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Biomedical subjects

J Currie

Publications and source records attributed to J Currie.

At least 55 records · Page 3Linked to original sources
PubMed1995

Presentation of acute Wernicke's encephalopathy and treatment with thiamine.

Thirty two cases of acute Wernicke's encephalopathy were observed in a period of 33 months, and prior to the mandatory thiamine enrichment of Australian bread-making flour in 1991. These cases were carefully assessed by multiple tests at specified intervals prior to, and following thiamine administration until discharge from hospital. Structured scoring of neurological signs and symptoms, CT scans, psychometry, nutritional measurements, and liver biopsies were performed. There was variation in the presentation and severity of clinical signs and symptoms and in response to treatment. All patients had alcohol-related liver disease, and the results indicated that fatty liver was important in presentation and in response to treatment with thiamine. Other forms of alcohol related brain damage were present in these patients, most of whom were in the 4th or 5th decade of life and had been drinking beer to excess for more than 20 years.

Alcoholic Intoxication↗
PubMed1995

An attentional grasp reflex in patients with Alzheimer's disease.

Motor and visual grasp reflexes often occur as part of the symptomatology of Alzheimer's disease (AD). Similar grasp reflexes may also be associated with the impaired performance of AD patients on tasks which require direction of visual attention without eye movements. The covert orienting of visual attention task (COVAT) requires subjects to keep their eyes fixed on a central point and manually respond to the appearance of a peripheral target in one of two locations in the left or right visual field. Before the target appears, a cue is presented at either the target location or the contralateral location to the target, although the nature of the cue is not known until the target appears. We hypothesised that the attentional grasp reflex would become evident in patients with AD when attentional shifts away from the cue were required but there was no target for the shift present. Twelve patients who met the clinical criteria for AD and 12 age and education matched controls were administered three COVAT conditions in which the target appeared at the cued location with either an 80, 50 or 20% probability. For the 80 and 50% probability conditions. RTs for targets at the cued location were significantly faster than RTs for targets contralateral to the cue in both AD subjects and controls indicating that AD subjects were able to disengage attention when there was a target for the attentional shift. For the 20% probability condition, control subjects showed significantly faster RTs for targets appearing contralateral to the cue than for targets at the cued location indicating that when they expected the target to appear in the opposite visual field to the cue, they could initiate the shift of attention before the target appeared. However, AD subjects continued to show significantly faster RTs for targets at the cued location than for targets appearing contralateral to the cue, despite the high probability that targets would not occur at the cued location. This suggests that the covert redirection of attention away from a peripheral visual cue could not be initiated until the contralateral target appeared. Taken together these results suggest an attentional grap reflex in patients with AD.

Aged↗
PubMed1995

Asymmetries in the covert orienting of visual spatial attention in schizophrenia.

The presence of attentional asymmetries in patients with schizophrenia was investigated with particular emphasis on the effects of stage of disease, medication status and clinical symptom severity. A modified version of Posner's covert orienting of visual attention task (COVAT) which included both spatial and non-spatial cues was administered to six volunteer samples of subjects which consisted of (i) 15 unmedicated and acutely psychotic male subjects with schizophrenia, (ii) 15 male subjects with schizophrenia who had been receiving medication for 14-21 days, (iii) 10 chronic male schizophrenic subjects who had been receiving medication for at least two years, (iv) 10 acutely psychotic male subjects with non-schizophrenic psychoses, (v) 15 subjects with unilateral brain frontal lobe (n = 6) or parietal lobe (n = 9) lesions, (vi) and 15 male control subjects. Measures of saccadic and pursuit eye movements were also obtained from unmedicated and recently medicated subjects with schizophrenia. COVAT attentional asymmetries were present in unmedicated subjects with schizophrenia for the 150 msec stimulus onset asynchrony (SOA). These asymmetries arose because reaction times (RTs) to right visual field targets were significantly slower than RTs to left visual field targets when targets followed invalid spatial or non-spatial cues. These asymmetries were qualitatively similar to those found in the patients with unilateral parietal lobe lesions. Attentional asymmetries partially resolved with brief periods of medication and completely resolved with long periods of medication. No asymmetries were found in controls nor in unmedicated subjects without schizophrenia. No asymmetries of ocular motor function were found. In schizophrenia, attentional asymmetries may reflect a deficit in the disengagement of visual attention from the right visual field and appear to be a stage marker for the disease. However this attentional deficit is dynamic and may reflect disruption to the neurocognitive network controlling attention at the level of the anterior cingulate cortex.

