Dementia with Lewy bodies and AD are not associated with occipital lobe atrophy on MRI

Dementia with Lewy bodies (DLB) is associated with occipital changes in blood flow and metabolism, but structural changes in this region have not previously been assessed. The authors performed volumetric MRI measurement of the occipital lobe blind to the diagnosis in 23 subjects with DLB, 25 with AD, and 24 age-matched control subjects. There were no significant differences between groups in occipital lobe volume. The authors conclude gross structural changes in the occipital lobe do not occur in patients with mild to moderate DLB or AD.

The effect of stimulants on nocturnal motor activity and sleep quality in adults with ADHD: an open-label case-control study

OBJECTIVE

Sleep disturbances are common in adults with attention-deficit/hyperactivity disorder (ADHD). In a case-control study, adult ADHD was associated with increased nocturnal motor activity and reduced self-perceived quality of sleep.

METHOD

Eight adults with DSM-IV-diagnosed ADHD (combined type, N = 7; inattentive type, N = 1) were treated with stimulants in open-label form at 8:00 a.m., 12:00 noon, and 4:00 p.m. The mean daily dose was 51 mg of methylphenidate (range, 30-90 mg) in 7 subjects and 30 mg of dextroamphetamine in 1 subject. Actimeters were used to assess nocturnal motor activity during 6 consecutive nights both at baseline and after 3 weeks of treatment. The data were compared with those of 8 matched normal controls.

RESULTS

ADHD patients slept worse and showed significantly higher nocturnal motor activity at baseline compared with controls. No baseline differences between patients and controls were found in sleep latency, number of awakenings, and total time in bed. Changes from baseline to week 3 within the ADHD patients indicated improvement of sleep quality (p = .05) and reduction of Activity Level (p = .10) and Movement Index (p = .07) scores. When within-group changes were compared between ADHD subjects and controls, treatment with stimulants tended to be associated with a reduction of Activity Level (p < .01) and Movement Index (p = .04) scores and improved sleep quality (p = .02) in ADHD patients. Sleep latency, number of awakenings, and total time in bed were unaffected in within-group and between-group analyses.

CONCLUSION

The results should be interpreted cautiously given the open-label design and small sample size. Further study is warranted into the influence of stimulants on sleep in larger samples of ADHD patients by using controlled designs, multiple dose levels, and polysomnographic measures.

Clinical aspects of multifocal or generalized tonic dystonia in reflex sympathetic dystrophy

The authors describe 10 patients with reflex sympathetic dystrophy that progressed to a multifocal or generalized tonic dystonia. The neuropsychologic profile was similar to that of other patients with chronic pain, irrespective of its cause. The distribution pattern of dystonia, the stretch reflex abnormalities, and the worsening of dystonia after tactile and auditory stimuli suggest impairment of interneuronal circuits at the brainstem or spinal level. Antibody titers for glutamic acid decarboxylase, tetanus, and Sjögren antigens were all normal.

Quantitative assessment of daytime motor activity provides a responsive measure of functional decline in patients with Huntington's disease

Voluntary motor impairment is a functionally important aspect of Huntington's disease (HD). Therefore, quantitative assessment of disturbed voluntary movement might be important in follow-up. We investigated the relation between quantitatively assessed daytime motor activity and symptom severity in HD and evaluated whether assessment of daytime motor activity is a responsive measure in the follow-up of patients. Sixty-four consecutive HD patients and 67 age- and sex-matched healthy controls were studied. Daytime motor activity was recorded using a wrist-worn activity monitor that counts all movements during a period of five consecutive days. Patients were rated clinically for voluntary motor impairment, dyskinesias, posture & gait, depression, cognitive impairment and functional capacity. Follow-up was available from 40 patients (mean follow-up 2.0 years) and 29 controls (mean follow-up 5.9 years). Despite chorea, patients had less daytime motor activity than controls (P < 0.005). This hypokinesia correlated with impaired voluntary movements (r = 0.37; P < 0.01), disturbed posture & gait (r = 0.38; P < 0.005) and especially with reduced functional capacity (r = 0.51; P < 0.0005). During follow-up, hypokinesia remained unchanged in clinically stable patients, but became worse in those whose functional disability progressed (P < 0.005). Hypokinesia seems a core symptom of HD which is related to functional capacity. Actimetric assessment of hypokinesia is responsive to disease progression and can be used as an objective tool for follow-up.

