Study Design and Setting
This is a randomized controlled clinical trial in which participants (n=150) are randomized to 6 sessions of individual telemedicine-delivered Cognitive Behavioral Therapy for insomnia (CBT-TM, n=75) or Sleep Hygiene Education (SHE-TM, n=75). All participants will complete outcome assessments at baseline, immediately post-treatment, and at 3, 6, and 12 months following completion of treatment. The primary clinical outcomes will be post-treatment scores on the Insomnia Severity Index (ISI), Multidimensional Fatigue Inventory (MFI), and percentage of days abstinent, as determined using a Timeline Follow Back assessment of drinking behaviors. Post-treatment dissipation of SWA in NREM sleep (measured with the best-fit slope based on exponential regressions) will be the primary outcome to assess EEG delta activity, the marker of sleep homeostasis. The study flow is shown in Figure 1.
The study will be performed at a single site, the University of Michigan, in Ann Arbor, Michigan. The study protocol has received ethics approval from the Institutional Review Board for Medicine (IRBMED) for the University of Michigan and any future amendments to the study protocol will be reviewed by IRBMED.
Participants
A total of 150 participants will be recruited from patients receiving an episode of abstinence-based outpatient alcohol treatment and from the community via online advertisements (e.g., Facebook, Instagram). Concurrent medications and/or therapies for AUD or co-occurring psychiatric and medical conditions will be permitted. Study participants will meet all of the eligibility criteria outlined in Table 2.
Table 2: Participant Inclusion and Exclusion Criteria
Inclusion Criteria
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- 18-65 years of age at enrollment
- Meet DSM-5 criteria for Alcohol Use Disorder (AUD) with ≤12 weeks of abstinence
- Engaged in an abstinence-based alcohol treatment program
- Meet DSM-5 criteria for chronic insomnia, confirmed with sleep diary
- Reported stable residence (e.g. reliable place to sleep)
- Ability and willingness to travel to Ann Arbor for sleep laboratory assessments or to complete sleep testing at home
- For individuals taking medications to promote sleep: agree to maintain a stable regimen from time of enrollment through end of the active treatment phase
Access to a BlueJeans- or Zoom-capable device and Wi-Fi network
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Exclusion Criteria
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- Diagnosis of, or high suspicion for, sleep disorders other than insomnia
- Meet DSM-5 criteria for bipolar disorder, psychotic disorder, or PTSD
- Terminal or progressive physical illness (e.g., cancer), neurological degenerative disease (e.g., dementia), or presence of an unstable medical condition that is the specific cause of insomnia
- Previous trial of CBT for insomnia
- Self-reported pregnancy or intention to become pregnant during the study
- Other conditions and situations, medical or otherwise, that preclude meaningful and/or safe participation in CBT/SHE and study procedures
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Measures
Screening Measures
Participants are screened initially using the Insomnia Severity Index (ISI) and Alcohol Use Disorders Identification Test (AUDIT) to assess for likely Chronic Insomnia Disorder and Alcohol Use Disorder, respectively. For participants recruited in person, these measures are delivered at the initial clinic visit and will be verified via review of the electronic medical record. For participants recruited online, a separate online screening tool includes these measures and is completed to assess eligibility. Additional screening measures include the Mini International Neuropsychiatric Inventory (MINI), to confirm AUD and assess for exclusionary psychiatric conditions, and the Structured Clinical Interview for Sleep Disorders- Revised (SCISD-R) to confirm chronic insomnia diagnosis and rule out other clinical sleep disorders. The final screening assessment is polysomnography (PSG) conducted in-laboratory or at home (using the Prodigy Sleep System, Cerebra Medical, Winnipeg, Manitoba, Canada) to rule out a likely clinical sleep disorder per the International Classification of Sleep Disorders, 3rd Edition (ICSD-3) (48). Any participant with a PSG suggestive of a clinical sleep disorder other than insomnia will be withdrawn from further study participation and referred for further clinical evaluation and management.
