Biomedical subjects

Scott Hall

Publications and source records attributed to Scott Hall.

10 recordsLinked to original sources

PubMed2006

3D pattern of brain abnormalities in Fragile X syndrome visualized using tensor-based morphometry.

Fragile X syndrome (FraX), a genetic neurodevelopmental disorder, results in impaired cognition with particular deficits in executive function and visuo-spatial skills. Here we report the first detailed 3D maps of the effects of the Fragile X mutation on brain structure, using tensor-based morphometry. TBM visualizes structural brain deficits automatically, without time-consuming specification of regions-of-interest. We compared 36 subjects with FraX (age: 14.66+/-1.58 S.D., 18 females/18 males), and 33 age-matched healthy controls (age: 14.67+/-2.2 S.D., 17 females/16 males), using high-dimensional elastic image registration. All 69 subjects' 3D T1-weighted brain MRIs were spatially deformed to match a high-resolution single-subject average MRI scan in ICBM space, whose geometry was optimized to produce a minimal deformation target. Maps of the local Jacobian determinant (expansion factor) were computed from the deformation fields. Statistical maps showed increased caudate (10% higher; p = 0.001) and lateral ventricle volumes (19% higher; p = 0.003), and trend-level parietal and temporal white matter excesses (10% higher locally; p = 0.04). In affected females, volume abnormalities correlated with reduction in systemically measured levels of the Fragile X mental retardation protein (FMRP; Spearman's r < -0.5 locally). Decreased FMRP correlated with ventricular expansion (p = 0.042; permutation test), and anterior cingulate tissue reductions (p = 0.0026; permutation test) supporting theories that FMRP is required for normal dendritic pruning in fronto-striatal-limbic pathways. No sex differences were found; findings were confirmed using traditional volumetric measures in regions of interest. Deficit patterns were replicated by performing statistics after logarithmic transformation, which may be more appropriate for tensor-valued data. Investigation of how these anomalies emerge over time will accelerate our understanding of FraX and its treatment.

Adult↗

PubMed2006

Social escape behaviors in children with fragile X syndrome.

Social escape behavior is a common behavioral feature of individuals with fragile X syndrome (fraX). In this observational study, we examined the effect of antecedent social and performance demands on problem behaviors in four conditions: face-to-face interview, silent reading, oral reading and a singing task. Results showed that problem behaviors were significantly more likely to occur during the interview and singing conditions. Higher levels of salivary cortisol were predictive of higher levels of fidgeting behavior and lower levels of eye contact in male participants. There were no associations between level of FMRP expression and social escape behaviors. These data suggest that specific antecedent biological and environmental factors evoke social escape behaviors in fragile X syndrome.

Adolescent↗

PubMed2006

Effects of social context on social interaction and self-injurious behavior in Cornelia de Lange syndrome.

Cornelia de Lange syndrome is reported to be associated with self-injurious behavior (SIB) and social avoidance. We used analog methodology to examine the effect of manipulating adult social contact on social communicative behaviors and SIB in 16 children with this syndrome. For 9 participants engagement behavior was related to levels of adult attention, and SIB showed significant variability across conditions for 3 participants. These findings indicate that SIB can be affected by environmental factors, even though it is thought to be part of the behavioral phenotype of Cornelia de Lange syndrome and suggest that individuals with this syndrome show socially motivated attention-soliciting behaviors. The implications for gene-environment interactions are discussed.

Child↗

PubMed2005

Effects of increasing task load on memory impairment in adults with Down syndrome.

The effect of increasing the number of stimuli to be recalled was investigated to evaluate whether sensitivity for memory impairment was enhanced in adults with Down syndrome when using higher task load. Three levels of load were compared across three groups of adults: those with cognitive deterioration, no cognitive deterioration over age 40, and no cognitive-deterioration under 40. The cognitive-deterioration group showed impaired performance in comparison to the no cognitive-deterioration-40+ group at all levels of task load, with performance declining over 4 years. The no cognitive-deterioration-40+ group showed no impairment in performance compared to no cognitive-deterioration-under 40 group, except when task load was high. Implications for identification of dementia and age-related cognitive change are discussed.

Adult↗

PubMed2003

Descriptive functional analysis of behavioral excesses shown by adults with Down syndrome and dementia.

