Twenty percent of US adults report chronic pain symptoms. Both psychological symptoms and sleep issues commonly co-occur with chronic pain. Chronic pain is a frequently reported symptoms of Chiari Malformation (CM); however, the cause of pain symptoms is not fully understood, and pain is not associated with the extent of neural abnormality in CM.

ACT is not a set of techniques, but rather a way of thinking. ACT encourages acceptance, as opposed to avoidance of unwanted feelings, all in the context of mindfulness (i.e., being aware of one's present environment and in tune with internal thoughts and emotions). ACT has been found to be successful at reducing pain perceptions and targeting multiple symptoms at one time. However, ACT has not been examined in CM and it is unknown whether ACT will improve sleep as well as pain-related symptoms. The purpose of the current study is to assess the efficacy of an online ACT intervention at reducing pain interference and sleep dysfunction symptoms in a sample with CM. It is hypothesized that CM patients may benefit from Acceptance and Commitment Therapy (ACT). More specifically it is hypothesized that the treatment group will report significantly less pain interference and psychological flexibility compared to the control group. It is also hypothesize that ACT will mediate the relationship between sleep dysfunction and pain interference.

Based on power analyses the sample size will be 56. The sample will be recruited online and randomized to the treatment or control group. The intervention will consist of eight modules that are administered weekly over eight weeks. Additionally, a 7-day sleep diary will be administered the week prior to the intervention and the week after the intervention. Follow up assessments will be administered upon completion of the 8-week intervention (at the beginning of week 9), 1-month after, and 3 months after the completion of the intervention.

Chronic pain is extremely prevalent with 20% of adults in the US reporting symptoms (Dahlhamer, 2018). Further, when accounting for lost productivity and direct health care costs, the financial burden of chronic pain has been estimated to be $560-$630 billion annually (Gaskin & Richard, 2011). A myriad of factors contribute to chronic pain including psychological symptoms and sleep. Though psychological symptoms often co-occur with chronic pain with rates estimated to be as high as 50% (Kroenke et al., 2011), chronic pain co-occurs at an even higher rate with sleep dysfunction (89%) (van Hecke, Torrance, & Smith, 2013). Sleep is believed to have a reciprocal relationship with pain, such that pain impacts sleep and sleep impacts future pain (M. T. Smith, Huang, & Manber, 2005) reciprocal relationship makes sleep an essential aspect of chronic pain that warrants attention in interventions. One intervention that has shown particular promise in treating chronic pain is Acceptance and Commitment Therapy (ACT).

ACT is not a set of techniques, but rather an orientation. This orientation focuses on living a fulfilling life by way of living in line with one's values. In addition to living a life based on values, ACT encourages acceptance, as opposed to avoidance of unwanted feelings, all in the context of mindfulness (i.e., being aware of one's present environment and in tune with internal thoughts and emotions) (S. C. Hayes, Luoma, Bond, Masuda, & Lillis, 2006). Since the focus is on an orientation rather than specific techniques, ACT can be used as a transdiagnostic intervention, targeting multiple symptoms at one time. As previously noted, chronic pain is a complex diagnosis, with many interacting factors including psychological symptoms, sleep, and decreased daily functioning. ACT effectively treats the complex presentation of chronic pain. Chronic pain already costs society billions of dollars annually and administering psychological interventions are expensive and may not be available to all those in need. Online ACT interventions remedy this issue by providing services to those where treatment may not be readily available for a fraction of the price.

Though a handful of studies have explored different online ACT interventions, and found them to be efficacious, however, they have been unable to flexibly address individual differences in symptom presentations as they present the same information regardless of the participant's symptoms (Buhrman et al., 2013; S. Hayes et al., 2014; Kristjánsdóttir et al., 2013; Lin, Klatt, McCracken, & Baumeister, 2018; Simister et al., 2018; Trompetter, Bohlmeijer, Veehof, & Schreurs, 2015). Additionally, all prior online ACT interventions for chronic pain focused on pain primarily, providing examples and metaphors around the experience of pain. The aim is to administer an intervention that broadly teaches ACT philosophies without focusing only on pain, addressing individual differences in symptom presentation and allowing for personalization. The goal is to address chronic pain but to also facilitate the generalization of skills to comorbid conditions that often perpetuate the experience of chronic pain (i.e., depression, anxiety, and sleep dysfunction). Efficacy will be assessed through reductions in pain interference as well as comorbid conditions (i.e., sleep dysfunction, anxiety and depression).