Sleep Diary
Participants will be asked to complete the consensus daily sleep diary (49) with two additional questions about alcoholic beverage quantity and use of alcohol for sleep at the following time points:
- Baseline period (1-2 weeks before treatment) to confirm insomnia
- Throughout the duration of treatment (6 weeks)
- For one week immediately post-treatment and at 3-, 6-, and 12-months post-treatment
The Sleep Diary data will be collected daily via a web-based platform. Participants are asked to provide subjective reports of the following: bedtime, lights out time, sleep onset latency, number of nocturnal awakenings, duration of nocturnal awakenings, wake time, and rise time. Additional questions ask about alcohol use in the preceding day and will be used to monitor drinking behaviors and days abstinent.
Polysomnography
During the baseline period, participants will complete two nights of in-laboratory or at-home polysomnography (PSG); the first night of data will serve as an adaptation/screening night and the second night will be used as baseline data. Following completion of treatment, participants will be scheduled for an additional night of PSG in the same setting (in-lab or at home) to evaluate objective sleep outcomes.
For in-lab PSG, electroencephalograms (EEGs) will be placed according to the International 10-20 System and recorded from the left and right frontal, central, and occipital electrode sites (F3 & F4; C3 & C4; O1 & O2) (50); monopolar electooculographic (EOG) recordings will be made from the supraorbital and infraorbital ridges of the eyes; and the electromyogram (EMG) will be recorded from a bipolar chin-cheek montage. Electrophysiological signals will be acquired and analyzed on Compumedics Diagnostic Amplifier Systems using Compumedics Profusion SLEEP4 Online Acquisition and Analysis Software (Compumedics USA Inc., Charlotte, NC). Data will be digitized at 256 Hz and stored off-line for visual stage scoring by a trained sleep technician blinded to participant sociodemographic characteristics and treatment condition (51).
For participants who are unable or unwilling to come for in-lab PSG, especially in consideration of safe public health practices related to COVID-19, PSG will be completed at home using the Prodigy Sleep System device (Cerebra Medical, Winnipeg, Manitoba, Canada). The Prodigy Sleep System is a Class II medical device that has been approved by Health Canada and is currently seeking Food and Drug Administration (FDA) approval in the United States. Participants tested with this device will be shipped all of the materials needed to complete testing, full instructions for use, and pre-paid materials to return the device to the study team upon completion. The Prodigy Sleep System utilizes dual frontal EEG leads (F3 & F4 derivations), dual supraorbital/infraorbital EOG leads, intercostal and mental EMG leads, ECG, along with a wireless oximeter, respiratory effort belts, and nasal cannula to collect data comparable to an in-lab PSG. Electrophysiological signal data are sent to a tablet via Bluetooth, and the study team will download data from the tablet to Cerebra Medical’s Michele software, where the raw data will be manually scored by a trained sleep technician blinded to participant sociodemographic characteristics and treatment condition.
Actigraphy
Participants are asked to wear an actigraph during the baseline and for one week at each follow up visit (immediately post-treatment, 3-, 6-, and 12-months post treatment). The actigraph (Actiwatch Spectrum Plus, Philips Respironics, Bend, OR) is a small waterproof device the size of a wrist watch (48 x 37 x 14 mm weighing 30 grams) that is worn continuously on the non-dominant wrist. A solid-state piezo-electric accelerometer (range 0.5-2G peak value, sensitivity 0.025G) integrates movement frequency and intensity into a single measurement. In addition, color-sensitive photodiode sensors (range 400-700 nm) continuously monitor incoming light and store the data in lux levels. The actigraphs are set at a sampling rate of 30 seconds. Activity and light data are downloaded to computer and sleep/wake activity is estimated by Actiware®–Sleep software using published guidelines (52, 53).
Outcome Measures
Primary outcomes will be assessed in the following domains:
- Insomnia (Aim 1). Changes in insomnia severity from baseline to post-treatment will be assessed with the Insomnia Severity Index (ISI), a 7-item self-assessment of global insomnia severity that ranges from 0-28, with higher scores indicating more severe insomnia symptoms (0-7 no clinical insomnia, 8-14 mild insomnia severity, 15-22 moderate insomnia severity, 23-28 severe insomnia severity). The primary outcome from this measure is post-treatment total score. Secondary outcomes will include post-treatment and follow-up differences in the percentage of responders (ISI change score >7 relative to baseline) and remitters (post-treatment and follow-up ISI score ≤7).
