The circadian rest-activity cycle in Korsakoff psychosis.

OBJECTIVES: Alzheimer disease (AD) has been associated with diminished function of the biological clock in the suprachiasmatic nuclei (SCN) and pronounced circadian sleep-wake cycle disturbances. Few studies have investigated other dementia etiologies. Because alcohol acts on the SCN and modifies circadian rhythms in animal studies, Korsakoff psychosis (KP) may also be associated with circadian rhythm abnormalities. This pilot study investigated the rest-activity cycle of KP to see whether there were sleep-wake cycle disturbances similar to those that the authors had observed in patients with AD. DESIGN AND SETTING: Cross-sectional observational study in a single academic medical center. PARTICIPANTS, MEASUREMENTS: The authors investigated the circadian rest-activity cycle of six moderately demented patients with KP who wore an activity/lux monitor for 10-26 days and compared these patterns with those of six home-living healthy individuals of the same age group. In addition, rest-activity cycle data from previous studies of patients with AD were examined. INTERVENTIONS: None. RESULTS: The rest-activity cycle of KP was remarkably well entrained, without the marked circadian and sleep disturbances found in patients with AD on the same ward. KP had a >2 hour earlier bedtime and rest onset than healthy subjects and a 30-minute earlier wake-up time, resulting in longer nocturnal rest duration. The major difference was a greatly diminished daytime activity level and extremely low light exposure. CONCLUSION: A stably entrained, although low-amplitude and phase-advanced rest-activity cycle may reflect the different neuropathology of demented patients with KP compared with patients with AD.

Cold extremities and difficulties initiating sleep: evidence of co-morbidity from a random sample of a Swiss urban population.

Difficulties initiating sleep (DIS) can frequently occur in psychiatric disorders but also in the general population. The primary vasospastic syndrome is a functional disorder of vascular regulation in otherwise healthy subjects complaining of thermal discomfort from cold extremities (TDCE). Laboratory studies have shown a close relationship between long sleep onset latency and increased distal vasoconstriction in healthy young subjects. Considering these findings, the aims of the Basel Survey were to assess the prevalence rates for DIS and TDCE and to determine whether both symptoms can be associated in the general population. In a random population sample of Basel-Stadt, 2800 subjects (age: 20-40 years) were requested to complete a questionnaire on sleep behavior and TDCE (response rate: 72.3% in women, n = 1001; 60.0% in men, n = 809). Values of DIS and TDCE were based on questionnaire-derived scores. In addition, TDCE was externally validated in a separate group of subjects (n = 256) by finger skin temperature measurements--high TDCE values were significantly associated with low finger skin temperature. A total of 31.1% of women and 6.9% of men complain of TDCE. In contrast, prevalence rates of DIS were only slightly higher in women in comparison to men (9.3% versus 6.7%, P < 0.1). Irrespective of gender, each seventh subject complaining of TDCE had concomitant DIS and the relative risk in these subjects was approximately doubled. Therefore, a thermophysiological approach to DIS may be relevant for its differential diagnosis and its treatment.

Colour vision deficiencies in Alzheimer's disease.

OBJECTIVE: visual disorders are among the earliest symptoms of Alzheimer's disease. It is, however, still controversial as to whether Alzheimer's disease impairs colour vision. In this study, colour vision of Alzheimer's disease patients was tested using the Ishihara test and the PV-16 choice test. The latter test, primarily designed for children, was chosen in order to avoid problems due to cognitive decline. METHODS: 26 patients with mild to severe Alzheimer's disease (M:F=5:21; mean age: 80+/-9 years, range: 53-95 years) and 25 controls (M:F=5:20; mean age 80+/-10 years, range: 56-100 years) were rated after undergoing complete neuro-ophthalmologic examination. RESULTS: the Alzheimer's disease patients made significantly more unspecific errors in the Ishihara test (P=0.02) and in the PV-16 choice test (P=0.0008) than the controls. No relation between test performance and severity of Alzheimer's disease was found. CONCLUSIONS: Alzheimer's disease patients have an unspecific colour vision deficiency independent of the severity of the disease.

Decline in long-term circadian rest-activity cycle organization in a patient with dementia.

Continuous measurement of the circadian rest-activity cycle for 598 days in a demented patient with probable Alzheimer's disease revealed slow progressive changes in temporal organization until death. Circadian and sleep analysis of the actigraphic data provided objective documentation of the gradual insertion of wakefulness into rest and rest into wake periods. Pacing, a nonphotic zeitgeber strengthening, led to improved synchronization of the rest-activity cycle.