Hitoshi Fukuzawa

Age development and sex differences of various EEG elements in healthy children and adults — Quantification by a computerized wave form recognition method

The EEGs of 1416 healthy subjects aged 6-39 years were recorded and 1 min of background activity from Fp1, C3 and O1, was analyzed by a computerized wave form recognition method. Age development and sex differences of various EEG elements, which are employed in a conventional clinical EEG assessment, were statistically analyzed. The age developments of alpha and theta showed regional differences and were the most rapid in O1 and the slowest in C3. The delta amplitude, theta amplitude, theta continuity and percentage time of theta with an amplitude of 30 microV or more, which are important in a clinical EEG assessment, reached a stable level at 18-21 years of age in the 3 leads. The percentage time, amplitude and continuity of alpha in the 3 leads reached a stable level at 22-25 years of age. Including the low voltage theta in Fp1 and C3, all of the EEG elements reached the stable adult level at 26-29 years of age. Since there was a large interindividual variability in these age developments, the regression curves of the 10th and 90th percentiles of these EEG elements can be considered as quantitative standards for clinical EEG evaluation. As for sex differences, the percentage alpha time and alpha continuity were greater in males than in females after adolescence. The percentage theta time in Fp1 and C3 was greater in females than in males during childhood. The percentage beta time was higher in females than in males at all ages. But overall, these sex differences were minor compared with the differences associated with age developments of the EEG elements.

Validity of sleep log compared with actigraphic sleep-wake state II

Twenty‐five young people (Y group), three elderly people and seven people with various sleep disorders (SD group) kept a sleep log for 2–7 days, and their wrist‐activity was monitored simultaneously. The sensitivity and specificity of the sleep log, and the ratio of agreement between the sleep log and actigraphic sleep‐wake state were calculated. The sensitivity and specificity in Y group were 87.93 ± 6.49% and 96.51 ± 2.37%, respectively. The sensitivity in SD group was significantly lower than in Y group. Even in Y group one‐hour agreement ratios dropped during the sleep onset period.

Seasonal changes in human sleep–wake rhythm in Antarctica and Japan

Abstract The subjects were eight men of the Japanese Antarctic Research Expedition (average age 35.8 years), and 10 healthy people living around Kofu, Japan (28.9 years). They completed a sleep log for 12 to 18 months, and the sleep–wake state was scored in 10‐min epochs. Q24 values calculated by χ 2 periodgram were low in the Antarctic midwinter. This means that there was difficulty in synchronizing to a 24‐h period in the Antarctic midwinter. In Antarctica, sleep onset and offset times were delayed mostly in the midwinter. In Japan, sleep offset time was delayed mostly around the winter solstice.

Bright light treatment for night-time insomnia and daytime sleepiness in elderly people: Comparison with a short-acting hypnotic

Abstract Night‐time bright light (BL) treatment and triazolam (0.125 mg/day) were given to three healthy elderly people in a cross‐over design. They kept a daytime sleepiness test and a sleep log, and their wrist‐activity was monitored simultaneously. Subjectively, BL increased daytime sleepiness and naps, and decreased night‐time sleep. Triazolam decreased daytime sleepiness and naps, and increased night‐time sleep. Actigraphic night‐time sleep and naps on the first day were similar to these results. However, on the fourth day night‐time insomnia induced by BL had recovered, and naps were shorter than the baseline. Triazolam increased actigraphic naps as the days passed.

A case of aqueduct stenosis in adults with various neurological and psychiatric symptoms

SummaryA case of aqueduct stenosis in an adult with several depressive episodes and the clinical features of delusional depression is presented. The patient complained of a strange feeling in the throat. She also had had several falls with loss of consciousness. The relationship between aqueduct stenosis and diencephalic dysfunction is discussed.

Photic and Bemegride Activation of Triphasic Waves in Portal‐Systemic Encephalopathy

Photic stimulation from 0.5 to 20cps flickers was given on 7 cases of portal‐systemic encephalopathy. The triphasic waves were increased by the stimulation (mostly appearing synchronously with 2.0–3.5 cps of flicker) in all cases at least more than once in repeated EEG examinations.