- Daytime Symptoms (Aim 1). The Multidimensional Fatigue Inventory (MFI) will be the primary measure of daytime symptoms. This 20-item self-report assessment provides an overall fatigue score (20-100) in addition to 5 separate dimensions of fatigue: general fatigue, physical fatigue, reduced motivation, reduced activity, and mental fatigue. Subscale scores range from 4-20 with higher scores indicating higher levels of fatigue (54). The primary outcome from the MFI is the post-treatment general fatigue subscale score.
- Drinking Behavior (Aim 2). Changes in drinking behavior will be evaluated with the Alcohol Timeline Follow-Back (TLFB). This interviewer-administered drinking measure assesses both frequency and quantity of alcohol consumption. The primary outcome on the TLFB will be the post-treatment percentage of days abstinent. Secondary TLFB outcomes will include the percentage of heavy drinking days and drinks per drinking day (55).
- EEG Delta Activity (Aim 3). We will use a power spectral analysis (PSA) algorithm to evaluate EEG delta activity. PSA generates power (area under the curve) in five EEG frequency bands: delta (0.5 to < 4 Hz), theta (4 to < 8 Hz), alpha (8 to < 12 Hz), sigma (12 to < 16 Hz) beta (16-32 Hz), and gamma (>32 Hz), expressed in µV2. Power values are averaged across 30s epochs for each frequency band, generating data segments in identical epoch lengths to the stage-scored data (56). Power values are then sorted by sleep stage to evaluate the distribution of EEG frequencies within and across successive REM and NREM periods (57, 58). The primary outcome will be the post-treatment dissipation of SWA in NREM sleep (measured with the best-fit slope based on exponential regressions), but we will additionally evaluate SWA power in the first NREM period and averaged across the night.
To evaluate treatment-related changes in daytime functioning, we will also administer the following secondary outcome measures (See Table 3 for schedule of assessments):
- Morningness Eveningness Questionnaire (MEQ): a 19-item scale to assess participant-preferred tendencies for timing of daytime/nighttime activities and assessment of different circadian rhythm chronotypes.
- Epworth Sleepiness Scale (ESS): an 8-item scale used to assess for the severity of daytime sleepiness.
- Dysfunctional Beliefs and Attitudes About Sleep (DBAS): a 16-item scale used to identify unhelpful beliefs about sleep and insomnia.
- Generalized Anxiety Disorder (GAD-7): a 7-item scale to assess for generalized anxiety disorder symptoms.
- Patient Health Questionnaire Depression Scale (PHQ-8): an 8-item scale designed to screen for symptoms of depression. This version does not include the item to assess for suicidal ideation, which is assessed elsewhere (MINI).
- Short Form-12 (SF-12): a 12-item scale to assess participants’ perception of overall health and well-being.
- Short Inventory of Problems-Revised (SIP-R): a 17-item scale to examine the adverse consequences of drug and/or alcohol abuse.
- Penn Alcohol Craving Scale (PACS): a 5-item scale to examine frequency, duration, and intensity of alcohol cravings.
Finally, the following treatment process measures will be administered:
- Therapist Evaluation Questionnaire (TEQ): 5-item self-report scale that assesses perceived logic, confidence, and success of the treatment and participant willingness to take part.
- Working Alliance Inventory – Short Revised (WAI-SR): a 12-item measure that evaluates three aspects of therapeutic alliance – agreement on therapy goals and tasks, and development of an affective bond.
Procedures
Participants are recruited either from abstinence-based outpatient alcohol treatment programs or from the community. All participants will be scheduled for a combined consent and baseline visit, to be conducted remotely, via BlueJeans (BlueJeans Network, San Jose, CA) or Zoom for Healthcare (Zoom Video Communications, Inc., San Jose, CA), or in person, as conditions permit. Consent for audio recording of treatment sessions for treatment fidelity review, submission of data to the NIAAA Data Archive, and storage of de-identified data for unspecified future research will also be sought at this time. After the participant and team member have signed the ICF, the study team member will deliver the MINI and SCISD-R screening assessments to assess participant eligibility. After screening assessments confirm diagnoses of insomnia and alcohol use disorder, and rule out any exclusionary criteria, participants will be provided with a daily sleep diary and actigraph to maintain during the baseline period to confirm insomnia. They will also be scheduled for either in-lab or at-home PSG at this time.