The influence of ergotamine abuse on psychological and cognitive functioning

Migraine patients abusing ergotamine often have chronic daily headaches associated with tiredness, sleep and memory disturbances, and reduced general well-being. We quantified psychological and cognitive functioning in 12 migraine patients with and 12 without ergotamine abuse (> or = 5 days/week for > or = 6 months) and 12 healthy controls. Psychological functioning assessed by Symptom Checklist-90 (SCL-90) and Profile Of Mood State (POMS), was impaired in ergotamine abusers compared to healthy controls. Cognitive functioning divided into four domains: attention (critical flicker frequency analysis and mental control subscale of the Wechsler Memory Scale (WMS), speed of information processing (reaction time tasks and lexical decision tasks), memory (four subscales of the WMS) and cognitive flexibility (trailmaking test and WMS digits backwards), was impaired in ergotamine abusers in speed of information processing and cognitive flexibility. These differences disappeared after correction for total SCL-90 scores. In conclusion, ergotamine abuse is associated with high psychological distress but not with structural impaired cognitive functioning.

The prevalence of clinically significant sleep apnoea syndrome in The Netherlands

BACKGROUND

Figures for the prevalence of sleep apnoea syndrome range from 0.3% to 8.5%. These widely ranged estimates are probably due to differences in the definitions used, study designs, and study populations. A study was undertaken to determine the lower limit of the prevalence of clinically significant sleep apnoea syndrome.

METHODS

A cross sectional survey by postal questionnaire was carried out in a general practice of a small town in which three doctors serve 93% of its population of 6747 inhabitants of all ages. All men aged 35 and over and women aged 50 and over were invited to fill in a specially designed questionnaire on snoring and sleep. All men and women whose answers suggested the possible occurrence of sleep apnoea were invited to undergo further investigation. Oronasal thermistry was performed in the subjects' homes and the results were scored to provide an apnoea index (AI). Those subjects with an AI of > or = 5 were referred to a sleep laboratory for investigation by polysomnography.

RESULTS

Of the 2466 questionnaires issued, 2182 (88.5%) were completed and returned. The occurrence during the previous three months of regular snoring, together with daytime sleepiness and/or partners' observation of interruptions in breathing at night, was reported by 194 subjects (169 men, 25 women). In 173 subjects oronasal thermistry applied in their homes provided satisfactory recordings and, of these, 24 men and one woman had an AI of > or = 5. Analysis of the polysomnographic findings showed that 14 men and one woman met the criteria for sleep apnoea syndrome. Scrutiny of their case records disclosed that in seven men this was clinically significant.

CONCLUSIONS

Our findings suggest that the prevalence of clinically significant sleep apnoea syndrome in men aged 35 and over is at least 0.45%. Extrapolation to the population of the Netherlands suggests that at least 16,000 men suffer from sleep apnoea syndrome that should be relieved by medical care. A large proportion of these subjects remains to be diagnosed.

Bradykinesia and hypokinesia in Parkinson's disease: what's in a name?

