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Biomedical subjects

M Prior

Publications and source records attributed to M Prior.

At least 55 records · Page 3Linked to original sources
PubMed1996

Implicit redundant-targets effect in visual extinction.

Patients with left visual extinction as a result of unilateral right hemisphere damage were tested on a redundant-targets effect paradigm (RTE). LED-generated brief flashes were lateralized either to the left or to the right visual hemifield or presented bilaterally. Subjects were asked to press a key as fast as possible following either unilateral or bilateral stimuli and immediately afterwards to report on the number of stimuli presented. As previously found in normal subjects, bilateral stimuli were responded to faster than unilateral ones, and this was evidence of a RTE. The main thrust of this study was that extinction patients showed a RTE not only for correctly perceived bilateral stimuli but also in trials in which they extinguished the stimulus on the field contralateral to the lesion. This result is compatible with a preserved processing of the extinguished input at least up to the stage at which it may interact with the input from the normal side to yield a speeded motor response. Interestingly, the implicit redundancy gain of extinction patients was found to fit a coactivation (i.e. neural) rather than a probabilistic model.

Aged↗
PubMed1996

Input and response determinants of visual extinction: a case study.

We have studied a patient, CZ, with contralateral visual extinction due to a large ischaemic frontal-parietal-temporal lesion in the right hemisphere. We found that manipulation of intensity of the visual stimulus had little effect while an increase in eccentricity substantially increased extinction rate. An important factor was represented by the hemifield of stimulus presentation: when double stimuli were presented to the contralesional (left) hemifield, the leftmost stimulus was consistently extinguished while when stimuli were presented to the ipsilesional (right) hemifield, extinction was absent. Such effect was specific to hemifield rather than to head- and trunk-defined hemispace. Manipulation of response-related variables affected extinction to a large extent: In particular, the use of nonverbal responses diminished extinction considerably. This suggests that an important component of extinction may be represented by an impaired access of visual information to the left hemisphere. Finally, the RT results confirmed previous evidence of an ipsilesional attentional bias favouring the rightmost stimuli both in the contralesional and in the ipsilesional hemifield.

Brain Ischemia↗
PubMed1996

Comparison of clinical symptoms in autism and Asperger's disorder.

OBJECTIVE: To determine what clinical symptoms clinicians have been using to distinguish between Asperger's disorder (AsD) and autistic disorder (AD). METHOD: Parents of children and adolescents with high-functioning AD (n = 48) and AsD (n = 69) were given a structured interview based on DSM-III-R and ICD-10 diagnostic criteria. Information regarding early and current symptom presentation and family, developmental, and verbal mental age information were collected. Logistic regression analyses were conducted to determine which variables best predicted clinician's diagnosis. RESULTS: A number of clinical variables predicted diagnosis. Delayed language onset was the only variable of the family and developmental variables that predicted diagnosis. The AsD group was also significantly higher than the AD group in verbal mental age. CONCLUSION: Clinicians appear to be diagnosing AsD and AD on the basis of published research and case study accounts. The findings question whether DSM-IV and ICD-10 criteria adequately describe the AsD individual, particularly in the communication domain.

Adolescent↗
PubMed1996

Reading disabilities with and without behaviour problems at 7-8 years: prediction from longitudinal data from infancy to 6 years.

Seven-year-old children with reading disabilities (RD-only), behaviour problems (BP-only), both conditions (RD-BP) and neither condition (Comparison) were compared on indices including temperament and behaviour, gathered in five periods between infancy and 6 years of age. The RD-BP group differed clearly from the RD-only group from infancy onwards. This comorbid group was similar to the BP-only group, while the RD-only group was similar to the Comparison group, until school age. The gender composition of the two RD groups differed, and the RD-BP boys showed the most problematic characteristics. The findings indicate different developmental pathways for "pure' RD children and those with comorbid BPs.

Attention Deficit Disorder with Hyperactivity↗
PubMed1995

Visual attention orienting in liver cirrhosis without overt hepatic encephalopathy.

