An automated analysis of REM sleep in primary depression.

The REM sleep of 23 nonpsychotic patients with primary depression was studied by means of an automated REM analyzer during a drug-free period and again during amitriptyline administration. Initial drug administration (50 mg) was associated with an immediate reduction in the number, average frequency, and average size of the rapid eye movements. The average REM size remained suppressed with continued drug administration while the average REM frequency showed a rebound which was responsible for a partial recovery of the number of REMs and total REM intensity to predrug levels. With regard to individual REM periods, REM frequency and REM intensity were redistributed during tricyclic administration so that the second REM period became more "intense" than the first REM period. This automated REM analysis technique provides an objective set of measures for characterizing discrete aspects of REM sleep during a depressive episode and for evaluating the changes in REM sleep during psychotropic trials.

The relationship between wrist-monitored motor activity and serum CPK activity in psychiatric in-patients.

Motor activity, monitored by a wrist motion transducer, was related to serum CPK activity the following morning in a group of psychiatric in-patients. In 4 of 10 patients, studied for periods exceeding one week, total 24-hour activity was significantly correlated with morning serum CPK activity. Motor activity during the night was unrelated to serum CPK activity. In a larger group of 30 patients, studied for one or two-day periods, inter-individual differences in activity level were not related to serum CPK activity, although both sex and race were significantly related to variance between subjects in that activity.

EEG sleep in primary depression. A longitudinal placebo study.

Characteristic EEG sleep changes in depression are highlighted by a sleep continuity disturbance, delta sleep reduction, and a shortened REM latency. Since these findings have been derived primarily from only a few baseline recordings, questions regarding their persistence and/or variability have not been previously addressed. As part of an extensive set of investigations of EEG sleep in depression, we examined nightly the sleep of 12 hospitalized, non-delusional, primary depressives who were involved in a program of active psychosocial treatment intervention and received only placebo during a 5-week study period. EEG sleep findings revealed a relative lack of change across time, particularly in those parameters reported to be associated with a primary or 'biologic' depressive episode. While some degree of clinical improvement was noted, the group failed to achieve a state of remission or even partial remission as determined by the Hamilton Rating Scale. It appears that the major sleep alterations associated with such disorders persist for up to at least 5 weeks in the absence of pharmacologic or other somatic intervention.

An objective measure of physical activity for epidemiologic research.

The development of a device is reported called the Large-scale integrated Motor Activity Monitor to examine physical activity during individuals' normal daily lives. The unit which is slightly larger than a wrist watch records body movement when worn at various body locations. Two population studies were conducted to evaluate the units. Experiment 1 examined 20 male graduate students for a two-day period. The data indicated that the units were sensitive to individual differences in physical activity and did not interfere with normal activities. Experiment 2 compared 10 Physical Education majors with 10 non-Physical Education majors by having individuals log activities and record movement counts for a two-day period. The movement data revealed that the monitors significantly discriminated between the two populations. The energy expenditure derived from the specific loggings was highly related (r = +.69) to the trunk movements, indicating that the movement counts are an accurate estimate of physical activity. The high relationship to energy analysis, the sensitivity of the units and the ease of implementation indicate that the units may be useful in relating normal activity to acute heart disease and to risk factors such as obesity and lipoproteins.

Computerised measures of electro-oculographic activity during sleep.

Since electro-oculographic (EOG) activity during human sleep appears to be of medical diagnostic and prognostic value, the vast amount of EOG data representative of even a single night's sleep warrants the development of automated pattern recognition and information extraction techniques. Such a technique for the analysis of sleep EOG rapid eye movement (REM) is presented in which the time of occurrence, area, height, duration and binocular symphrony for each REM are measured. This automated technique for sleep EOG analysis is currently used in the investigation of periodicities and values of REM parameters for normal subjects and in the differential diagnosis of affective disorders.

Rapid eye movement sleep cycle, clock time and sleep onset.

The phase of the REM sleep rhythm was studied in 10 normal subjects each of whom was sleep studied for 4 consecutive nights. For analysis, each night of sleep was aligned according to clock time and each minute was scored as REM or non-REM. With these data, REM probability was found as a function of clock time. Fractional harmonic analysis indicates a 90 min periodicity. The REM probability curve shows peaks occurring at 1:30 a.m., 3:15 a.m., 4:30 a.m., 5:45 a.m. and 7:00 a.m. Statistical measures comparing the time of REM sleep across subjects suggests that subjects tend to have REM sleep at the same time of the night as each other. The influence of elapsed time after sleep onset on REM sleep is also reestablished. Results indicate that the time of REM sleep is determined by both clock time and time of sleep onset, suggesting two clocks, one sleep dependent and the other related to the basic rest activity cycle (BRAC), which are responsible for driving REM sleep. Furthermore, the similarity of REM times across subjects indicates the possible existence of an extra-personae REM driving force linked to clock time and possibly the BRAC.

