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Biomedical subjects

Keith Wesnes

Publications and source records attributed to Keith Wesnes.

13 recordsLinked to original sources
PubMed2003

Aromas of rosemary and lavender essential oils differentially affect cognition and mood in healthy adults.

This study was designed to assess the olfactory impact of the essential oils of lavender (Lavandula angustifolia) and rosemary (Rosmarlnus officinalis) on cognitive performance and mood in healthy volunteers. One hundred and forty-four participants were randomly assigned to one of three independent groups, and subsequently performed the Cognitive Drug Research (CDR) computerized cognitive assessment battery in a cubicle containing either one of the two odors or no odor (control). Visual analogue mood questionnaires were completed prior to exposure to the odor, and subsequently after completion of the test battery. The participants were deceived as to the genuine aim of the study until the completion of testing to prevent expectancy effects from possibly influencing the data. The outcome variables from the nine tasks that constitute the CDR core battery feed into six factors that represent different aspects of cognitive functioning. Analysis of performance revealed that lavender produced a significant decrement in performance of working memory, and impaired reaction times for both memory and attention based tasks compared to controls. In contrast, rosemary produced a significant enhancement of performance for overall quality of memory and secondary memory factors, but also produced an impairment of speed of memory compared to controls. With regard to mood, comparisons of the change in ratings from baseline to post-test revealed that following the completion of the cognitive assessment battery, both the control and lavender groups were significantly less alert than the rosemary condition; however, the control group was significantly less content than both rosemary and lavender conditions. These findings indicate that the olfactory properties of these essential oils can produce objective effects on cognitive performance, as well as subjective effects on mood.

Adult↗
PubMed2003

Regulation of attention and response to therapy in dementia by butyrylcholinesterase.

OBJECTIVES: To determine the response of patients with different butyrylcholinesterase genotypes to therapy, and the influence of butyrylcholinesterase on cognition. Acetylcholine plays a key role in attention and memory and reduced cortical acetylcholine is associated with the severity of dementia. Inhibitors of the enzyme acetylcholinesterase are an effective dementia treatment, though the role of the related enzyme butyrylcholinesterase is less well understood. METHODS: We examined the response of a cohort of dementia patients enrolled in a trial of a cholinesterase inhibitor who had been genotyped at the butyrylcholinesterase locus. Additionally a prospectively assessed cohort of dementia patients was genotyped and rate of cognitive decline examined, along with baseline cognitive performance in a group of elderly non-demented individuals. We identified that the presence of reduced-activity butyrylcholinesterase variants correlates with preserved attentional performance and reduced rate of cognitive decline. During cholinesterase inhibitor therapy, patients with normal butyrylcholinesterase show improved attention, though patients carrying reduced-activity enzyme do not, possibly due to being at ceiling performance. Butyrylcholinesterase did not however affect attentional performance in non-demented individuals with mild cognitive impairment. CONCLUSIONS: These findings indicate that the butyrylcholinesterase enzyme is a major regulator of attention especially in cholinergic deficiency states through its ability to hydrolyse acetylcholine. Pharmacologic manipulation of this enzyme may be a viable strategy in dementia treatment and, with butyrylcholinesterase genotyping, may provide pharmacogenomic treatment of dementia.

Acetylcholine↗
PubMed2002

Apolipoprotein E epsilon 4 and short-term recovery from predominantly mild brain injury.

OBJECTIVE: To determine whether APOE genotype explained variability in short-term recovery from predominantly mild traumatic brain injury (TBI). METHODS: A total of 87 adult patients presenting with mild or moderate TBI to a shock trauma center were enrolled prospectively. A battery of 13 neuropsychological tests was administered twice, at approximately 3 and 6 weeks after injury. Eighty of 87 patients were successfully genotyped for APOE using a buccal swab technique. RESULTS: Ninety percent of study patients had mild TBI (Glasgow Coma Scale score of 13 to 15); 18 (22.5%) had one APOE epsilon 4 and none had two epsilon 4 alleles. After adjusting for potential confounders, patients positive for the APOE epsilon 4 allele had lower mean scores on 12 of 13 neuropsychological outcomes at visit 1 compared with APOE epsilon 4-negative patients. Two of the differences were significant (grooved pegboard test, p = 0.005; paced auditory serial addition task 2.8-second trial, p = 0.004). At visit 2, APOE epsilon 4-positive patients had lower adjusted mean scores on 11 of the 13 neuropsychological outcomes. None of the differences was significant. CONCLUSIONS: APOE genotype may influence the severity of the acute injury. However, with no consistent pattern to the recovery curves, it is not clear if APOE genotype influences the rate of recovery.

Adolescent↗
PubMed2002

Assessing cognitive function in clinical trials: latest developments and future directions.

Properly developed automated test systems are of value for assessing changes in cognitive function in clinical trials. Besides the other advantages that automation brings to trials, such as increased reliability and utility, it is shown that such systems are also more sensitive to change in cognitive function than traditional nonautomated procedures. Data from a variety of topical areas in drug development are presented to illustrate the added value such techniques have brought. The latest developments in automation include remote testing via the Internet and telephone.

Attention↗
PubMed2002

The acute nootropic effects of Ginkgo biloba in healthy older human subjects: a preliminary investigation.

Ginkgo biloba has been shown to have chronic memory enhancing effects in healthy subjects and patients with dementia. There is limited research on the acute nootropic effects of Ginkgo biloba in humans. The current study aimed to examine the acute effects of Ginkgo biloba (120 mg) on memory functioning in healthy older volunteers using the cognitive drug research (CDR) battery of memory tests and the Rey auditory verbal learning task (AVLT). The study was a double-blind placebo-controlled design, with each participant tested under both placebo and Ginkgo biloba treatment conditions. Testing was conducted pre- and 90 min post-drug administration for each treatment condition. Treatment conditions were separated by a 7 day wash out period. No acute effects of Ginkgo biloba were found for any of the memory tests examined. The findings suggest that 120 mg of Ginkgo biloba has no acute nootropic effects in healthy older humans.

