Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT02290405 |
Other study ID # |
2786 |
Secondary ID |
|
Status |
Completed |
Phase |
|
First received |
|
Last updated |
|
Start date |
October 1, 2014 |
Est. completion date |
December 31, 2017 |
Study information
Verified date |
May 2018 |
Source |
National Jewish Health |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Observational
|
Clinical Trial Summary
The purpose of this study is to learn more about people with insomnia disorder and cognitive
impairment. Cognitive impairment is difficulty with mental abilities such as thinking,
knowing and remembering.
Description:
Primary insomnia (PI) sufferers typically complain of such daytime impairments as reduced
attention, concentration, memory and global mental acuity. Moreover, epidemiological studies
have shown PI contributes to reduced productivity, work and traffic accidents, and serious
falls among the elderly. Despite such findings, laboratory-based efforts to corroborate the
cognitive complaints of PI sufferers have produced mixed results. Indeed, many studies
comparing PI sufferers with non-complaining normal sleepers across a range of
neuropsychological tests have failed to show any relative deficits among the PI group. Such
findings, in turn, has led to the impression that PI patients cognitive complaints may be
over-stated and result from their attentional bias toward minor cognitive errors,
dysfunctional beliefs about the impact of insomnia on functioning or excessive self focus
rather than to any measurable daytime impairment.
However, many previous such studies were underpowered due to small sample sizes and employed
neuropsychological tests designed for detecting impairment resulting from brain
disease/damage rather than the more subtle albeit significant impairments of which PI
patients complain. In recent research, we and others have shown that PI sufferers do, indeed,
show greater deficits (slower and more variable reaction times) particularly on complex
switching attention tasks. Moreover, there is some preliminary evidence that the subgroup of
PI sufferers with elevated levels of physiological hyperarousal are most prone to suffer from
neuro-cognitive performance deficits than are matched groups of PI sufferers who are not
physiologically hyperaroused and normally alert individuals without insomnia. For example,
Fernandez-Mendoza recently showed that PI sufferers with a hyperarousal pattern suggested by
their objective short sleep duration on serial polysomnograms (PSG) performed more poorly on
a complex switching attention task than did both normal sleepers and PI sufferers with normal
objective sleep durations.
In our efforts to follow up on this latter work, we recently examined the error rates of
alert and sleepy PI sufferers and normal sleepers across a series of simple and complex
reaction time tasks. We employed age and gender matched samples of PI (N=89) sufferers and
normal sleepers-NS (N=95). Participants underwent three nights of PSG followed by daytime
testing with a four-trial Multiple Sleep Latency Test-MSLT. The PI and NS groups were each
subdivided into "alert" (e.g., MSLT mean onset latency > 8 minutes) and "sleepy" (e.g., MSLT
mean onset latency < 8 minutes) subgroups to allow for testing the main and interaction
effects of participant type and level of alertness. "Alert" participants had longer MSLT
latencies than "sleepy" participants (12.7 vs. 5.4 minutes). PI sufferers had fewer correct
responses on performance testing than did NS. However, as shown by the adjacent, figure we
found a significant group x alertness interaction (p = .0013) with greater error rates
occurring among alert (hyperaroused) PI sufferers (Mean=4.5±3.6 errors per trial) than among
alert NS (Mean=2.6±1.9 errors per trial). This was particularly true for the more complex
switching attention task.
Our work along with that of Fernandez-Mendoza serve to confirm that PI sufferers have
measureable objective neuro-cognitive deficits and provide some preliminary suggestion for
the types of testing approaches that should be used to detect them. The identification of
tests sensitive to PI sufferers' cognitive deficits are particularly relevant for testing the
effects of current and future insomnia therapies on patients' objective daytime functioning.
Measures of daytime dysfunction can and should serve as endpoints for assessing benefits and
detriments of insomnia therapies. In addition, our recent work suggests that subgroups of PI
sufferers may differ in their daytime deficits, with those showing physiological hyperarousal
being most prone to make errors. This finding suggests that different types or doses of
treatment may be needed to reverse the daytime impairments of the hyperaroused and
non-aroused PI patients. However, our line of research would benefit by replication and
extension findings to (1) further confirm the detrimental effects of physiological
hyperarousal on PI sufferer's neuro-cognitive functioning; and (2) identify a broader range
of tests that can be used for assessing diurnal cognitive impairments in both physiologically
hyperaroused and lesser aroused PI groups. The current project will address these aims.