The attention system in patients with liver cirrhosis has not yet been fully investigated. We therefore studied visual attention orienting in cirrhotic patients without overt hepatic encephalopathy. Seventy cirrhotic patients without overt hepatic encephalopathy (aged 57 +/- 10 yr., mean +/- s.d.) and 55 controls (aged 49 +/- 12 yr.) were enrolled. Visual attention orienting was evaluated by a computerized neuropsychological test. The Reitan A test, commonly used to detect subclinical hepatic encephalopathy, was used to evaluate mental performance. Psychometric test scores were reduced in cirrhotics compared to controls (attention test: neutral condition = 495 +/- 149 vs. 401 +/- 98 msec; valid condition = 434 +/- 110 vs. 398 +/- 84 msec; invalid condition = 485 +/- 146 vs. 392 +/- 110 msec; p < 0.001; Reitan A test = 52 +/- 20 vs. 35 +/- 11 sec., p < 0.001). The attention effect of the cue was found both in controls and cirrhotics; however, it was significantly higher in cirrhotics than in controls (61 +/- 111 vs. 33 +/- 41 msec; p < 0.002). The attention effect was directly correlated with Reitan A test (r = 0.23, p = 0.05) in cirrhotics. In conclusion, in cirrhotic patients without overt hepatic encephalopathy, visual attention orienting was present and focusing to an indexed location had a higher effect on reaction time compared to controls, possibly because of reduced basal arousal.

Aging↗
PubMed1995

Comparison of Asperger syndrome and high-functioning autistic children on a test of motor impairment.

Compared the motor impairment levels of Asperger syndrome and high functioning autistic children using a standardized test, the Test of Motor Impairment-Henderson Revision. The two groups did not differ on either total or subscale impairment scores. Intelligence level was negatively correlated with motor impairment although the relationship was mostly accounted for by the Asperger children. There was considerable variability within both clinical groups but 50% of Asperger children and 67% of autistic children showed a clinically significant level of motor impairment. Results offer no support for clumsiness as a diagnostically differentiating feature of these disorders.

Adolescent↗
PubMed1995

Neuropsychological deficit and academic performance in children and adolescents following traumatic brain injury.

Evaluated the utility of neuropsychological testing in predicting academic outcome in children 1 year following traumatic brain injury (TBI). Fifty-one school age children who were admitted to hospital after TBI were assessed with a battery of neuropsychological measures at 3 months postinjury. Academic achievement was assessed at 3 and 12 months postinjury. The neuropsychological battery included intelligence testing and measures of memory, learning, and speed of information processing. Academic outcome was assessed in terms of post-TBI changes in reading, spelling, and arithmetic; changes in teacher ratings of school performance; and change in school placement. According to logistic regression analysis, change in placement from regular to special education at 1-year post-TBI was predicted by injury severity and by neuropsychological performance at 3 months post-TBI. Findings suggest that neuropsychological testing is useful in identifying children with special educational needs subsequent to TBI.

Achievement↗
PubMed1995

Temperament and stress resilience in school-age children: a within-families study.

OBJECTIVE: Stress resilience was assessed in 81 school-age children, from within 32 families acknowledging severe psychosocial stress. Resilient and nonresilient children, identified via competence and behavior disorder measures from school and home, were compared. METHOD: Parents and teachers completed questionnaires and rating scales, and children were observed and assessed at home on attributes of temperament, self-esteem, ability, gender, and mother-child warmth. RESULTS: Individual differences in child and family attributes that were predictive of competent child functioning varied according to the outcome measure used. Teachers' ratings of positive temperament (low emotional reactivity, high social engagement) best discriminated children showing resilience on all indicators, i.e., behavioral and social competence both at home and at school, with maternal warmth and the number of adverse life events the child had recently experienced also contributing. Level of maternal stress and individual differences in child intelligence were related to academic adjustment, but the child's age, sex, ability, and self-concept were not significant discriminators of behavioral adjustment. CONCLUSIONS: The findings emphasize the salience of a positive temperament as a resilience factor as well as the need to consider different estimates and contexts in assessing resilience for children growing up in stressful situations.