Adolescent↗
PubMed1995

Asymmetries in the covert orienting of visual spatial attention to spatial and non-spatial cues in Alzheimer's disease.

The ability to direct covert visual spatial attention to the left (LVF) and right visual field (RVF) was examined in 15 patients with mild to moderate Alzheimer's disease and 15 age- and education-matched controls using the covert orienting of visual spatial attention task (COVAT) modified to include both spatial and non-spatial cues. Subjects responded with a button press when they detected a target at a location 8 degrees to either the left or right of fixation. On 70% of trials a spatial cue was flashed at the target location before the target appeared. On 15% of trials the spatial cue was flashed at the location contralateral to where it would appear and on the remaining 15% of trials non-spatial diffuse cue preceded targets. The cue to target interval (CTI) varied between 150 and 550 ms. Mean reaction times for each cuetype in the RVF and LVF were calculated. Compared with controls, the percentage of trials excluded because of very slow reaction times was significantly greater in the Alzheimer's disease group for the 550 ms CTI. Analysis of the symmetry of reaction times to LVF and RVF targets for the 150 ms CTI enabled us to classify Alzheimer's disease subjects into three subgroups based on the hemifield of abnormally slow attentional biases. The first subgroup showed a significant slowing of reaction time to all LVF targets, the second showed a significant slowing of reaction time to all RVF targets and the third showed a significant slowing of reaction time to both LVF and RVF targets. Patients with Alzheimer's disease who showed an abnormal attentional bias performed significantly better on neuropsychological tests of memory, language and executive function than Alzheimer's disease patients with no attentional bias. Eight of the Alzheimer's disease subjects were assessed serially on at least six occasions over a 12-month period. The initial classification of abnormal attentional bias or no attentional bias was reliable for seven Alzheimer's disease subjects. One Alzheimer's disease subject, initially classified as having a slowed rightward attentional bias, in subsequent testing over the 12-month period was more consistent with symmetrical COVAT performance. Control subjects showed no attentional biases over the 12-month period and the magnitude of asymmetric attentional slowing over the 12-month period was significantly more variable in individual Alzheimer's disease subjects than in controls. The presence of subgroups of patients with Alzheimer's disease with qualitatively different COVAT performance indicates a large between-subject variability in attentional deficits in Alzheimer's disease. The presence of asymmetric attentional slowing and milder neuropsychological deficits in a subgroup of patients with Alzheimer's disease suggests that in these patients there is functional impairment of attentional areas in only one hemisphere rather than an asymmetric impairment of both hemispheres and that the neurodegenerative disease process may have been less advanced or in an earlier stage than that present in Alzheimer's disease patients with symmetric attentional performance and bilateral COVAT impairment. The preservation of asymmetric attentional slowing over time, together with the increased intra-subject variability in the magnitude of these asymmetries, suggests that asymmetrical COVAT performance represents a reliable reflection of underlying hemispheric function in Alzheimer's disease, although designation of asymmetrical attentional biases should be made on the basis of two or more sequential testing sessions.

Aged↗
PubMed1995

Anaesthesia for a child with centronuclear myopathy.

Centronuclear myopathy (CNM) is an inherited condition involving most muscle fibres in all the body mass, first described in 1966, which has a varying spectrum of presentations. Until recently it had not been associated with an increased risk of malignant hyperpyrexia. A seven-year-old male with CNM was admitted to our hospital for elective surgery. High dose propofol anaesthesia was used, supplemented with N2O/O2 from a new anaesthesia machine. The operation was successful with uncomplicated anaesthesia and recovery.

Anesthesia, General↗
PubMed1995

Abnormalities of visual spatial attention in HIV infection and the HIV-associated dementia complex.