Because in the literature bradykinesia and hypokinesia are frequently confounded, we assessed the relation between these two fundamental aspects of altered movement and the influence of disease severity on these measures in 41 patients with Parkinson's disease (PD) and 24 age-matched healthy controls. Bradykinesia was measured with a test microcomputer interfaced with a response-board. Hypokinesia was assessed by activity monitoring at home over a period of 5 successive days. For each subject the choice reaction time and measures reflecting bradykinesia (tap rate, movement time) and hypokinesia (movement index, duration of immobility periods) were calculated. Patients with PD had a normal choice reaction time and a significantly impaired execution of voluntary movement and reduced amount of movement over time. Bradykinesia was clearly present in the less affected patients with PD, and worsened as the disease severity increased. Hypokinesia, however, emerged prominently only in the more affected patients. There was a striking lack of relation between the measures that reflect bradykinesia and hypokinesia. The use of levodopa or dopamine agonists did not confound these findings. Our findings show the very different character and course of two tiers of altered movement in patients with PD and question the causative mechanisms of both motor features in PD. A more precise use of the terms brady- and hypokinesia is a prerequisite for future studies that attempt to provide insight in the causative mechanisms of both motor features.

Long-term ambulatory monitoring of urine leakage in the elderly: an evaluation of the validity and clinical applicability of thermistor signalling

This study evaluated the validity and applicability of a low-cost Urine Leakage Recording Device (ULRD) in a geriatric setting. The ULRD consisted of a thermistor, connected to a portable, digital datalogger. The thermistor was positioned on a commercially available adult diaper. Five healthy females were instructed to void urine in seven behavioural conditions comprising general motor activity patterns of the average, psychogeriatric elderly in-patient. Voids were verbally indicated by the subjects and concomitantly recorded by the ULRD and the observer. After comparing the ULRD records--scored by three independent assessors--with the subjects' reports, on average (SD) 5.3 (0.6) of a total of 10 voids were classified correctly, whereas 9.3 (1.3) false positive events were indicated. None of the subjects reported any inconvenience as a result of the recording procedure. Although the ULRD is easily applicable, we conclude that it seems to be of little value in its present form as a method for long-term ambulatory monitoring of urine leakage.

Sleep scoring at a lower resolution

Sleep scoring of whole-night polysomnograms is labor intensive. Scoring fewer epochs saves labor at the cost of accuracy; this study investigates the trade-off between the two. Whole-night sleep measures of 12 patients with sleep apnea syndrome, 10 patients with narcolepsy, and 35 controls were first computed using conventional successive 30-second epochs. Using the resulting list of sleep stages, a variable number of epochs was skipped among remaining epochs; the measures were recomputed for the reduced lists. The Bland-Altman analysis was used to define the agreements among the sleep measures at the conventional resolution and those at the lower resolutions. Scoring one-half to one-third of the number of epochs changes the duration of sleep stages only up to 2.5% and 5%, respectively, for all groups and sleep stages. In apnea patients, rapid eye movement (REM) latency deviates < 15 minutes when half of the epochs are scored. In controls and narcoleptics, much lower resolutions can be used before reaching the same level. Potential restrictions for the application of the method are discussed.

45-hour continuous quintuple-site actimetry: relations between trunk and limb movements and effects of circadian sleep-wake rhythmicity

Diurnal and nocturnal trunk and limb motor activity of 20 healthy individuals was evaluated by actimetry for 45 consecutive hours. Sleep was assessed by sleep logs. Overall, motor activity significantly (p < .05) decreased in the order wrist, ankle, and trunk. There was significantly more motor activity in the dominant wrist during the diurnal period. Motor activity was significantly affected by the 24-hr sleep-wake cycle, with lower levels and prolonged immobility during the night. Time series analyses revealed different but significant correlations between motor activity at all sites. These data imply that (a) motor activity should be recorded at the dominant wrist when the highest level of motor activity is of importance, (b) recordings at the nondominant wrist are better indicators of trunk movement than are dominant wrist recordings, and (c) sites other than the conventional nondominant wrist recording site should be evaluated to improve the validity of motor activity-based sleep-wake scoring.

Subjective sleep characteristics of 1,485 males and females aged 50-93: effects of sex and age, and factors related to self-evaluated quality of sleep

BACKGROUND

This epidemiologic study cross-sectionally examined the effects of sex and age on subjective characteristics of sleep and the factors related to self-evaluated sleep quality in a Dutch noninstitutionalized elderly population.