Adaptation, Psychological↗
PubMed1995

The development of patterns of stable, transient, and school-age onset aggressive behavior in young children.

OBJECTIVE: To examine the development of patterns of aggressive behavior in children from the age of 2 to 8 years. METHOD: Children with early histories of aggressive behavior were selected from a community sample of 2,400 infants participating in a longitudinal study. The sample was divided into four groups: children with stable aggressive behavior, those with transient aggression, those with aggression only after age 5 years (late onset), and a comparison group of nonaggressive children. RESULTS: Children with stable aggressive behavior were characterized by a difficult temperament, hostile sibling interactions, maternal perception of the child as difficult, and harsher child-rearing practices. Children whose early aggression decreased over time and those who became aggressive only after entering school could not be reliably classified with the selected family variables. Teacher ratings of temperament factors of task orientation and reactivity and ability ratings correctly classified 74% of children whose aggression began at school-age. CONCLUSIONS: Children with persistent aggressive behavior differed from those who improved, predominantly in terms of symptom severity. Problems with aggression can be identified early in development, and a significant proportion of aggressive children are at risk for continuing social and scholastic difficulties. Knowledge of associated factors may play an important role in prevention.

Age of Onset↗
PubMed1995

Micro- and macrocirculatory, and biohumoral changes after a month of physical exercise in patients with intermittent claudication.

We studied 15 subjects with intermittent claudication, classed as stage II according to Leriche-Fontaine. The patients were subjected to laser Doppler flowmetry, strain gauge plethysmography, Doppler velocimetry, and blood sampling, in basal conditions and after one month of physical training. Symptom-free walking distance at the end of the training period showed a significant increase, while there was no major change in maximal walking distance or the Windsor index. Laser Doppler flowmetry showed no significant change in cutaneous blood flow at rest, after the month of physical training. On the other hand, strain gauge plethysmography showed a significant decrease in rest flow at the end of the training period, while peak flow of postischemic hyperemia did not change appreciably. Biohumoral evaluations showed a significant decrease of white blood cell count, triglycerides and uric acid. Platelet count, prothrombin time, aPTT and plasminogen were unchanged. On the other hand, we recorded a small, but significant, rise of fibrinogen. Our study confirmed the importance of scheduled physical activity in the patient with intermittent claudication, showing that clinical improvement is not accompanied by an increase in the circulatory reserve. The unchanged levels of plasminogen suggest that the fibrinolytic activity does not vary significantly after a course of physical exercise.

Aged↗
PubMed1995

Lipoprotein(a) and general risk factors in patients with angiographically assessed peripheral arterial disease.

High lipoprotein(a) [Lp(a)] has been observed in patients with ischemic heart disease and cerebrovascular disease. Lp(a) is actually thought to be an independent risk factor for coronary disease. We therefore carried out a case-control study, evaluating plasma Lp(a) in 61 patients with angiographically documented peripheral arterial disease (PAD) and in 61 age- and sex-matched patients with no cardiovascular disease. General risk factors for vascular disease were also taken into account. Lp(a) was significantly higher in patients than controls (257.0 +/- 34.8 vs 146.5 +/- 23.5 mg/l p < 0.05), as were cigarette smoking, diabetes, cholesterolemia, fibrinogenemia and the waist-to-hip circumference ratio. Stepwise logistic regression analysis showed that, in addition to cigarette smoking, diabetes, cholesterol and fibrinogen, Lp(a) is a significant independent risk indicator for PAD. This result suggests that high plasma Lp(a) is associated with enhanced risk of PAD and must therefore be evaluated alongside traditional risk factors.

Adult↗
PubMed1994

Can autistic children distinguish lies from jokes? A second look at second-order belief attribution.