Covert orienting of visuospatial attention (COVAT) was examined in 88 homosexual or bisexual men: 12 with mild HIV-associated dementia complex (ADC), 30 neurologically intact with AIDS (NI-AIDS), 23 asymptomatic HIV+ (HIV+ASX), and 23 HIV-negative control subjects. In mild ADC, COVAT was normal for spatial but impaired for nonspatial cues; 17% of NI-AIDS and HIV+ASX subjects had similar COVAT impairment patterns and also showed cognitive deficits. HIV+ subjects with normal COVAT showed normal cognitive performance. Impairment of nonspatial attentional processing in the ADC subjects and subgroups of the neurologically intact HIV+ subjects may reflect early subcortical dysfunction caused by HIV infection. COVAT assessment may be sensitive for detection of early subclinical neurological impairment in HIV infection.

AIDS Dementia Complex↗
PubMed1994

Neuropsychological characterization of the AIDS dementia complex and rationalization of a test battery.

OBJECTIVE: To define the neuropsychological deficits present in mild human immunodeficiency virus type 1 (HIV-1) associated with the acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) and to develop a rational neuropsychological test battery for its diagnosis. DESIGN: Survey. SETTING: Subjects were recruited from large metropolitan hospital outpatient clinics and were all living independently in the general community. PATIENTS: Three volunteer samples of homosexual-bisexual men: (1) 15 patients who met clinical and research criteria for mild ADC; (2) 27 HIV-seronegative (HIV-) controls; and (3) 17 patients with AIDS who were neurologically intact (NI-AIDS) who were matched with the ADC subjects by CD4 lymphocyte counts for severity of systemic HIV disease. MAIN OUTCOME MEASURES: Neuropsychological test performance; z score comparisons were made with the HIV-control group using 2.25-SD cutoffs for abnormality. RESULTS: Compared with NI-AIDS subjects, performance of patients with mild ADC was markedly worse in the cognitive areas of executive function, memory, and complex attention but not in affect or the cognitive areas of simple motor function, orientation, language, or visuospatial construction. Within the areas of executive function, memory, and complex attention, all of the HIV-controls and 95% of the NI-AIDS subjects had impaired test performance in a maximum of one area only. In marked contrast, 14 (93%) of the 15 patients with mild ADC had abnormal test performances in all three of these cognitive areas. Using a criterion of abnormal performance in at least two of the cognitive areas of executive function, memory, and complex attention, all patients with mild ADC could be differentiated from HIV-controls with 100% sensitivity and specificity and from NI-AIDS subjects matched for disease severity by CD4 lymphocyte count with 100% sensitivity and 94% specificity, which increased to 100% with the requirement of impairment in all three cognitive areas. CONCLUSIONS: If time constraints or patient compliance limit neuropsychometric testing, examination to detect mild ADC first should be directed to the areas of executive function, memory, and complex attention. This pattern of neuropsychological deficits in patients with mild ADC is suggestive of subcortical dementia.

AIDS Dementia Complex↗
PubMed1994

Amoebiasis: a rare cause of cardiac tamponade.

Cardiac tamponade secondary to perforation of a hepatic amoebic abscess developed six years after the patient had visited an area where Entamoeba histolytica is endemic. He was treated with metronidazole and imipenem, emergency percutaneous catheter drainage, and open surgical drainage.

Adult↗
PubMed1994

Hirschsprung's disease associated with a deletion of chromosome 10 (q11.2q21.2): a further link with the neurocristopathies?

We report a patient with total colonic aganglionosis in association with a deletion of part of the long arm of chromosome 10: (del(10)(q11.2q21.2)). This deletion includes the ret proto-oncogene, which has recently been implicated in multiple endocrine neoplasia type 2A (MEN 2A). The possible links between Hirschsprung's disease and the neurocristopathies and the aetiological role of abnormalities of neural crest development in these conditions are discussed.

Cephalometry↗
PubMed1994

Computer-administered visual analogue mood scales: rapid and valid assessment of mood in HIV positive individuals.