Chronic pain is a commonly reported symptom of Chiari Malformation (CM). This under-researched diagnosis is characterized by the cerebellar tonsils descending 5mm or more into the spinal canal and impacts approximately 3.25 million people or 1% of the US population (B. W. Smith et al., 2013). Although chronic pain is commonly reported in CM, the etiology of a symptomatic presentation is not fully understood, and there is no direct relationship between the extent of descension of the cerebellar tonsils and pain. Regardless of elucidating the etiology of pain in CM, those with this complex chronic pain diagnosis would likely benefit from psychological and behavioral based interventions. Further, no ACT based intervention has been administered to a sample with Chiari Malformation. The purpose of the current study is to assess the efficacy of an online broad ACT intervention on a sample with Chiari Malformation.

Aim 1: Determine the efficacy and breadth of an online ACT intervention in decreasing pain interference, sleep dysfunction, depression, and anxiety.

Hypothesis 1: The treatment group will report significantly less pain interference, sleep dysfunction, depression, and anxiety compared to the control group.

Aim 2: Assess psychological flexibility as a mechanism of ACT. Hypothesis 2: Psychological flexibility will mediate the trajectories in pain interference, sleep dysfunction, depression, and anxiety over time.

The following is a summary of the protocol:

(Part 1): (Both Treatment & Waitlist Control Groups) Consent will be established via an online form. Once consent is acquired a set of questionnaires covering demographics, as well as quality of life, pain interference, pain acceptance, anxiety, depression, stress, and sleep; taking approximately 30 - 45 minutes will be completed. Internet access is required to complete these questionnaires on a computer, tablet, or mobile phone.

(Part 2): (Both Treatment & Waitlist Control Groups) Next, a 7-day sleep diary will be completed. A Qualtrics link will be emailed out each morning (the email will be sent out by midnight the night prior) that will lead to a 2-5 minute survey (11 questions). This survey is to be completed as close to waking as possible to obtain the most accurate information. Once the final day of the sleep diary is completed, randomization into the treatment or control group will occur. The treatment will begin the following Friday after the completion of the sleep diary.

(Part 3): (Treatment Group alone) Once a week, for the next 8 weeks, a short battery of questionnaires, followed by the online intervention (taking a combined total of approximately 30-45 minutes a week) will be completed. The Qualtrics link will be sent via email every Friday morning. If the assessment and intervention has not been completed by the end of day 4 (Monday), a phone call will serve as a reminder and to answer any technical or unresolved issues. Each online intervention ends with a practice assignment for the remainder of the week. The treatment group will receive a weekly call from a Master's-level clinical student; the time of this call will be set up online during the first session in Part 3. During the call will serve to help troubleshoot any technical difficulties, as well as clarify any questions about the material being taught in the intervention.

(Waitlist Control Group) Each week for the next 8 weeks a short battery of questionnaires taking approximately 10-15 minutes will be completed. Technical issues will be remedied through communication with the the study email (chiaristudy@gmail.com).

(Part 4): (Both Treatment & Waitlist Control Groups) At the beginning of the 9th week, an immediate follow-up set questionnaires (same as in Part 1) will be administered.

(Part 5): (Both Treatment & Waitlist Control Groups) Next, a 7-day sleep diary will again be completed, taking approximately the 2-5 minutes (11 questions), and completed as close to waking as possible to provide the most accurate information.

(Part 6) (Both Treatment & Waitlist Control Groups) 1-month after completing the intervention the same battery as in Part 1 and Part 4 taking about 30 - 45 minutes will be completed.

(Waitlist control group) Upon completion of the 1-month follow-up assessment, the waitlist control group will be offered the opportunity to take part in the online intervention.

(Part 7) (Treatment Group only) 3-months after completing the intervention, a final Qualtrics link to complete the same battery as in Part 1, 4, and 6 taking about 30 - 45 minutes.

Inclusion Criteria:

• Fluent in English
• Chiari Malformation
• Access to the internet
• Be willing to commit approximately an hour a week for 8 weeks to engage in the intervention and homework
• Experience persistent pain for a minimum of 3-months
• Rate their pain intensity as greater than a 3 on a scale from 1-10
• Be stable on psychotropic medication for the past 3 months (if taking psychotropic medication)

Exclusion Criteria:

• Blindness
• Currently receiving Acceptance or Commitment Therapy or Cognitive Behavioral Therapy
• Have active suicidal ideations
• Diagnosed with a severe psychiatric disorder including bipolar disorder and schizophrenia