METHODS

1,692 sleep questionnaires were mailed to all attenders of the general practice serving Krimpen aan de Lek, The Netherlands, aged 50 or over. Both target population and responders (1,485 subjects) were virtually representative of the Dutch population regarding sex and age (50 +) characteristics.

RESULTS

Overall, females reported significantly poorer quality of sleep, longer sleep latencies, more nighttime awakenings, less frequent napping, and more frequent use of sedative-hypnotic drugs when compared to males. Additionally, there was a female predominance in the prevalence of disturbed sleep onset and sleep maintenance, whereas a male predominance was observed in the prevalence of excessive daytime sleepiness. Across subjects, a significant age-related increment was found for sleep latency time and time spent in bed. The number of nighttime awakenings increased significantly with age only in males. No significant correlations were found between health status and sex, age, or subjective sleep quality. The most frequently reported causes of disturbed sleep onset and sleep maintenance were worries and nocturia, respectively. Subjective quality of sleep was mostly associated with self-estimated sleep latency.

CONCLUSIONS

Our findings extend those of previous epidemiologic studies reporting that sleep disorders are common in the general elderly population. Future studies should further elucidate the nature and extent of geriatric sleep disorders to satisfy the increasing need for its accurate diagnosis and treatment.

Hypokinesia in Parkinson's disease: influence of age, disease severity, and disease duration

The aim of this cross-sectional study was to compare the role of aging in measures reflecting diurnal activity and immobility in 60 parkinsonian patients with predominant features of hypokinesia and rigidity and 100 healthy subjects aged 50 to 98 years. In the patients, we also studied the relation between disease duration and subjective and objective measures of disease severity. Motor activity was recorded during 5 successive days at home with a wrist-worn activity monitor. For each subject, two mean measures reflecting the diurnal activity level and the relative proportion of activity and immobility were calculated. Diurnal measures of activity revealed in both groups a prominent absolute reduction of activity and an increase of the time spent without movement ("immobility") with advancing age. Parkinsonian patients showed significantly lower values for both motor-activity measures than did the healthy subjects. The rate of the age-related decline of both diurnal activity measures in both groups, however, is comparable. Disease duration showed no relation with subjective and objective measures reflecting disease severity. This study shows that if care is taken to control for disease severity, the rate of the age-related decline of measures reflecting diurnal activity and immobility is similar in both groups. The lack of relation between disease duration and subjective and objective measures of disease severity suggests that the rate of progression of Parkinson's disease can be reliably studied only by means of longitudinal studies.

Circadian distribution of motor activity and immobility in narcolepsy: assessment with continuous motor activity monitoring

The circadian distribution of motor activity and immobility of 14 unmedicated narcoleptics and matched controls was evaluated by monitoring continuous wrist motor activity 5 successive days and nights at home. Sleep was also assessed by sleep logs. The amplitude of the circadian rhythm of motor activity and immobility was significantly lower in narcoleptics than in controls. The variables that best distinguish narcoleptics from controls were the diurnal and nocturnal mean duration of uninterrupted immobility, which can be explained by excessive daytime sleepiness and frequent nocturnal awakenings, respectively. Thus, measures of diurnal and nocturnal motor activity and immobility appear useful for the objective assessment of some of the sleep-wakefulness manifestations of narcolepsy.

Wrist actigraphic assessment of sleep in 116 community based subjects suspected of obstructive sleep apnoea syndrome

BACKGROUND

The combined use of wrist actigraphic assessment and self assessment of sleep in the screening of obstructive sleep apnoea syndrome was evaluated in a community based sample.

METHODS

One hundred and sixteen community based subjects clinically suspected of having obstructive sleep apnoea (syndrome) were evaluated by means of simultaneous ambulatory recording of respiration (oronasal flow thermistry), motor activity (wrist actigraphy), and subjective sleep (sleep log) during one night of sleep.