Studies of cognition in patients with the human immunodeficiency virus must take into account the effects of mood. Standardised mood-rating questionnaires are oftentimes consuming and fatiguing for such patients and so may be omitted from experiments. Visual analogue rating scales for affective state are rapidly administered and are quite acceptable to subjects. In 64 HIV seropositive homosexual or bisexual males, measures of anxiety and depression derived from two computer-administered visual analogue scales were compared with anxiety and depression ratings from the Spielberger State-Trait Anxiety Inventory and the Center for Epidemiological Studies-Depression. Analogue ratings of anxiety correlated .80 with STAI State anxiety and .58 with STAI Trait anxiety measures and analogue ratings of depression correlated .78 with CES-Depression measures. Analogue ratings may differentiate situational anxiety and depression more effectively and so are valid tools in assessment of anxiety and depression in HIV seropositive subjects. These may be of particular value when limitations of time or patient illness require a rapid assessment of mood variables in neuropsychiatric research.

AIDS Dementia Complex↗
PubMed1994

Central ocular motor disorders.

Our understanding of the complexities of the central mechanisms that control human eye movements continues to expand rapidly under the twin impetus of more widespread use of high-resolution eye movement recording techniques and improved anatomical localization of lesions using magnetic resonance imaging. In parallel, there has been continued expansion of sophisticated neurophysiological studies in monkeys examining basic ocular motor control mechanisms. Another important area that is now rapidly expanding is the application to human diseases of more complex and cognitively demanding saccadic eye movement stimulus paradigms such as antisaccades, memory-guided saccades, and express saccades. Finally, a much clearer understanding and exposition of the complexities of central vestibular function appears to be gathering pace.

Animals↗
PubMed1994

Fibre type composition of rabbit tibialis anterior and extensor digitorum longus muscles.

Rabbit tibialis anterior (TA) and extensor digitorum longus (EDL) muscles are used extensively in studies of stimulation-induced fibre type transformation, but the proportions and sizes of the 2 main fibre types, and the way in which they are distributed within the muscles, have never been described in any detail. In this study, transverse sections were processed by enzyme histochemical and immunohistochemical techniques and assessed morphometrically. The data were analysed by multivariate methods. In both TA and EDL muscles, the proportion of type 1 fibres varied significantly, and to a similar extent, within a cross-section, from lateral to medial and from superficial to deep parts. The fibre density, an indirect estimate of the mean muscle fibre area, also varied significantly, but not systematically, within a cross-section. For the EDL muscle, the proportion of type 1 fibres was consistently higher in the distal than in the proximal part of the muscle. The proportion of type 1 fibres was also significantly higher in the EDL than in the TA muscle for each of the 6 rabbits. There was no systematic variation between muscles from left and right limbs. The type proportions and fibre densities for both TA and EDL muscles differed significantly between individual rabbits, but not between sexes. The study provides a database that has hitherto been lacking on normal fibre type composition and its variation within and between these experimentally important muscles.

Adenosine Triphosphatases↗
PubMed1993

Selective impairment of express saccade generation in patients with schizophrenia.

When a temporal gap is introduced between the offset of a central fixation point and the onset of a peripheral saccadic target, normal subjects generate an increased number of short latency (90-150 ms) saccades, termed express saccades, and the profile of express saccade frequency across different gap sizes for any individual subject, even if untrained in the task, shows a high test-retest reliability. In patients with schizophrenia, the generation of express saccades was also normal for gap sizes of 200-300 ms or in an overlap task (gap = 0 ms). However, for temporal gaps of 50-150 ms, the generation of express saccades was significantly impaired in the schizophrenic subjects. This selective deficit appeared to be independent of the patients' neuroleptic medication status and did not correlate with the severity of schizophrenic symptoms. It is postulated that the successful execution of an express saccade requires that the cognitive operations of disengagement of visual attention and selection of the appropriate motor command to generate a saccade both be commenced or completed during the temporal gap between fixation offset and peripheral target onset. Our results suggest that, in schizophrenia, there is an impairment in the cortical/subcortical neural network that generates express saccades and controls these cognitive operations. Potential sites for such dysfunction in schizophrenia include the parietal cortex and the GABA-ergic function of the superior colliculus.

Adult↗