OBJECTIVES: The study examined the hypothesis that a functional relationship exists between social environmental events and behavioral excesses in individuals with Down syndrome and dementia. DESIGN: A case-series design was employed (n = 4) using an direct observation-based descriptive functional assessment procedure. METHODS: Observations were conducted in the natural environments of four participants over periods ranging from 11 to 15.4 hours. Data were collected on non-verbal and verbal behavioral excesses, appropriate engagement and verbal interaction with others. Social environmental events observed including both staff and peer behavior. RESULTS: Analysis of co-occurrence for behavioral excesses and social environmental events indicated significant relationships for some behaviours consistent with operant reinforcement processes. Sequential analysis showed that changes in the probability of social contact occurred in the period directly preceding and following verbal behaviors. CONCLUSIONS: Results support the hypothesis that, consistent with literature for older adults with dementia in the general population, some behavioral excesses were functional in nature and not randomly occurring events. No relationship was found between appropriate engagement and staff contact. Evidence of the functional nature of target behavioral excesses indicates that behavioral interventions have potential for this client group.

Adult↗

PubMed2003

Phenomenology of self-restraint.

Self-restraint is often reported in individuals with mental retardation who show self-injurious behavior (SIB). In this study, the phenomenology and prevalence of self-restraint in individuals showing self-injury and wearing protective devices and those showing self-injury but not wearing protective devices were compared. A high prevalence of self-restraint in the whole sample of individuals showing self-injury was identified (67/88, 76.1%), and self-restraint was more prevalent in a group showing self-injury but not wearing protective devices (43/47, 91.5%) than in a group showing self-injury and wearing protective devices (24/41, 58.5%). Individuals not wearing protective devices showed a greater number of topographies of self-restraint than those who did wear them. Results are discussed with reference to the purely topographical definition of self-restraint employed and the potential equivalence of protective devices and self-restraint.

Adolescent↗

PubMed2003

Structural and environmental characteristics of stereotyped behaviors.

Structural and environmental characteristics of multiple topographies of stereotypic behaviors shown by 8 individuals with developmental disabilities are described. Analysis of structural characteristics show that the parameters of stereotyped behavior (percentage of time, bout length, and bout length variability) were highly correlated. Analysis of the influence of environmental variables indicated that topographies of stereotyped behaviors were more likely to occur under conditions of low stimulation and less likely during conditions involving social contact. Individuals whose stereotyped behaviors were less influenced by environmental factors were more likely to engage in them for greater periods of time. Results suggest that an examination of individual topographies of stereotyped behaviors and their structural and environmental characteristics may provide useful insights for understanding the origins of these behaviors.

Adolescent↗

PubMed2002

Self-injurious behavior, self-restraint, and compulsive behaviors in Cornelia de Lange syndrome.

Researchers have argued that individuals who show self-restraint are more likely to show self-injurious behavior (SIB) that is compulsive. Self-injurious behavior, self-restraint, and compulsive behaviors have been described as features of Cornelia de Lange syndrome. We examined whether individuals with this syndrome displaying SIB and self-restraint exhibit more compulsive behaviors than do those without SIB and self-restraint. Main caregivers of individuals with the syndrome completed questionnaires. A significant association was found between SIB and self-restraint, and those displaying both behaviors displayed significantly more compulsions than did those not exhibiting them. Findings extend the compulsive behavior theory and highlight areas for further research.

Adolescent↗

PubMed2002

Effects of environmental events on smiling and laughing behavior in Angelman syndrome.

Angelman syndrome is a neurogenetic disorder associated with unique behaviors and characteristics, including an unusually happy expression, inability to speak, ataxia, mental retardation, and abnormal EEG. Previous research has suggested that smiling and laughing behaviors in Angelman syndrome are inappropriate, excessive, and dissociated from contextual events. In the present study, the variability of smiling and laughing behaviors of 3 individuals with Angelman syndrome was examined across typical social contexts. Results indicate that laughing and smiling increased during social situations and occurred at low levels during non-social situations. The behaviors, therefore, did not occur totally inappropriately, as has been suggested. The findings illustrate the need to divert attention to the examination of environmental influences on purported phenotypic behavior in genetic syndromes.

Adolescent↗

PubMedDate not supplied

Coronary artery bypass grafting in a patient with Glanzmann's thrombasthenia.

Glanzmann's thrombasthenia is a platelet aggregation disorder resulting from a functional loss of platelet membrane glycoprotein IIb-IIIa. First described by Dr. Glanzmann in 1918, the disorder is characterized clinically by mucocutaneous bleeding and physiologically by absent platelet aggregation to collagen, epinephrine, and adenosine diphosphate stimulation. While there are multiple reports of patients with Glanzmann's thrombasthenia undergoing surgery, to our knowledge there has been no report of a patient with Glanzmann's undergoing coronary artery bypass grafting. We present the first such report of a patient who successfully underwent operative coronary artery revascularization, and offer suggestions for future management of these patients.

Aged↗