Biomedical subjects

Tom Manly

Publications and source records attributed to Tom Manly.

10 recordsLinked to original sources

PubMed2003

Facial expression recognition across the adult life span.

We report three experiments investigating the recognition of emotion from facial expressions across the adult life span. Increasing age produced a progressive reduction in the recognition of fear and, to a lesser extent, anger. In contrast, older participants showed no reduction in recognition of disgust, rather there was some evidence of an improvement. The results are discussed in terms of studies from the neuropsychological and functional imaging literature that indicate that separate brain regions may underlie the emotions fear and disgust. We suggest that the dissociable effects found for fear and disgust are consistent with the differential effects of ageing on brain regions involved in these emotions.

Adolescent↗

PubMed2003

Modulation of spatial attention in a child with developmental unilateral neglect.

Attentional neglect of left space is one of the most striking acquired neurological disorders of adulthood. Recent evidence indicates a link between left spatial neglect and general right-hemisphere impairments in sustained attention and alertness. Poor sustained attention and alertness is also a central feature of other disorders, particularly childhood attention-deficit-hyperactivity disorder (ADHD). Here we present the case of a 7-year-old male showing that frank neglect can be present in children with sustained attention problems without a clear aetiological event, or obvious structural brain abnormalities as indicated by a normal MRI. Experimental amelioration of the neglect through left-hand movement and externally alerting stimulation by uninformative sounds further suggest close similarities to the adult disorder. We suggest that such distortions of spatial attention may be more common in childhood than previously thought.

Acoustic Stimulation↗

PubMed2003

A case of unilateral neglect in Huntington's disease.

Unilateral neglect, an attentional deficit in detecting and acting on information coming from one side of space, is a relatively common consequence of right hemisphere stroke. Although neglect has been observed following damage to a variety of brain structures, to date no reports exist of neglect phenomena arising from Huntington's Disease (HD). However, reports in the animal and human literature suggest that neglect is possible following damage to a primary site for Huntington's pathology, the basal ganglia. Here we present a patient (BG) with genetically proven HD who, in the context of the mild intellectual, executive and attentional impairments associated with the disorder, showed a remarkably severe and stable neglect for left space. MRI and electrophysiological results make it unlikely that the spatial bias could be accounted for by basic sensory loss. In addition, behavioural investigation indicated that, although BG's neglect operated in a very striking manner along body-centred co-ordinates (missing almost all information presented to her left), more general limitations in visual attention were apparent to the left-side of information presented entirely to the right of the body midline. Further evidence is presented showing that the neglect was manifest on tactile and auditory tasks as well as those presented in the visual domain. The presence of neglect in HD in this case is novel and somewhat puzzling, particularly as flourodeoyglucose positron emission tomography revealed bilateral caudate hypoperfusion. Reducing the statistical threshold on this analysis revealed a potential frontal hypometabolism that was more marked in the right than left hemisphere. However, as this was only apparent at a threshold below that normally considered acceptable (due to the resulting number of false positives), this possible account of the neglect must be viewed very cautiously.

Attention↗

PubMed2003

Enhancing the sensitivity of a sustained attention task to frontal damage: convergent clinical and functional imaging evidence.

Despite frequent reports of poor concentration following traumatic brain injury, studies have generally failed to find disproportionate time-on-task decrements using vigilance measures in this patient group. Using a rather different definition, neuropsychological and functional imaging research has however linked sustained attention performance to right prefrontal function--a region likely to be compromised by such injuries. These studies have emphasised more transitory lapses of attention during dull and ostensibly unchallenging activities. Here, an existing attention measure was modified to reduce its apparent difficulty or 'challenge'. Compared with the standard task, its capacity to discriminate traumatically head-injured participants from a control group was significantly enhanced. Unlike existing functional imaging studies, that have compared a sustained attention task with a no-task control, in study 2 we used positron emission tomography to contrast the two levels of the same task. Significantly increased blood flow in the dorsolateral region of the right prefrontal cortex was associated with the low challenge condition. While the results are discussed in terms of a frontal system involved in the voluntary maintenance of performance under conditions of low stimulation, alternative accounts in terms of strategy application are considered.

Adult↗

PubMed2002

Coffee in the cornflakes: time-of-day as a modulator of executive response control.

Previous self-report based research has revealed a heightened propensity to slips-of-action in the early morning and at the end of the day. Here, we examined performance variability among healthy young adults as a function of time-of-day on a clinical task that is sensitive to absent-minded slips in brain-injured groups. We found significantly higher error rates at 1 pm and 7 pm compared with 1 am and 7 pm, and significant correlations between errors and two subjective sleepiness scales. No circadian modulation of the more routine aspects of the task was observed suggesting some specificity to the effect. Given evidence that the circadian cycle differentially affects different brain regions, and links between sleep deprivation and 'normal' dysexecutive behaviour, examining variation over the course of the day can prove a useful additional methodology in this area

Adolescent↗

PubMed2002

Rehabilitation of executive function: facilitation of effective goal management on complex tasks using periodic auditory alerts.