Randomization will be performed with a centralized computerized application, Treatment Assignment Tool - University of Michigan (TATUM), with random block sizes of up to 10, and stratified based on participant gender, age (≤40 or >40 years old), and presence vs. absence of a substance use disorder. Randomization is performed by an unblinded study team member entering necessary data for stratification into the system, which will then return a treatment assignment. Allocation to treatment condition by the study team member is conducted only after all study eligibility criteria have been met. Randomization will allocate participants in a 1:1 ratio to 6 sessions of either CBT-TM or SHE-TM. Before each session, the therapist will contact participants to confirm their upcoming appointment and to provide a slide deck of topics to be covered; following each session, the therapist will send any resources or follow-up relevant to the recently completed session.
Follow up assessment begins immediately after the completion of treatment when participants complete post-treatment assessments, one additional night of PSG, and one week of sleep diary/actigraphy. At 3-, 6-, and 12-months post-treatment, participants will again complete self-report assessments and one week of sleep diary/actigraphy.
Once enrolled, we will utilize a variety of retention strategies that have been successful in our previous studies. These strategies include: (1) requesting participants to designate at least two contact persons to assist in locating them as needed; (2) providing participants with multiple reminder phone calls before appointments; (3) sending follow-up letters by mail to maintain participant engagement; (4) encouraging continuity of contact with individuals on the research team (participants will be remunerated with $5 at each follow-up time point for contacting the research team to schedule follow-up assessments and update contact information); and (5) an analytic approach that minimizes the impact of missing data on estimation of outcomes.
Throughout participation, any adverse events (AEs), both solicited and spontaneously reported, will be reported to the Principal Investigator, who has ultimate responsibility to determine severity and relatedness of any events. Events will then be reported to IRBMED and NIH, following reporting guidelines based on severity and relatedness of AEs.
Subjects and research staff assessing outcomes will be blind to treatment condition to help ensure a rigorous and unbiased approach. PSG records are similarly analyzed agnostic to treatment condition. Therapists will not be blind to CBT-TM vs. SHE-TM, but we will use rigorous treatment fidelity procedures (see below) to minimize the risk of bias in our findings. Data will be coded to maintain the blind for treatment sessions.
Table 3: Timing of Assessments and Interventions Throughout Study Enrollment
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Pre-Randomization
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Intervention (6 sessions)
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Post4
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3m FU4
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6m FU4
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12m FU4
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|
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SCRN1
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BSL2
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Wk3
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Wk4
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Wk5
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Wk6
|
Wk7
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Wk8
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Wk9
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Wk20
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Wk32
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Wk60
|
|
|
V1
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V2
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V33
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S1
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S2
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S3
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S4
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S5
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S6
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V43
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V5
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V6
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V7
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|
Consent
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X
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|
|
|
|
|
|
|
|
|
|
|
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Psychiatric Screening
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X
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|
|
|
|
|
|
|
|
|
|
|
|
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Demographics
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X
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|
|
|
|
|
|
|
|
|
|
|
|
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AUDIT
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X
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|
|
|
|
|
|
|
|
|
|
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X
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Structured psychiatric interview
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|
X
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|
|
|
|
|
|
|
|
|
|
|
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Structured sleep Interview
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|
X
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|
|
|
|
|
|
|
|
|
|
|
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PSG
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|
|
X
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|
|
|
|
|
|
X
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|
|
|
|
Actigraphy
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|
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X
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|
|
|
|
|
|
X
|
X
|
X
|
X
|
|
Sleep Diary
|
|
|
X
|
X
|
X
|
X
|
X
|
X
|
X
|
X
|
X
|
X
|
X
|
|
ISI
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X
|
|
X
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|
|
|
|
|
|
X
|
X
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X
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X
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MEQ
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|
|
X
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|
|
|
|
|
|
X
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|
|
|
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ESS
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|
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X
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|
|
|
|
|
|
X
|
X
|
X
|
X
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DBAS
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|
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X
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|
|
|
|
|
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X
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|
|
|
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MFI-20
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|
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X
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|
|
|
|
|
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X
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X
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X
