CASE EXAMPLE
Data source (meeting abstract): Singer CM, Lewy AJ. Case report: use of the dim light melatonin onset in the treatment of ASPS with bright light. Sleep Res. 1989;18:445.
The experience of a 38-year-old woman with a lifetime history of ASPS illustrates the potential use and limitations of evening light treatment. Patient K.W. was a mildly hypomanic high achiever without a seasonal pattern, who typically fell asleep at about 9:00 PM and woke up between 2 and 4 AM, a pattern that led to marital stress. She could remain awake for occasional late-evening engagements, compensating with delayed time of arising at 5 to 6 AM. At baseline, she showed an early melatonin onset, at about 7:45 PM (Fig. 1). Light exposure at 2500 lux for up to 2 h beginning at 8 PM hardly affected sleep phase or melatonin onset, whereas light exposure beginning at 9 PM succeeded in maintaining sleep onset at about 11 PM and wake-up between 4 and 5 AM, which was accompanied by a 1-h delay in melatonin onset.
Advanced Sleep Phase Syndrome. ASPS, in which sleep onset occurs in the evening with awakening well before dawn, would seem to provide a counterpart to DSPS, treatable with late evening light,57 but such treatment has not been extensively investigated. Light presented in the first part of the subjective night is known to elicit phase delays in the onset of nocturnal melatonin secretion58 and the decline of body temperature,59 which might induce later sleep onset. Although ASPS is not strictly age-related, it is more prevalent among the elderly, whose early rise times are a common cause of concern. Campbell et al.60 compared the effects of evening bright light exposure (more than 4000 lux for 2 h) with a dim red light control in elderly subjects with histories of sleep maintenance insomnia. The bright light group showed improved sleep efficiency; after 12 days of treatment, nighttime wakefulness was reduced by about 1 h. Despite this benefit, most subjects were reluctant to continue treatment, given the long exposure sessions and glare discomfort. These drawbacks might be corrected with shorter exposures to higher-intensity light with the use of an apparatus that minimizes short-wavelength blue glare (see Apparatus), which is exacerbated in elderly people due to normal clouding of the lens and ocular media.
If your MEQ score is between 70-86, you fall into the range of definite morning chronotype, waking up as early as 4:00 AM (0400 h) and ready for sleep as early as 9:00 PM (2100 h); your primary goal may be to shift later. If you fall asleep even earlier than 9:00 PM (2100 h) and wake up alert before 4:00 AM, your morningness is so extreme that the questions cannot produce an accurate score. You may fall into the Circadian Rhythms Sleep Disorder, Advanced Sleep-Phase Type diagnostic category. Therefore, morning light therapy shortly after waking up — typically recommended for people with depression — will not solve your problem the way it can for later sleepers.
However, you can explore using evening light to help get your sleep into sync with day and night. You will need to find an effective light therapy dose — intensity and session duration — that provides increased alertness in the evening, moving your sleep onset into the range of morning types (ready for sleep between 9:00 PM (21:00 h) – 10:45 PM (22:45 h). You will want to avoid an extreme response to evening light that keeps you up all night or most of the night. The typical morning dose for people with depression is 10,000 lux for 30 minutes. You might start with a 15-minute exposure taken 30 minutes before your habitual bedtime. Determine the increase in energy that allows you to stay up later. If you become so energized that you can’t fall asleep for several hours, stop for a few days before continuing with a lower dose of evening light that provides an acceptable bedtime. For a milder reaction, there are three approaches:
- Take the light earlier in the evening.
- Reduce the session duration from 15 minutes to 8 minutes.
- To reduce the lux level, sit 6-12 inches (15-30 cm) farther from the light box. (The farther you sit, the lower the dose.)
On the other hand, if you have no response to a 15-minute exposure half an hour before you are ready for sleep, explore increasing the light therapy dose. You can increase the exposure time from 15 to 20-30 minutes or schedule the session 15 minutes closer to bedtime.
If you attempt self-treatment of delayed sleep phase, keep a daily log of the dose and your reaction. You can share this with a coach or clinician to follow your progress and supervise adjustments in dose and timing. If the light therapy makes you high or prevents falling asleep all night, you should seek immediate assistance.
