The effects of bright light and physical activity at circadian rhythm disturbances in persons with MCI.

Sleeping problems are frequently reported in the older non-demented population
and in patients with Alzheimer*s Disease (AD). Mild Cognitive Impairment (MCI)
might be a relevant marker to examine pre-AD processes, and since
disconnections of suprachiasmatic nucleus (SCN) structures appear from
preclinical stages of AD onwards, MCI is an interesting research field in order
to prevent or delay further neurodegeneration. Light and physical activity both
influence the circadian rhythm system, but their interactions are complex and
not frequently investigated yet. Nevertheless, research reports and theoretical
frameworks are promising considering improvements in sleep-wake cycle and the
rest-activity rhythm with light treatment or physical exercise. Therefore it is
important to investigate the complex interactions of light and physical
activity on the circadian rhythm system, especially in persons who are already
suffering from decline in structures involved in the circadian rhythm system as
observed in MCI patients

The objective of the study is to investigate the effects of bright light
combined with physical activity during the morning on subjective and objective
outcomes related to sleep-wake cycle and the rest-activity rhythm in persons
with MCI, aged 65 years or older and having at least one sleeping problem.

A randomized control trial will be used to investigate the effects of bright
light and physical activity on sleep-wake and rest-activity parameters in older
persons with MCI. There will be four groups: morning bright light, morning
physical activity, morning bright light combined with physical activity or no
treatment, wait list control, group. Participants will be assessed by using two
short questionnaires: The 5-item Athens Insomnia Scale (AIS-5) to assess the
presence of sleeping problems and the PAR-Q to screen for medical risks.
Included persons will be randomly assigned to one of the four treatment groups.
After that, questionnaires will be assessed to control for confouning factors.
To control for comorbidities, a comorbidity questionnaire of Van den Berg & Van
den Bosch (1989)will be assessed. Depression will be assessed by the 30-item
Geriatric Depression Scale (GDS-30). Anxiety will be assessed by the Geriatric
Anxiety Inventory (GAI). Frailty will be assessed by the Groningen Frailty
Indicator (GFI). The chronotype will be assessed by the Munich Chronotype
Questionnaire (MCTQ). The 6CIT will be assessed to investigate the amount of
cognitive impairment . Participants are already diagnosed with MCI, but in
order to better compare participants of this study, this short questionairre is
added. The amount of cognitive impairmant will be assessed by the Mini Mental
State Examination (MMSE). The latter is added because the MMSE is known as the
gold standard in the cognitive research area. All questionnaires are reliable
and valid.
Subjective slaap quality is assessed by the Groningen Sleep Quality Scale
(GSQS). Objective slaap quality and rest-activity outcomes are assessed by
Actiwatch, which is a wrist-worn accelerometer. During the intervention a
pedometer has to be worn to control for additional physical activity. Also a
diary/checklist to check the time spend on the intervention and to control for
additional outdoor activities during the intervention has to be filled in daily.
In order to predict maximal oxygen consumption to perform 60% VO2max intensity
exercise in de morning physical activity group and the combined morning bright
light and physical activity group, a submaximal bicycle test will be assessed.
The predicted VO2max will be calculated by the Astrand Rhyming nomogram.

There are four treatment groups:
1. morning bright light
2. morning physical activity
3. morning bright light combined with physical activity
4. no treatment group (wait list control)

Persons in the morning physical activity group will receive a home based
exercise program. The exercise sessions exists of moderate intensity endurance
training (60% VO2max) for 30 minutes each day. The 30 minutes were split up in
2 sessions of 15 minutes cycling with 10 minutes of rest in between.
Participants are free to choose the timing of their exercise training as long
as it was performed between 7 and 11am.
The morning bright light group will be exposed to 10.000 lux for one hour
between 7and 11 am. The combined morning bright light and physical activity
group will receive a home-based exercise program which should be performed in
front of the light box. After finishing the exercise program, the participant
has to sit in front of the light box for the remaining 20 minutes. In total,
the participant receives 60 minutes of bright light, of which 30 minutes during
exercise. The exercise program protocol is the same as the morning exercise
group protocol. Persons in the wait list control group will receive a morning
bright light program after termination of the study. Persons are free to choose
their own preference intervention time between 7.00am and 11.00am. Persons in
the wait list control group recive a light box to accomplish the morning light
program after termination of the study. During the intervention period of 10
days the persons of the control group recieve a pedometer to control for
physical activity. They will also be asked to fill in a diary/checklist for
additional outdoor activities during these ten days.

Participating in the DYNAMO project is of markedly burden for the participants,
but there are advantages for the participants. The burden consists of:
1. Filling in multiple questionnaires and wearing an Actiwatch for 14 days
preceding the intervention
2. One hour of one of the prescribed interventions for 10 days combined with
wearing a pedometer for the whole day. During these ten days a chacklist has to
be filled in daily to control for additional outdoor activities and the time
spend on the intervention.
3. Wearing an Actiwatch for 14 days after the intervention period
Besides, we tried to lower the load for the participants by letting the
participants choose their own preference time of the intervention, as long as
it will be performed between 7.00am. and 11.00am.
Participating in this study is of low risk, because there will be no invasive
procedures and the bright light exposure is comparable to the light intensity
on a cloudy day. The intensity and duration of the exercise intervention is in
accordance with the Dutch Recommendation for Daily Physical Activity.
The advantages consists of the direct effects of the intervention, that is
hypothesized as improved sleep outcomes and strengthening of the rest-activity
rhythm.
With the results of this study, we await to develop a relevant program to
enhance activities of daily living (ADL) and prevent circadian rhythm
disturbances of persons with MCI. This will be beneficial for the quality of
life of persons with MCI and their caregivers. In the optimal situation
hospitalization may be delayed without extra burden for the caregivers.