The 'dysexecutive syndrome' represents a major challenge to functional recovery and adaptation following brain injury--and an important target for rehabilitation. Previous reports of everyday difficulties, and performance on complex, life-like tasks, indicate that an adequately represented goal may become neglected as patients become overly engaged in current activity. Here we examine whether the provision of brief auditory stimuli, acting to interrupt current activity and to cue patients to consider their overall goal, would improve performance in a complex task. Ten brain injured patients completed a modification of Shallice and Burgess' Six Elements task under two conditions. In the 'Hotel' test, the patients were asked to try and do some of each of five sub-tasks within 15 min. As the total time to complete all of the tasks would exceed an hour, the measure emphasises patients' ability to monitor the time, switch between the tasks and keep track of their intentions. Without the external auditory cues, the patients performed significantly more poorly than age- and IQ-matched control volunteers, a common error being to continue performing one task to the detriment of beginning or allocating sufficient time to others. When exposed to the interrupting tones, however, their performance was both significantly improved and no longer significantly different from the control group on important variables. The results have value in assessment in helping to attribute poor performance to 'goal neglect' rather than, for example, poor memory or comprehension. They also suggest that providing environmental support to one aspect of executive function may facilitate monitoring and behavioural flexibility--and therefore the useful expression of other skills that may be relatively intact.

Acoustic Stimulation↗

PubMed2002

Is motor perseveration in unilateral neglect 'driven' by the presence of neglected left-sided stimuli?

Unilateral spatial neglect refers to a difficulty in detecting or acting on information in a particular region of space. When asked to cross out stimuli distributed across a page, patients with neglect may miss many targets on the left. In addition, they have a tendency to return to, and re-mark, right-sided targets that they have already cancelled. A recent retrospective study has shown this effect to be specific to unilateral neglect rather than a consequence of right hemisphere damage in general. Here, a consecutive group of seven right-hemisphere neglect patients performed five versions of a standard cancellation task, each version differing in the quantity of left-sided information presented. All of the participants showed perseveration on right-sided targets in the basic task. A highly significant and linear reduction in perseverative behaviour was observed as left-sided information was removed. In a second study, left-sided targets were again progressively removed but, in this case, were replaced with an additional distractor item, keeping the total quantity of stimuli presented in each condition constant. Again, a significant reduction in right-sided perseveration was observed, indicating a high degree of selectivity to the effect. The results show that a difficulty in perceiving existing cancellation marks, or a non-spatially specific motoric perseveration, are unlikely to fully account for this behaviour. As the patients omitted almost all targets on the left side of the basic cancellation task, the results suggest a striking influence on apparently intentional behaviour from un-cancelled information within the neglected field.

Aged↗

PubMed2002

The application of "dysexecutive syndrome" measures across cultures: performance and checklist assessment in neurologically healthy and traumatically brain-injured Hong Kong Chinese volunteers.

Deficits in planning, self-regulation and attention are a relatively common consequence of traumatic brain injury (TBI). Such "dysexecutive" deficits tend to be most exposed in complex, real world situations. Consequently, clinicians often have to rely on interviews, questionnaires and observation in their assessments. While there is little doubt that dysexecutive symptoms occur across different cultures, the expression of those symptoms, the way in which they are experienced by others, and the propensity of friends/relatives to report negative features may vary considerably. The cross-cultural use of standardized checklists and measures that have predominantly been studied with English speaking, Western groups therefore requires empirical support. Here a group of 68 healthy Chinese speaking volunteers were asked to complete translations of 2 UK developed questionnaires (the Dysexecutive Questionnaire and Cognitive Failures Questionnaire) measures and to perform 2 "executive" tasks (The Six Elements Test and the Tower of Hanoi). Their self ratings and the ratings of close relatives were very close to those seen in the original UK standardization samples--as was their performance on the 2 tasks. Accordingly, the conditions for assessing their clinical sensitivity were met. Comparison between 30 Chinese patients with TBI and matched controls showed that both questionnaires and tests were sensitive to the deficits in this group.

Adult↗

PubMed2002

Detecting residual cognitive function in persistent vegetative state.

Despite converging agreement about the definition of persistent vegetative state, recent reports have raised concerns about the accuracy of diagnosis in some patients, and the extent to which, in a selection of cases, residual cognitive functions may remain undetected. Objective assessment of residual cognitive function can be extremely difficult as motor responses may be minimal, inconsistent, and difficult to document in many patients, or may be undetectable in others because no cognitive output is possible. Here we describe strategies for using H(2)(15)O positron emission tomography activation studies to study covert cognitive processing in patients with a clinical diagnosis of persistent vegetative state. Three cases are described in detail. Of these, two exhibited clear and predicted regional cerebral blood flow responses during well-documented activation paradigms (face recognition and speech perception) which have been shown to produce specific, robust and reproducible activation patterns in normal volunteers. Some months after scanning, both patients made a significant recovery. In a third case, blood flow data were acquired during a speech perception task, although methodological difficulties precluded any systematic interpretation of the results. In spite of the multiple logistic and procedural problems involved, these results have major clinical and scientific implications and provide a strong basis for the systematic study of possible residual cognitive function in patients diagnosed as being in a persistent vegetative state.

Adult↗

PubMed2000

The effect of contralesional limb activation training and sustained attention training for self-care programmes in unilateral spatial neglect.

PURPOSE: To evaluate the effectiveness of two rehabilitation techniques for unilateral spatial neglect, contra-lesional limb activation and sustained attention training, on impaired activities of daily living. METHODS: Two single case, time-series designs incorporating baseline, intervention and post-intervention phases. RESULTS: Significant improvements were observed in both neuropsychological measures and in the independent performance of everyday activities coincident with the start of training. The benefits were well maintained during the post-training period. CONCLUSIONS: The results support the use of the two techniques in achieving functional goals for unilateral neglect patients.

Journal Article↗