REM sleep in primary depression: a computerized analysis.

REM sleep in 35 inpatients with primary depression was automatically analyzed for 7 consecutive nights during placebo administration. For the total night of sleep, as well as each individual REM period, the number of REMs, their total voltage integral over time, the sum of their durations and the average REM size were automatically calculated. Validity of these automated REM measures was established by significant correlations with manually scored REM measures. Changes in REM sleep across the night were also investigated. Similar to findings in normal subjects, REM time did not change from REM period to REM period. Average REM size increased significantly from REM period 2-3 and 3-4. Contrary to what is seen in normal subjects, REM frequency was high during the first REM period, significantly decreased from the first to second REM period and then remained constant. Finally, a significant inverse correlation between REM frequency for the first REM period and REM latency was noted. This pattern of REM sleep is interpreted as indicating a high pressure for phasic REM at the beginning of the night which is dissipated by the first REM period.

The application of EEG sleep for the differential diagnosis of affective disorders.

On the basis of two EEG sleep criteria, REM latency and REM activity, the authors achieved 81% accuracy in distinguishing between 47 patients with primary depression and 48 patients with secondary depression using discriminant analysis. Sleep efficiency, the percentage of delta sleep, and the percentage of REM sleep discriminated between psychotic and nonpsychotic subgroups in the group with primary depression with 75% accuracy. REM activity and intermittent nocturnal awakening accurately discriminated two subtypes of patients with secondary depression at a level of 81%. These results suggest that EEG sleep measurements can yield significant data to aid in differential diagnosis in psychiatry.

Amitriptyline and EEG sleep in depressed patients: I. Drug effect.

The paucity of studies on the tricyclic antidepressants led us to conduct an investigation on 30 drug-free patients treated with amitryptyline in a double-blind protocol over a 4-week period. Consistent with previous reports, there was an immediate REM suppression on 50 mg, which was more pronounced at the 100-mg level. However, no significant incremental changes were noticed on 150 or 200 mg with regard to REM sleep suppression. Drug administration was associated with changes in other sleep variables such as stage 1 percent, stage 2 percent, and various measures of sleep continuity. The incomplete tolerance of the drug on certain REM sleep variables enhances our understanding of amitryptyline effects on the EEG sleep of depressed patients.

Telemetric motor activity in children. A preliminary study.

A lightweight telemetric mobility sensing system was used to study the relationship between high levels of motor activity during free-play and school performance. Among the 21 normal children, there was a significant correlation between high ankle motor activity during free-play, poor school achievement, the presence of neurological soft signs, and a poor self-image. Those normals whose free-play ankle activity was above the mean, also had significantly more errors and performed at a significantly lower level on the Bender Visual Motor Gestalt Test than children whose activity was below the mean. This preliminary study suggests that the telemetric mobility sensing system can be easily applied to children to assess clinically relevant components of psychomotor activity.

Rapid eye movement sleep density. An objective indicator in severe medical-depressive syndromes.

The electroencephalographic sleep patterns of 12 patients with a final diagnosis of primary depression and those of 12 patients admitted to the Clinical Research Unit with this diagnosis, but subsequently also found to be suffering from severe medical disease, were compared. Patients with depression concurrent with severe medical disease have significantly less phasic conjugate rapid eye movement (REM) activity during REM sleep than subjects with the diagnosis of a primary depression. These findings suggest that quantification of REM density may be used clinically to distinguish between medical-depressive syndromes and primary affective disorders.

Objective measurement of human motor activity: a preliminary normative study.

Motor activity values have been generated for a population of young adult subjects in order to develop normative values for motor activity levels. Using the large-scale-integrated (LSI) motor activity monitor, day and night motor activity have been continuously and noninvasively monitored for approximately 1 month on 13 normal subjects. Comparisons between measured and self-rated motor activity tend to validate this technique. The results are discussed in relation to ongoing motor activity studies showing definite changes in activity associated with fluctuations in mood and anxiety.