AS in this study presented with a profile of anxiety similar to a sample of clinically diagnosed anxious children. The intervention was endorsed by parents as a useful programme for children diagnosed with Asperger syndrome and exhibiting anxiety symptoms, and active parent involvement enhanced the usefulness of the programme. Limitations of the study and future research are discussed.

A review of awareness interventions in brain injury rehabilitation

Unawareness related to brain injury has implications for participation in rehabilitation, functional outcomes, and the emotional well-being of clients. Addressing disorders of awareness is an integral component of many rehabilitation programmes, and a review of the literature identified a range of awareness interventions that include holistic milieu-oriented neuropsychological programmes, psychotherapy, compensatory and facilitatory approaches, structured experiences, direct feedback, videotaped feedback, confrontational techniques, cognitive therapy, group therapy, game formats and behavioural intervention. These approaches are examined in terms of their theoretical bases and research evidence. A distinction is made between intervention approaches for unawareness due to neurocognitive factors and approaches for unawareness due to psychological factors. The socio-cultural context of unawareness is a third factor presented in a biopsychosocial framework to guide clinical decisions about awareness interventions. The ethical and methodological concerns associated with research on awareness interventions are discussed. The main considerations relate to the embedded nature of awareness interventions within rehabilitation programmes, the need for individually tailored interventions, differing responses according to the nature of unawareness, and the risk of eliciting emotional distress in some clients.

Objective and behavioural assessment of the emergence from post-traumatic amnesia (PTA)

Primary objective: To determine the profile of resolution of typical PTA behaviours and describe new learning and improvements in self-care during PTA. Research design: Prospective longitudinal study monitoring PTA status, functional learning and behaviours on a daily basis. Methods and procedures: Participants were 69 inpatients with traumatic brain injury who were in PTA. PTA was assessed using the Westmead or Oxford PTA assessments. Functional learning capability was assessed using a routine set of daily tasks and behaviour was assessed using an observational checklist. Data was analysed using descriptive statistics. Main outcomes and results: Challenging behaviours that are typically associated with PTA, such as agitation, aggression and wandering resolved in the early stages of PTA and incidence rates of these behaviours were less than 20%. Independence in self-care and bowel and bladder continence emerged later during resolution of PTA. New learning in functional situations was demonstrated by patients in PTA. Conclusions: It is feasible to begin active rehabilitation focused on functional skills-based learning with patients in the later stages of PTA. Formal assessment of typically observed behaviours during PTA may complement memory-based PTA assessments in determining emergence from PTA.

Cognitive modelling and the behaviour genetics of reading

While it is well known that reading is highly heritable, less has been understood about the bases of these genetic influences. In this paper, we review the research that we have been conducting in recent years to examine genetic and environmental influences on the particular reading processes specified in the dual-route cognitive model of reading. We argue that a detailed understanding of the role of genetic factors in reading acquisition requires the delineation and measurement of precise phenotypes, derived from well-articulated models of the reading process. We report evidence for independent genetic influences on the lexical and nonlexical reading processes represented in the dual-route model, based on studies of children with particular subtypes of dyslexia, and on univariate and multivariate genetic modelling of reading performance in the normally reading population.

Genome-wide scan of IQ finds significant linkage to a quantitative trait locus on 2q

A genome-wide linkage scan of 795 microsatellite markers (761 autosomal, 34 X chromosome) was performed on Multidimensional Aptitude Battery subtests and verbal, performance and full scale scores, the WAIS-R Digit Symbol subtest, and two word-recognition tests (Schonell Graded Word Reading Test, Cambridge Contextual Reading Test) highly predictive of IQ. The sample included 361 families comprising 2-5 siblings who ranged in age from 15.7 to 22.2 years; genotype, but not phenotype, data were available for 81% of parents. A variance components analysis which controlled for age and sex effects showed significant linkage for the Cambridge reading test and performance IQ to the same region on chromosome 2, with respective LOD scores of 4.15 and 3.68. Suggestive linkage (LOD score > 2.2) for various measures was further supported on chromosomes 6, 7, 11, 14, 21 and 22. Where location of linkage peaks converged for IQ subtests within the same scale, the overall scale score provided increased evidence for linkage to that region over any individual subtest. Association studies of candidate genes, particularly those involved in neural transmission and development, will be directed to genes located under the linkage peaks identified in this study.