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X
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GAD-7
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|
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X
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|
|
|
|
|
|
X
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X
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X
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X
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PHQ-8
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|
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X
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|
|
|
|
|
|
X
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X
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X
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X
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SF-12
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|
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X
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|
|
|
|
|
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X
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X
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X
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X
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SIP-R
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|
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X
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|
|
|
|
|
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X
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X
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X
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X
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PACS
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|
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X
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|
|
|
|
|
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X
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X
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X
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X
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TLFB
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|
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X
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|
|
|
|
|
|
X
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X
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X
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X
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CBT-TM or SHE-TM
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|
|
|
X
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X
|
X
|
X
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X
|
X
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|
|
|
|
|
TEQ
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|
|
|
X
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|
|
|
|
|
X
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|
|
|
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WAI
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|
|
|
X
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|
X
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|
|
|
X
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|
|
|
|
Comprehension
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|
|
|
X
|
|
|
|
|
|
X
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|
|
|
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1- At screening, ISI and AUDIT eligibility will be confirmed via chart review or online questionnaire. Demographics and psychiatric screening will come from a combination of chart review and prospective participant questionnaire. 2- Baseline assessments will be collected as a mixture of in-person and remote interactions. 3- V3 represents the period between V2 and S1. V3 and v4 will last approximately 7-14 days, during which time participants will undergo PSG and maintain sleep diary/actigraphy. Participants will complete baseline assessments via REDCap only after passing baseline PSG. 4- All post-intervention visits are determined relative to treatment completion date.
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Interventions
Participants will be randomized to complete 6 sessions of telemedicine-delivered Cognitive Behavioral Therapy for Insomnia (CBT-TM) or Sleep Hygiene Education (SHE-TM). Both interventions will be delivered remotely by a Master’s-level therapist familiar with time-limited and evidence-based therapies who has been trained on the study interventions by a study investigator with a Diplomate in Behavioral Sleep Medicine (DAC). Prior to delivering therapy, the therapist will demonstrate understanding of the material by successfully completing a written examination. Both interventions are designed to be delivered over 6 consecutive weeks and each session lasts between 30 and 60 minutes, with different topics covered each week, as outlined in Table 4.
Table 4: Session-by-Session Breakdown of Study Interventions
Telemedicine-delivered Cognitive Behavioral Therapy for Insomnia (CBT-TM)
Session 1
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45-60 min
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CBT-TM Introduction/Sleep Hygiene - orientation to insomnia and CBT. Identify and alter daytime behaviors, substances, and environmental conditions that can disrupt sleep
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Session 2
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45-60 min
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Sleep Scheduling Strategies (Sleep Restriction/Stimulus Control) - improves sleep quality, duration, and timing with behavioral strategies that increase the drive for sleep and stabilize the circadian timing system.
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Session 3
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60 min
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Counter-Arousal Strategies – reduces physiological and cognitive arousal through constructive worry and relaxation. Time in bed adjustments will be made according to an algorithm that combines sleep diary information with patient-reported side effects during the day
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Session 4
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30-45 min
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Cognitive Therapy - aims to identify and alter dysfunctional beliefs about sleep and functioning that contribute to maintaining insomnia. Time in bed adjustments continue.
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Session 5
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30-45 min
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Session 6
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45-60 min
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Relapse Prevention for Insomnia – reviews treatment gains, emphasizing the behaviors and adaptive cognitions necessary for maintaining these gains. Relapse prevention of insomnia involves identifying high-risk situations, promoting realistic appraisals about future insomnia episodes, and providing behavioral and cognitive strategies for dealing with the inevitable occasional poor night of sleep.(59)
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Telemedicine-delivered Sleep Hygiene Education (SHE-TM)
Session 1
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45-60 min
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Insomnia History - reviews the participant’s insomnia history, including triggers that initiated the sleep problem, its duration, severity, and frequency, premorbid sleep characteristics, and previous sleep medication and non-medication treatments.
