Ben Ong

Are There Subgroups within the Autistic Spectrum? A Cluster Analysis of a Group of Children with Autistic Spectrum Disorders

Comprehensive data on the developmental history and current behaviours of a large sample of high-functioning individuals with diagnoses of autism, Aspergers syndrome, or other related disorder were collected via parent interviews. This provided the basis for a taxonomic analysis to search for subgroups. Most participants also completed theory of mind tasks. Three clusters or subgroups were obtained; these differed on theory of mind performance and on verbal abilities. Although subgroups were identified which bore some relationship to clinical differentiation of autistic, Asperger syndrome, and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) cases, the nature of the differences between them appeared strongly related to ability variables. Examination of the kinds of behaviours that differentiated the groups suggested that a spectrum of autistic disorders on which children differ primarily in term of degrees of social and cognitive impairments could explain the findings.

Early intervention for mild cognitive impairment: a randomised controlled trial

Background: Positive effects are reported for memory training for healthy older adults, and yet there is limited information about the benefit of cognitive intervention for older adults with increasing memory difficulties—mild cognitive impairment. Objective: To investigate the usefulness of an early cognitive intervention for the memory difficulties experienced by people with amnestic mild cognitive impairment. Methods: Using a randomised control design, 52 participants with amnestic mild cognitive impairment and their family partners were randomly assigned to a cognitive intervention (memory rehabilitation group) or waitlist (control group). Participants were assessed on primary measures of everyday memory (prospective memory) and memory strategies at 2 weeks’ and 4 months’ follow-up; secondary measures of contentment with memory and the family participants’ knowledge of memory strategies were also assessed. Results: Everyday memory, measured by performance on prospective memory tasks, significantly improved following intervention, although self-appraisal of everyday memory did not demonstrate a similar intervention effect. Knowledge and use of memory strategies also significantly increased following intervention. Furthermore, family knowledge of memory strategies increased following intervention. There was a strong trend towards improvement in contentment with memory immediately following intervention, but this effect was not significant. Conclusions: Early intervention for memory difficulties in amnestic mild cognitive impairment, using cognitive rehabilitation in compensatory strategies, can assist in minimising everyday memory failures as evaluated by performance on prospective memory tasks and knowledge of memory strategies.

The role of the family for behavioral outcome in children and adolescents following traumatic brain injury.

This study assessed the behavioral outcome of 51 children with traumatic brain injury (TBI) up to 2 years following injury. Children with severe injuries, but not those with mild or moderate injuries, were reported by parents to have a greater incidence of behavior problems following TBI. Regression analyses indicated that the presence of a partner for the primary caregiver of the child and the acute emotional reaction of the parent to the injury were both predictive of child behavioral outcome, although not by 2-year follow-up. These findings suggest that parental coping resources may impact on the development of child behavioral sequelae following TBI, emphasizing the role of the family in the childs response and the importance of supportive intervention.

Effect of age on forward and backward span tasks

The central executive component of working memory has been argued to play an important role in the performance of span tasks, particularly backward span. Age-related decline in central executive function has also been reported, and yet there have been inconsistent findings to indicate that with increasing age, the discrepancy between forward and backward span increases. A secondary analysis of the Wechsler Memory Scale-Third Edition standardization sample (N = 1030) was performed to investigate this relationship. It was hypothesized on the basis of past research indicating an age-related decline in central executive performance, that backward digit and spatial span performance would decrease at a greater rate than forward span performance. However, the results indicated that the rate of age-related performance decline was equivalent for both measures. It is proposed that both forward and backward span tasks recruit central executive resources for successful task performance.

Delayed Language Onset as a Predictor of Clinical Symptoms in Pervasive Developmental Disorders.

DSM-IV states that Asperger Disorder may be distinguished from Autistic Disorder by a lack of a delay in early language development. The aim of this study was to establish whether the presence or absence of early language delay would predict autistic symptomatology in children diagnosed with a PDD/autism spectrum disorder. Forty-six language-delayed and 62 normal language onset individuals (M age 11 years) were compared on ICD-10 research criteria and DSM-IV criteria, receptive language, and developmental history variables. Retrospective data were also obtained to determine whether language onset predicted autism symptomatology when young (<6 years). We found that early language delay predicts more autistic symptomatology when young, but not at an older age. Early language delay is also associated with developmental motor milestone delays and lower receptive language abilities. The results question the use of early language delay as a valid discriminating variable between PDD subgroups.