RESULTS

The subjects were distributed according to their apnoea index (AI); AI < 1 (non-apnoeic snorers) 44%; AI 1- < 5 39%; and AI > or = 5 17%. High apnoea index values were associated with self reported disturbed sleep initiation and more fragmented and increased levels of motor activity and decreased duration of immobility periods, particularly in those with an apnoea index of > or = 5. Across subjects the duration of immobility periods was the only predictor of the apnoea index, explaining 11% of its variance. Use of the multiple regression equation to discriminate retrospectively between those with an apnoea index of < 1 and > or = 5 resulted in sensitivity and specificity values of 75% and 43%, and 5% and 100%, respectively.

CONCLUSIONS

The combined use of a sleep log and actigraphic assessment of sleep failed to identify reliably those subjects who suffered from obstructive sleep apnoea (syndrome) in a sample of community based subjects reporting habitual snoring combined with excessive daytime sleepiness and/or nocturnal respiratory arrests.

Sleep disruption in Parkinson's disease. Assessment by continuous activity monitoring

OBJECTIVE

To assess differences in activity and immobility during sleep between patients with Parkinson's disease (PD) and healthy subjects and to evaluate the relations of clinical variables with the motor activity measures in patients with PD.

DESIGN

Survey, case series.

SETTING

University hospital outpatient neurology department and urban population in Leiden, the Netherlands. Motor activity was recorded during 6 successive nights at home with a wrist-worn activity monitor.

PARTICIPANTS

Eighty-nine patients with PD and 83 age-matched healthy controls.

MAIN OUTCOME MEASURES

For each subject, three mean measures reflecting activity or immobility during the nocturnal period were calculated.

RESULTS

Compared with the healthy elderly subjects, patients with PD have an elevated nocturnal activity level and an increased proportion of time with movement, indicating a more disturbed sleep. The mean duration of nocturnal immobility periods was similar for both groups. This measure, however, did reflect the self-reported disturbed sleep maintenance in both groups. The daily dose of levodopa or the use of dopamine agonists in patients not receiving levodopa, rather than disease severity, proved to be the best predictors of nocturnal activity.

CONCLUSIONS

We hypothesize that in mildly to moderately affected patients with PD, levodopa or dopamine agonists cause sleep disruption by their effects on sleep regulation. In more severely affected patients, the beneficial effects of these drugs on nocturnal disabilities that cause sleep disruption in PD prevail.

Sleep and ageing: the effect of institutionalization on subjective and objective characteristics of sleep

To assess the impact of institutionalization on sleep/wake characteristics of elderly people, we compared subjective (study I: n = 160) and objective (study II: n = 30) sleep/wake measures of non-demented institutionalized subjects and age-matched non-institutionalized controls. We also evaluated the prevalence and causes of various sleep disturbances. The three living conditions, i.e. independently living (IL), service home (SH) and nursing home (NH) were respectively assumed to have minimal, moderate and maximal effects upon the timing, the amount and the quality of the sleep/wake behaviour of the persons involved. Study I showed that a higher level of institutionalization was significantly (p < 0.05) associated with phase-advanced sleep/wake patterns, increased amounts of time spent in bed during the 24-hour period and increased usage of prescribed sedative-hypnotic drugs. Poor sleep quality and disturbed sleep onset occurred significantly mostly in the SH group. No differences between groups were demonstrated with respect to the prevalence of disturbed sleep maintenance, parasomnias and difficulty with awakening and their possible causes, except for environmental noise which was exclusively reported by institutionalized subjects. No differences between groups for any of the objective measures were found (study II). Overall, our findings are in line with previous findings on this topic, although the observed high rate of poor sleep quality and sleep disturbances and their associated causes as observed in institutionalized subjects also occurs in an age-matched non-institutionalized population.