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Session 2
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45-60 min
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Sleep Education - provides basic education about why we sleep, sleep stages, how sleep is regulated at night, and sleep changes across the lifespan
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Session 3
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45-60 min
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Substance Use and Sleep - focuses on the effects of alcohol and other licit and illicit substances on sleep
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Session 4
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30-45 min
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Environmental Factors and Sleep - focuses on the importance of creating a sleep-conducive environment for optimizing sleep quality
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Session 5
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30-45 min
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Lifestyle factors affecting Sleep - addresses the effects of diet, exercise, and napping on sleep. Subjects will also be educated about the importance of regularity of activity and meal times to enhance sleep quality
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Session 6
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45-60 min
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Sleep Maintenance Strategies –reviews treatment gains and emphasizes the principles covered over the previous five sessions in order to maintain sleep improvements
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Treatment Monitoring and Therapist Fidelity
Participant treatment fidelity will be assessed by tracking session attendance and reschedules/cancellations. Additionally, participants will be given a content comprehension measure following the first therapy session and at the final treatment visit.
A random sample of 25% of treatment session videos will be reviewed by the study therapist supervisor (DAC). Each of these videos will be scored according to a Treatment Fidelity and Therapist Competence measure designed for this study, which include monitoring to ensure that critical session topics are covered and that the therapist demonstrates competence in basic therapy skills. In addition, the therapist will be assessed by the participant’s completion of the Working Alliance Inventory and Therapist Evaluation Questionnaire.
Participant adherence with treatment protocols will be monitored by the study therapists via daily sleep diaries. Treatment will be modified or discontinued if adverse events are reported. During the trial, any necessary treatment for co-occurring medical, mental health, or alcohol/substance use disorder conditions is permitted.
Data Management and Analysis
Data Collection and Management
The Project Coordinator and Data Manager will directly oversee the day-to-day data collection and quality assurance activities. On a monthly basis they will review data for accuracy and out-of-range values. Built-in and study-specific data validation rules in our study database will be used to facilitate these checks. Routine data backups will be part of this process. Collection of identifiable data from participants will be kept to the minimum necessary to carry out study procedures; this data will be kept in a secured, password-protected database.
De-identified trial data will be uploaded into the NIAAA Data Archive (NIAAADA) biannually, making it accessible to other researchers interested in the treatment of Sleep Disorders and/or Alcohol Use Disorder. Trial results will be communicated via presentations at national scientific meetings, publication in peer-reviewed journals, and dissemination of aggregate data to local clinics.
Statistical Considerations
We will utilize an “intent-to-treat” (ITT) approach, meaning that all randomized subjects will be included in analyses, regardless of whether they complete all assessments, and all hypothesis testing will use two-sided tests (p-values <0.05 will be considered significant). Analyses will begin with descriptive examinations of distributions of key variables collapsed by categories, if necessary, and to review data for outliers and clear anomalies. Tests for linearity, independence, missingness, and distributional assumptions will be performed. Normalizing transformations will be utilized, if necessary. Prior to fitting any analytic models, a graphical exploration of the outcome variables will be conducted. Primary analyses will focus on the overall sample. We will validate randomization by testing for covariate balance between groups. If differences are observed, we will adjust for these variables or conduct stratified analyses.
To minimize missing data, we will make every effort to gather follow-up information from all participants using strategies that have proved successful in our prior research. Where we have missing variables that are necessary for analysis, we will perform multiple imputation of missing data and combine the results from 5 imputations based on Rubin’s method to produce an estimate and the corresponding confidence interval accounting for missing data uncertainty. It is important to note that the proposed mixed-effects regression modeling will allow for the use of data from all participants and provide unbiased parameter estimates that account for missing data under the missing-at-random assumption. We will also examine for non-random attrition, and if we find, for example, attrition rates to depend on a baseline covariate, we will include this covariate in the modeling.
Bivariate associations between independent variables (including treatment group) and primary outcomes will be examined prior to model building. For example, we will examine correlations and compare groups using appropriate comparison methods such as t-tests, F-tests, and bivariate generalized linear models with specification of the appropriate link function based on the distribution of the given outcome, or their non-parametric counterparts (e.g. Mann-Whitney). To compare intervention conditions, we will also compare average pre-post differences on the outcomes of interest.