Measuring executive dysfunction in an acute rehabilitation setting: Using the dysexecutive questionnaire (DEX)

It is recognized that existing neuropsychological measures of executive dysfunction lack adequate sensitivity and selectivity. While attempts have been made to develop improved measures, these have not yet been of great value to those who need to accurately identify executive deficits in a clinical setting. Several behavioral rating scales have been developed for this reason, including the 20-item Dysexecutive Questionnaire (DEX), which forms part of the Behavioral Assessment of the Dysexecutive Syndrome (BADS) test battery. To investigate the ability of the DEX to identify executive dysfunction in an acute rehabilitation setting, the BADS was administered to 64 persons who had sustained traumatic brain injury. It was found to be almost as sensitive to executive dysfunction, as measured by the total score obtained on the BADS battery, as an extended 65-item version of the scale, when completed by either the occupational therapist or clinical neuropsychologist working with each patient. Family members and the patient themselves provided, as expected, less accurate information. Our results indicate that the DEX can be used with some confidence as a screening instrument to identify executive dysfunction in an acute rehabilitation setting, provided it is completed by professional personnel, trained to be sensitive to the cognitive and behavioral concomitants of this disorder.

Assessment of executive dysfunction following traumatic brain injury: Comparison of the BADS with other clinical neuropsychological measures

Traditional neuropsychological measures of executive dysfunction (ED) are widely believed to lack adequate sensitivity and selectivity. This may indicate that existing measures are poorly designed and constructed, although an alternative explanation is that executive cognition is multifactorial, such that its assessment necessarily requires administration of multiple measures. This possibility led to the development of a test battery, the Behavioural Assessment of the Dysexecutive Syndrome (BADS). To investigate the sensitivity of the BADS to ED, it and various other measures of ED were administered to 64 persons who had sustained traumatic brain injury. The treating clinical neuropsychologist and occupational therapist for each participant also completed a behavioural rating scale, the Dysexecutive Questionnaire (DEX). Four factors were found to underlie scores on the neuropsychological measures, but few tests were sufficiently powerful to make a significant unique contribution to predicting scores on the DEX. This confirms that multiple tests, drawn from both the BADS and other sources, may be necessary to detect ED in a clinical population.

DEMOGRAPHIC INFLUENCES ON BASELINE AND DERIVED SCORES FROM THE TRAIL MAKING TEST IN HEALTHY OLDER AUSTRALIAN ADULTS

Normative data from 363 community-dwelling older adults (60–89 years) is presented in relation to performance on the Trail Making Test. Age and years of education were identified as significantly impacting on performance. Therefore, data are presented for four separate age groups (60–69; 70–74; 75–79; 80–89) and two different lengths of education. In addition to data for Trails A and B, information is provided for the difference and ratio scores, which are increasingly used by clinicians to interpret executive function.

Elaborated spaced-retrieval and prospective memory in mild Alzheimer's disease

Prospective memory, or the timely remembering of a planned action, is conceptualised as a cognitive process demanding episodic memory and executive attention. Impairments in these skills are characteristic of the cognitive decline in early Alzheimers disease, providing an expectation of prominent prospective memory difficulties in this population, and yet surprisingly, memory performance in early Alzheimers disease has rarely been evaluated within a prospective memory framework. In a preliminary study we demonstrated that older adults with early Alzheimers disease (n = 14), as compared to healthy older adults (n = 14), were significantly impaired in a simple experimental paradigm of prospective remembering (a text-reading task). In a subsequent intervention study, we investigated the efficacy of spaced-retrieval for improving the prospective remembering performance of older adults with early Alzheimers disease (n = 16) compared to healthy older adults (n = 16) under two learning conditions: a spaced-retrieval technique alone or spaced-retrieval combined with elaborated encoding of task. The majority of the Alzheimers disease group (63%) demonstrated benefit in prospective remembering in the combined condition as compared to spaced-retrieval alone. Participants with Alzheimers disease who demonstrated better executive attention (Trail Making – set-shifting) and/or better retrospective memory (Hopkins Verbal Learning Test–Revised – recognition) were more successful in the combined learning condition.

Learning and memory in amnestic mild cognitive impairment: Contribution of working memory

In addition to deficits in delayed recall, recent research suggests that participants with amnestic mild cognitive impairment (aMCI) demonstrate diminished use of strategic encoding strategies during learning. Few studies have explored the cognitive mechanisms underlying this deficit. The aim of this study was to investigate in aMCI whether components of working memory (executive attention--attention set-shifting, dividing and focusing attention; and episodic buffer functions--strategic retrieval and manipulation of information) predict strategic encoding strategies during learning (semantic clustering). Thirty-three participants with aMCI and 33 healthy older adults (HOA) were administered neuropsychological tests assessing word-list learning and working memory. The aMCI group demonstrated significant impairment in acquisition, retrieval of information, and decreased use of semantic clustering strategies. Use of semantic clustering in the aMCI group was not predicted by measures of executive attention or phonemic verbal fluency, but was predicted by semantic verbal fluency performance. In the HOA group, semantic clustering was strongly related to semantic verbal fluency. These findings suggest that in aMCI, diminished strategic encoding strategies during learning (semantic clustering) is selectively related to the strategic function of the episodic buffer, but only when in interaction with the manipulation and retrieval of semantic associations.