The clinimetrics of hypokinesia in Parkinson's disease: subjective versus objective assessment

In this study we evaluate the feasibility of measures that reflect different characteristics of motor activity and immobility in the objective quantification of hypokinesia. Because by definition hypokinesia can only be assessed over a period of time, continuous activity monitoring was used during 5 successive days in the home setting in 64 patients with Parkinson's disease (PD) and 104 healthy elderly subjects. In the patients we also evaluated the relation between the monitor measures and subjective measures of hypokinesia and age. Compared to the healthy elderly subjects, PD patients have a decreased activity level, increased proportion of time without movement, elevated mean duration of immobility, and decreased percentage of short-lasting immobility periods. Differences between both groups were most prominent for those measures that incorporate or reflect immobility. Moreover, in the PD patients the mean duration of immobility and percentage of short-lasting immobility periods show an apparent lack of relation with age and clinical ratings obtained from the UPDRS. In conclusion, our findings underscore the poor representation of hypokinesia in the UPDRS and value of objective quantification of this fundamental impairment of PD.

Where to record motor activity: an evaluation of commonly used sites of placement for activity monitors

The aim of this study was to evaluate the role of the site of attachment of activity monitors. We compared mean diurnal and nocturnal motor activity measures as well as the daily pattern of motor activity of dominant and non-dominant wrist recordings over 5 successive days of 10 healthy right-handed and 10 left-handed subjects. In a second study we evaluated the relationship between truncal motor activity and wrist motor activity. No differences emerged between the diurnal and nocturnal measures as well as the diurnal activity pattern of the dominant and the non-dominant wrist. Additionally, no differences were found in relation to handedness. Our results show that it is inaccurate to regard wrist motor activity measurements as representative of an invariable percentage of truncal motor activity; the relation between the measurements of these two recording sites varies across the daytime period. During the nocturnal period bilateral wrist motor activity occurred frequently in absence of truncal motor activity. The reverse situation, however, may occur sporadically. This finding most likely reflects that integrated generalized movements like postural shifts are measured at all recording sites, while the small movements that occur at the distal extremities are predominantly recorded by wrist-worn monitors. In conclusion, it is apparent that for both diurnal and nocturnal studies on the assessment of motor activity, either wrist can be chosen as the recording site. Across the diurnal period the relation between motor activity recorded at the wrist and waist is subject to considerable variability.(ABSTRACT TRUNCATED AT 250 WORDS)

Nocturnal activity and immobility across aging (50-98 years) in healthy persons

OBJECTIVE

To measure the influence of age on measures of nocturnal activity and immobility in 100 healthy subjects aged 50 to 98 years.

DESIGN

Cross-sectional study.

SETTING

Urban population in Leiden. Recordings were performed at home while the subjects maintained their habitual 24-hour pattern of activities.

PARTICIPANTS

100 subjects without a history of major medical disorders and a normal neurological examination and performance-oriented assessment of gait (Tinetti).

MEASUREMENTS

Motor activity was recorded during six successive nights with a wrist-worn activity monitor. The occurrence of supra-threshold motor activity was recorded over 15-second epochs. A questionnaire was used to evaluate sleep habits and the occurrence of sleep disturbances. Four mean measures reflecting activity or immobility during the nocturnal period were calculated for each subject.

RESULTS

Only one out of four measures, (ie, the nocturnal proportion of time with movement, increased with age for females. For males, no age effects emerged. The mean duration of nocturnal immobility periods was higher in females than in males. Also, for females, the use of hypnotics increased with successive decades. Sex and the use of hypnotics were significantly related to the mean duration of immobility periods.

CONCLUSION

If care is taken not to confound aging with illness, measures of nocturnal activity and immobility reveal only marginal effects of aging.

Diurnal effects of motor activity and fatigue in Parkinson's disease

Wrist motor activity was monitored continuously in 65 patients with Parkinson's disease (PD) to assess the influence of disease severity and excessive fatigue on the diurnal motor activity pattern. Mildly or moderately affected PD patients had a similar diurnal pattern to that of 68 healthy controls, with a late morning peak; however, mean levels of motor activity were lower. The most severely affected patients showed an overall flattened diurnal pattern. Results refute the existence of end of day deterioration, but instead suggest a "depressed morning start" in the most severely affected patients with PD. Excessive fatigue was not reported at a particular time of day and did not influence the diurnal motor activity pattern.