Generalized linear mixed models (GLMMs) will be the focal models used to examine treatment effects and changes in the primary outcome measures of interest. We chose GLMMs because: (1) GLMMs take into account correlations between data points (e.g. repeated measurements on individuals), and (2) GLMMs allow for the retention of all participants in the analysis, including those with incomplete data. Primary outcome variables include those with Gaussian distributions (e.g., insomnia severity), as well as those with count processes (e.g., percent days abstinent) that likely follow a Poisson distribution. Nonetheless, such assumptions will be scrutinized and, as needed, modifications (e.g. zero-inflation) and alternative families of distributions (e.g. negative binomial) will be considered. An autoregressive covariance specification will be used first for GLMMs, but appropriateness of other covariance specification will also be considered.
Primary Outcome Analyses
Specific Aim 1: Between Group Treatment Effects on Insomnia and Daytime Symptoms
We will assess treatment effects on insomnia and daytime symptom outcomes at post-treatment and at 3-, 6-, and 12-month follow-up via bivariate analyses described above, comparing the CBT-TM to SHE-TM. We will then estimate treatment effects on insomnia and fatigue using a GLMM approach. An indicator variable for the CBT-TM group will be used to generate estimates in relation to SHE-TM. If preliminary analyses suggest that the effect of the intervention may vary over time, we will model an interaction of intervention by time. In addition to the treatment group indicator, GLMMs will include the baseline values of the response variable as an independent variable.
- Primary outcomes: Post-treatment ISI total score and MFI General Fatigue subscale score
- Exploratory outcomes: Other measures of insomnia and daytime symptoms as captured by self-report measures, sleep diary, and actigraphy measures across time points
Specific Aim 2: Between Group Efficacy for Alcohol Relapse
We expect that the primary drinking outcome (percent days abstinent) will likely follow a Poisson distribution, so GLMM models will be specified accordingly (e.g., with specification of the log link function). Nonetheless, as described above, assumptions will be scrutinized and adjusted, if necessary. Analyses will then proceed as described above for Aim 1 assessing treatment effects on drinking outcomes.
- Primary outcome: percent days abstinent as measured by TLFB at post-treatment
- Exploratory outcomes: Other indices of drinking-related behavior including percentage of heavy drinking days and drinks/drinking day, etc. as measured by TLFB across time points
Specific Aim 3: Treatment Effects on Homeostatic Sleep Drive
The analytic procedures for Aim 3 will be similar to those described by Krystal and Edinger (46). We will compare changes between baseline and post-treatment SWA outcomes for the CBT-TM and SHE-TM groups. The primary outcome will be post-treatment dissipation of SWA in NREM sleep (i.e., best-fit slope of delta power, where the slope is the exponent of best-fit exponential function). To assess for differences in change of slopes between the conditions, we will use analysis of variance (ANOVA) modeling. We chose ANOVA modeling to be consistent with the prior work and because GLMMs offer little advantage over ANOVAs with only two time points. Similar modeling procedures will be used to assess differences for secondary Aim 3 outcomes (e.g., baseline-to-post-treatment change in SWA power in the first NREM period averaged over the entire night) assessed during PSG.
Sample Size and Detectable Effect Size
Target sample size for this study is 150 participants, with allocation of 75 participants to each treatment group. Power analyses were conducted using G*Power 3.1.9 software, and assumed a two-sided test with α=.05. Because of the lack of commercially available software for calculating power for GLMMs, we have conservatively estimated power for traditional regression approaches for the specific aims without accounting for GLMM methods that will allow for inclusion of participants with partial follow-up data or for the gains in power generated by the use of repeated measures. Power was based on a conservative estimate of n=120 individuals (n=60 in CBT-TM; n=60 in SHE-TM), which represents an 80% follow up rate of the initial sample of n=150, and does not take into account multiple imputation and other strategies for handling missing data.
Based on this conservative approach, we are powered for conducting bivariate comparisons, pre-post testing of intervention effects, and comparing intervention groups and we show the viability of our sample size for detecting realistic effect sizes in the proposed GLMM models. For comparisons between the treatment group (n=60) and the control group (n=60), we have >80% power to detect a Cohen’s d > 0.51 (e.g., differences between groups at a single follow-up), which represents a medium effect size. This effect size, as well as the proposed sample size, is similar to prior published studies of interventions targeting a comorbid condition to reduce alcohol use (e.g., pain or depression interventions aimed at reducing drinking (60, 61)). Consequently, we will have more than adequate power to detect meaningful effect sizes that we expect based on our prior studies of CBT and the extant literature.