Aged↗
PubMed2002

A pharmacokinetic and pharmacodynamic drug interaction study of acamprosate and naltrexone.

Acamprosate and naltrexone have each demonstrated safety and efficacy for alcohol dependence in placebo-controlled clinical trials. There is scientific and clinical interest in evaluating these drugs in combination, given their high tolerability, moderate effect sizes, different pharmacological profiles and potentially different effects on drinking outcomes. Thus, this is the first human pharmacokinetic and pharmacodynamic drug interaction study of acamprosate and naltrexone. Twenty-four normal, healthy adult volunteers participated in a double-blind, multiple dose, within subjects, randomized, 3-way crossover drug interaction study of the standard therapeutic dose of acamprosate (2 g/d) and the standard therapeutic dose of naltrexone (50 mg/d), given alone and in combination, with seven days per treatment condition and seven days washout between treatments. Blood samples were collected on a standardized schedule for pharmacokinetic analysis of naltrexone, 6-beta-naltrexol, and acamprosate. A computerized assessment system evaluated potential drug effects on cognitive functioning. Coadministration of acamprosate with naltrexone significantly increased the rate and extent of absorption of acamprosate, as indicated by an average 33% increase in acamprosate maximum plasma concentration, 33% reduction in time to maximum plasma concentration, and 25% increase in area under the plasma concentration-time curve. Acamprosate did not affect the pharmacokinetic parameters of naltrexone or 6-beta-naltrexol. A complete absence of negative interactions on measures of safety and cognitive function supports the absence of a contraindication to co-administration of acamprosate and naltrexone in clinical practice.

Acamprosate↗
PubMed2002

Neuropsychological deficits in older stroke patients.

This paper examines the frequency of CIND, the profile of early cognitive deficits in stroke patients, the differences in the profile of cognitive impairment in people with CIND and those with vascular dementia, and the MRI associations of CIND in older stroke patients.

Aged↗
PubMed2002

Cognitive associations of subcortical white matter lesions in older people.

Hyperintense lesions (HL), as visualized on T2-weighted or FLAIR MRI, are a common finding in older people, but their clinical significance and influence on cognitive function remain to be clarified. We investigated the relationship between HL in deep white and gray matter structures and cognition in older subjects. We recruited 154 nondemented (Mini-Mental State Examination > 24) subjects (79 males) over the age of 70 from primary care (103 subjects with mild hypertension and 51 normotensive subjects). All subjects underwent FLAIR and proton density and T2-weighted axial 1.5-tesla MRI scans (slice thickness: 5 mm). The scans were rated for the presence and distribution of HL in the subcortical gray matter (caudate, putamen, globus pallidus, thalamus) and associated white matter tracts (internal/external capsule). Subjects (n = 149) underwent a comprehensive cognitive assessment involving tests of attention, processing speed, episodic memory, working memory, and executive function. Partial correlations (correcting for age, systolic blood pressure, and New Adult Reading Test [NART] score) were performed to investigate the relationship between cognition and white matter change. HL were found in 49% of subjects. HL in both the gray (thalamus and caudate) and white matter were significantly associated with impaired cognitive function in tasks involving processing speed and/or executive function, but showed no associations with episodic or working memory. HL in both subcortical gray matter structures and associated fiber tracts correlate with impairments in attention, executive function and processing, and memory retrieval speed in nondemented older community-dwelling subjects. Such lesions may be an important cause of age-related attentional and executive dysfunction in the elderly, as well as temporal lobe and hippocampal changes that have previously been reported to be associated with impairments to the ability to actually store and retrieve information from memory.

Aged↗
PubMed2002

The effect of glucose administration and the emotional content of words on heart rate and memory.

The effects of glucose administration and emotionality of target material on heart rate and memory were examined in a double-blind, placebo-controlled, balanced crossover study. Memory for neutral and emotional words was tested in 20 young adults following a glucose drink and a placebo. Heart rate and blood glucose were also measured. Emotional words were recalled and recognized better than neutral words in both drink conditions but there was no direct effect of drink type on memory. During the neutral word memory tasks, similar heart rate deceleration was observed in both drink conditions. However, during the processing of emotional material, heart rates were lowered in the placebo condition and relatively increased in the glucose condition. These results further differentiate the physiological responses involved during memory for affective and neutral material.

Adult↗
PubMedDate not supplied

Reliable diagnoses of dementia by the naive credal classifier inferred from incomplete cognitive data.

Dementia is a serious personal, medical and social problem. Recent research indicates early and accurate diagnoses as the key to effectively cope with it. No definitive cure is available but in some cases when the impairment is still mild the disease can be contained. This paper describes a diagnostic tool that jointly uses the naive credal classifier and the most widely used computerized system of cognitive tests in dementia research, the Cognitive Drug Research system. The naive credal classifier extends the discrete naive Bayes classifier to imprecise probabilities. The naive credal classifier models both prior ignorance and ignorance about the likelihood by sets of probability distributions. This is a new way to deal with small and incomplete datasets that departs significantly from most established classification methods. In the empirical study presented here, the naive credal classifier provides reliability and unmatched predictive performance. It delivers up to 95% correct predictions while being very robust with respect to the partial ignorance due to the largely incomplete data. The diagnostic tool also proves to be very effective in discriminating between Alzheimer's disease and dementia with Lewy bodies.

Alzheimer Disease↗