Description

Background

The burden of cognitive impairment is severe, and often hinders affected people to act independently in daily life, and their families frequently carry a large burden. A great challenge is to support the maintenance of cognitive health in order to avoid cognitive disability. Individuals diagnosed with subjective cognitive decline (SCD [unimpaired performance on cognitive tests]), mild cognitive impairment (MCI [Impaired performance on cognitive tests]) are frequently affected by health issues (such as stress symptoms, anxiety, and depression), as well as social avoidance due to the unclear prognosis of their cognitive dysfunction. Thus, the need for efficient psycho-social support are utterly needed both from an individual- as well as a societal perspective.

The investigators have developed a novel psychological treatment manual focused on supporting individuals with SCD and MCI. The treatment manual is centered on facilitating behavioral change in accordance with personal values and long-term goals even in the presence of negative experiences, as well as to promote meaningful life-style changes. The treatment manual has its basis in the cognitive behavioral therapy (CBT) tradition, but the investigators have strived to adapt the manual to suit a cognitively affected population with for example with reminders, more sessions, validation techniques, repetition, and concrete examples etc. Recent developments within CBT, particularly acceptance commitment therapy (ACT), emphasize the utility of acceptance and mindfulness strategies, contrasting interventions focused on reduction or control of symptoms. In brief, the treatment objective in ACT and in our study is to improve functioning by increasing psychological flexibility. Psychological flexibility is defined as the ability to notice and accept interfering thoughts, emotions and bodily sensations without acting on them, to facilitate behaving in accordance with personal values and long-term goals also in the presence of those negative experiences.

The specific research questions are:

• Can the psychological treatment rationale with its focus on psychoeducation, validation, exposure, and acceptance among other therapeutic techniques, preserve cognitive status, increase life satisfaction, improve psychological health, show positive biological changes in individuals with SCD/MCI?
• Are potential treatment effects maintained longitudinally?
• Can significant treatment predictors be identified on treatment outcome?
• How does the participants perceive the treatment?

Hypotheses Main hypothesis

1. The main hypothesis declares that participants obtaining PIPCI will increase their psychological flexibility (AAQ2) compared to participants in the control groups and that this effect will be retained at 6 months follow-up.

Secondary hypotheses

1. The secondary hypotheses declares that participants obtaining PIPCI will improve psychological health (stress measures, quality of life, depression and general health), in correspondence with biomarker changes compared to the control groups
2. An additional secondary hypothesis declares that participants obtaining PIPCI, and participants in the active control group, will improve on the cognitive test measures compared to the waiting list group. However, we do not have any directed hypothesis comparing PIPCI and the active control group.

Exploratory research questions (without any directed hypotheses)

1. Can we identify significant pre-intervention predictors for intervention outcomes?
2. How do participants perceive the intervention?

Methods

Patients will be recruited from the Cognitive Centers at the Karolinska University Hospital, Solna, and Huddinge within Stockholm metropolitan area, where they partake in cognitive examination (i.e., neuropsychological assessments, anamnesis, biological markers etc.). These patients will be younger than 70 years and will have received a diagnosis of SCD or MCI.

Randomization

The identified patients receive verbal and written information about the project. In the next step, patients that express interest for the project signs an informed consent and will then be evaluated in a semi-structured interview, conducted by a psychologist at the Unit of Behavioral Medicine at Karolinska University Hospital, Stockholm, Sweden. Patients that fulfill the inclusion criteria and considered suitable for treatment, are randomized. For the randomization process, the investigators will engage the Karolinska Trial Alliance, Stockholm, Sweden (https://karolinskatrialalliance.se/en/), that is a professional clinical research center at Karolinska University Hospital.

RCT design and groups

One group will receive psychological treatment (experimental group), one group will get cognitive training (active control group), and one group will get the gold standard treatment, which is health information (TAU). After the finalization of the post-intervention evaluations, the TAU group will be randomized to participate in one of the active interventions. Participants need to be present for at least 75 % of the intervention and completed at least 75 % of the homework to be considered adherent. All evaluation assessments will be conducted by blinded assessors. Participants cannot be blinded to their group assignment, which is typical of non-pharmacological intervention trials.

Power calculation

Sample size was calculated with the R package SIMR, which allows power calculations of Linear Mixed Models (LMM). The sample size estimate is based on changes in our primary outcome, AAQ2. The model included the interaction of time (pre- versus post-test 1; continuous) and group (experimental versus active control; factor). The model also had subject ID (factor) as a random effect to account for repeated measurements. The analysis showed that to get a significant difference between the experimental group and the active control group we need at least 40 participants (to have 93% power) in each group. We expect a 15% attrition rate, so an initial recruitment of 120 participants should ensure that about 105 participants remain in the final sample.

Ethical considerations

The project has an approved ethical application (Dnr. 2022-06139-01) by the Regional Ethical Committee in Stockholm and follows the Declaration of Helsinki. Cognitive impairments are often related to progressive decline in cognitive and intellectual abilities. Thus, there is a risk that patients may progress in their decline during the period in which they are included. The investigators therefore need to be watchful on potential progression, and referral to other health care units can be needed if the patient's conditions are changing to the worse. The treatment/rehabilitation might in some cases be perceived as psychologically tough when it comes to behavioral changes. This is not unique for the current study, but often a part of any psychological clinical treatment/rehabilitation. To provide qualified support to the patients, only professional clinicians will interact with the participants. Most of them will be licensed and sanctioned by the Social Board of Health and Welfare (Socialstyrelsen) who is governed by ethical guidelines and the need to protect the patients and their personal information.

Statistical analysis

The continuous longitudinal data derived from the RCT will be analyzed using appropriate growth models (e.g., LMM) that in addition to studying change at the group level also can: model change on the individual level; flexibly incorporate time-varying predictors; handle dependency for repeated observations and provide correct estimates with missing data under largely unconstrained missing data conditions. As a default strategy we will use LMM to analyze the condition by time interaction and will follow established recommendations for model specification and reporting results. In the main analysis, we will compare intervention change between the PIPCI group and the active control group. However, we will also compare the PIPCI group and the active control group with the waiting list group. An alpha level of 0.05 and a 95% CI will be used to evaluate the main and secondary analyses.

In addition to using the growth model framework to investigate predictors of intervention outcomes, we will also apply non-linear models using machine learning methodology, such as support vector machines (SVMs). The SVM fits the separating hyperplane with support from the cases that lie closest to each other in hyperspace but which are of different labels, the support vectors. The developed risk models will mainly predict cognitive test measures (neuropsychological assessments), and biological markers (visual ratings derived from magnetic resonance imaging, and cerebrospinal fluid dementia measures.

The qualitative approach will be conducted in line with consolidated criteria for reporting qualitative research (COREQ), with the aim to examine in-depth participant's experiences of participation in the RCT. Interviews will be conducted with participants in the study after the long-term follow-up. Interviews will be digitally recorded and transcribed, and content analysis will be used in the analysis.