Biomedical subjects

Helen Wright

Publications and source records attributed to Helen Wright.

5 recordsLinked to original sources

PubMed2006

Prosopagnosia following nonconvulsive status epilepticus associated with a left fusiform gyrus malformation.

A 67-year-old, right-handed woman became unable to recognize familiar faces following a period of nonconvulsive status epilepticus. Neuropsychological assessment revealed a relatively selective impairment of familiar face recognition in the absence of low-level visual deficits or widespread cognitive impairment. MRI scanning demonstrated an isolated lesion, probably a venous angioma, involving the left fusiform gyrus, mirror-symmetrical to the site typically linked to prosopagnosia. Potential explanations for the patient's prosopagnosia include seizure-related damage to a left fusiform region required for fully competent face recognition and damage to the contralateral fusiform gyrus via interhemispheric connections. Focal neuropsychological deficits in patients with refractory partial epilepsy who develop nonconvulsive status epilepticus may be underdiagnosed.

Aged↗

PubMed2005

Do chronic primary insomniacs have impaired heat loss when attempting sleep?

For good sleepers, distal skin temperatures (e.g., hands and feet) have been shown to increase when sleep is attempted. This process is said to reflect the body's action to lose heat from the core via the periphery. However, little is known regarding whether the same process occurs for insomniacs. It would be expected that insomniacs would have restricted heat loss due to anxiety when attempting sleep. The present study compared the finger skin temperature changes when sleep was attempted for 11 chronic primary insomniacs [mean age = 40.0 years (SD 13.3)] and 8 good sleepers [mean age = 38.6 years (SD 13.2)] in a 26-h constant routine protocol with the inclusion of multiple-sleep latency tests. Contrary to predictions, insomniacs demonstrated increases in finger skin temperature when attempting sleep that were significantly greater than those in good sleepers (P = 0.001), even though there was no significant differences in baseline finger temperature (P = 0.25). These significant increases occurred despite insomniacs reporting significantly greater sleep anticipatory anxiety (P < 0.0008). Interestingly, the core body temperature mesor of insomniacs (37.0 +/- 0.2 degrees C) was significantly higher than good sleepers (36.8 +/- 0.2 degrees C; P = 0.03). Whether insomniacs could have impaired heat loss that is masked by elevated heat production is discussed.

Adult↗

PubMed2005

The treatment of early-morning awakening insomnia with 2 evenings of bright light.

STUDY OBJECTIVE: To assess the effectiveness of brief bright-light therapy for the treatment of early-morning awakening insomnia. PARTICIPANTS: Twenty-four healthy adults with early-morning awakening insomnia were assigned to either the bright-light condition (2,500-lux white light) or the control (dim red light) condition. MEASUREMENTS AND RESULTS: The circadian phase of rectal temperature and urinary melatonin rhythms were assessed with 26-hour constant routines before and after 2 evenings of light therapy. Sleep and daytime functioning were monitored using sleep diaries, activity monitors, and mood scales before light therapy and for 4 weeks during the follow-up period. While there were no significant circadian phase changes in the dim-light control group, the bright-light group had significant 2-hour phase delays of circadian temperature and melatonin rhythm. Compared to pretreatment measures, over the 4-week follow-up period, the bright-light group had a greater reduction of time awake after sleep onset, showed a trend toward waking later, and had a greater increase of total sleep time. Participants in the bright-light condition also tended to report greater reductions of negative daytime symptoms, including significantly fewer days of feeling depressed at the 4-week follow-up, as compared with the control group. CONCLUSION: Two evenings of bright-light exposure phase delayed the circadian rhythms of early-morning awakening insomniacs. It also improved diary and actigraphy sleep measures and improved some indexes of daytime functioning for up to 1 month after light exposure. The study suggests that a brief course of evening bright-light therapy can be an effective treatment for early-morning awakening insomniacs who have relatively phase advanced circadian rhythms.

Adult↗

PubMed2004

Individual differences in deductive reasoning.

Three studies are reported, which examined individual differences in deductive reasoning as a function of intellectual ability and thinking style. Intellectual ability was a good predictor of logical performance on syllogisms, especially where there was a conflict between logic and believability. However, in the first two experiments there was no link between ability and performance on indicative selection tasks, in sharp contrast to previous research. This correlation did, however, return in the final study. Our data are consistent with the claim that the correlation with logical accuracy on abstract selection tasks is found primarily with participants of relatively high ability. At lower levels, pragmatically cued responses are given but those of slightly higher ability divorce the rule from the scenario and respond consistently (though incorrectly) across problems. Self-report questionnaires were generally poor predictors of performance, but a measure of the ability to generate alternative representations proved an excellent predictor. These results are consistent with a mental models approach to reasoning and also have implications for the debate about human rationality.

Adult↗

PubMed2002

Melatonin and circadian rhythms.

Melatonin synthesis and secretion by the pineal gland is under the control of the suprachiasmatic nucleus and consequently has a profound circadian rhythm. In this review we discuss some of the issues surrounding the measurement of melatonin rhythmicity in biological fluids and the factors that influence melatonin circadian rhythmicity, including light and drugs. We also review the role of melatonin rhythmicity in sleep timing and sleep initiation.

Animals↗