Previous studies show that autistic children fail tests of second-order belief attribution. They also fail tests of lying and deception. The present study used Leekam's (1988) joke-lie distinction task to test (a) understanding of second-order mental states (intention and belief) and (b) the ability to judge these acts as lies or jokes. Seventeen normal and 16 autistic children took part. Eight of the autistic children had previously passed a test of first-order false belief. Results showed that six autistic subjects (37.5%), all of whom are false belief "passers", gave consistently correct answers to second-order mental state questions. Neither normal nor autistic children found second-order intention easier than second-order belief. However, normal children found the ability to judge another person's mental state easier than labelling whether the person was lying or joking, supporting previous evidence. In contrast, there was no difference in these two judgements for autistic children. Overall these results qualify previous evidence by showing that autistic children can use second-order reasoning and can distinguish lies from jokes. Observational data on these children, however, suggest that their competence on the comprehension of these hypothetical situations was not matched by an ability to use lying and joking in real life. Methodological, language and diagnostic factors are discussed as providing possible explanations for the results.

Adolescent↗
PubMed1993

Sex differences in psychological adjustment from infancy to 8 years.

The objective of this study was to explore sex differences in development from infancy to 8 years of age in a community sample. Measures of biological, social, interactive, and parental functioning as well as teacher reports were obtained. There were minimal differences in infancy, but major psychosocial differences emerged with increasing age. In the biological sphere boys were disadvantaged only in ratings of language and motor skills at 3 to 4 years old. They showed greater temperamental "difficulty" and low persistence factor scores from 5 years onward. Boys were significantly more likely to have problems with adaptive behavior and social competence and to show behavior problems of the hyperactive and aggressive type, as rated by mothers. Parent and family functioning measures did not differentiate between the sexes. Teachers rated boys as having more problems in academic and behavioral domains the first 3 years of school. Path analyses combining data sets gathered when the children were 3 to 8 years old demonstrated the differential courses of development for boys and girls although temperamental flexibility was the best predictor of behavioral adjustment for both sexes. A social learning explanation of the increased incidence of problems among males is supported, although biological influences are not ruled out.

Adaptation, Psychological↗
PubMed1993

Precursors of hyperactivity and aggression.

OBJECTIVE: This study investigated the early characteristics of children who at 8 years old were hyperactive, aggressive, or both, to clarify the etiology of these disorders. METHOD: Prospective data from infancy to 8 years on children who were hyperactive (N = 65), aggressive (N = 57), or both (N = 60) at 8 years were compared with those on a normal comparison group (N = 70). Variables included ratings of temperament, behavior, school performance, and socioeconomic and life stress indices. RESULTS: The two aggressive groups, particularly the hyperactive-aggressive group, were more difficult in temperament and behavior from infancy and had less optimal environments. In contrast, the "pure" hyperactive group showed more problems than did the comparison group only from 3 to 4 years on. All three clinical groups had poorer academic performance than did the controls. CONCLUSIONS: The findings are consistent with a transactional model of development in which aggression (with or without hyperactivity) emerges when difficultness in infancy interacts with a stressed environment. Hyperactivity, when unassociated with aggression, may emerge later from poor self-regulation when faced with societal, especially school, demands. The pattern of group differences found suggest that risk indicators for specific patterns of later maladjustment may be identifiable for early intervention.

Adolescent↗
PubMed1993

Effects of therapeutic doses of salbutamol alone and combined with beclomethasone dipropionate on airway responsiveness and cyclic AMP plasma levels in asthmatic patients.

Twelve asthmatic patients received by inhalation for 2 weeks, in a double-blind, cross-over design, beclomethasone dipropionate (BDP; 600 micrograms/day) plus salbutamol (S; 900 micrograms/day), or S (900 micrograms/day) alone. Before and after each treatment course the subjects received intravenous cumulative doses of S up to 200 micrograms. In basal conditions and immediately before the next dose forced expiratory volume in 1 s (FEV1) and plasma cyclic AMP (cAMP) were measured. BDP+S treatment increased FEV1 basal values (p < 0.05) whereas inhaled S resulted in unsignificant improvement of ventilatory parameters. The slopes of the dose-response curves of FEV1 and plasma cAMP to intravenous S were unaffected by the two treatment courses. Our results suggest that DBP+S, differently from S alone, improves ventilatory function in asthmatic patients and that neither S nor S+BDP seem to affect adrenergic function.

Administration, Inhalation↗