Actigraphically recorded motor activity and immobility across sleep cycles and stages in healthy male subjects

The aim of this study was to compare the extent to which activity and immobility measures are related to sleep stages and sleep cycles in order to improve the informative value of actigraphic assessment of sleep. We therefore performed simultaneous ambulatory polysomnography and wrist-activity monitoring (AM) in 14 healthy male subjects without sleep complaints. In this context, a simple method for transforming raw motor activity data into a time-series reflecting onset and duration of activity and immobility clusters is introduced. Our results demonstrate that nocturnal AM measures were significantly affected by sleep stage. Low activity levels and particularly prolonged episodes of uninterrupted immobility were associated with increasing sleep depth. On the other hand, high activity levels and prolonged episodes of activity were related to intermittent wakefulness during sleep. Our results suggest that measures reflecting the occurrence and duration of activity and immobility clusters provide a better approach in studying the relationship between activity/immobility and sleep stages. Except for the duration of uninterrupted immobility episodes, which showed a significant decrease in the fourth cycle, none of the AM measures showed a significant cycle-to-cycle variation. Consequently, mean nocturnal motor activity measures provide an accurate reflection of the total sleep period. However, none of the AM-derived measures seems useful in evaluating the cycle structure during sleep.

Assessment of response fluctuations in Parkinson's disease by ambulatory wrist activity monitoring

The aim of this study was to examine the influence of response fluctuations with dyskinesia on the 24-h motor activity pattern and measures of diurnal and nocturnal activity and immobility. Motor activity was recorded during 5 successive days in 5 patients with advanced Parkinson's disease (PD) suffering from severe response fluctuations with dyskinesia, as well as in 10 PD patients with a stable levodopa response and 10 healthy subjects. The 24-h motor activity pattern of the patients with response fluctuations provides insight into the relationship between the therapeutic regimen and 1) the frequency and duration of "on" and "off" periods, 2) the severity of the dyskinesias, and 3) the degree of sleep disruption. In accordance with the severity of their motor fluctuations, patients with response fluctuations showed a large intra- and interindividual variability of diurnal motor activity measures. Overall, the nocturnal motor activity measures in the patients with response fluctuations indicated a severely disturbed sleep when compared with the two control groups. Factors as simplicity and the potential to record unrestrained motor activity for several days continuously in all settings, make activity monitoring a welcomed acquisition in the assessment of response fluctuations in PD.

Ambulatory activity monitoring during sleep: an evaluation of internight and intrasubject variability in healthy persons aged 50-98 years

The aim of this study was to assess the internight and intrasubject variability of nocturnal activity and immobility measures of 99 healthy subjects aged 50-98 years. Motor activity was recorded at home during 6 successive nights with a wrist-worn activity monitor. The occurrence of suprathreshold motor activity was recorded over 15-second epochs. For each subject, six mean measures reflecting activity or immobility during sleep and their coefficient of variation were calculated. Our results revealed no first-night effect or day-of-week effect of the activity and immobility measures over the 6 nights across all subjects. On the other hand, for all nocturnal activity and immobility measures, a considerable intrasubject variability across the 6 nights was found. Females had a greater intrasubject variability of the mean duration of immobility periods and the movement index than males. The intrasubject variability of all nocturnal activity and immobility measures across the successive age groups remains stable. These findings emphasize that although a first-night effect may be lacking, the intrasubject variability of activity and immobility measures across several nights may still be considerable.

A new approach in the assessment of motor activity in Parkinson's disease

Motor activity was recorded continuously with a wrist-worn activity monitor for almost six days in nine patients with different predominant manifestations of Parkinson's disease and 10 normal subjects. The indices of diurnal motor activity decreased with the progressive worsening of hypokinesia and rigidity. With this monitor and a simple diary it was possible to determine the contribution of a moderate resting tremor and choreiform dyskinesias to the motor activity level, and to monitor their variability.