Remote tDCS and Chair Yoga for Chronic Knee Pain in Alzheimer's Patients

The PROMIS Pain Interference 4a measures pain's impact on daily activities, with four items rated on a 5-point scale. Patients will self report this data based on their activities from the last 7 days. This tool has high reliability with a Cronbach's alpha ~0.90.

The MOBID-2 asks caregivers to evaluates the pain of participants during specific activities(guiding hands together, turning in bed, sitting at bedside, etc.) and at specific parts of the body (head, mouth, neck, heat lungs, chest wall, etc), with a score range of 0-10; scores over 2 are clinically significant. The MOBID-2 shows high reliability with a Cronbach's alpha 0.86-0.89.

The ActiGraph wGT3X-BT and ActiLife software objectively measures sleep disturbance. Wrist actigraphy is a valid and reliable tool for assessing sleep in patients with ADRD. Patients will be asked to wear the watch on their nondominant wrist, with caregiver assistance. Actigraphy data are analyzed to calculate sleep outcomes, including total sleep time, wake time, and daytime naps, using the standard algorithm in ActiLife software without additional hand scoring.

MoCA is a 30-point test that includes 12 subtasks that cover a total of 8 cognitive domains (e.g., memory, orientation, attention/concentration, executive function), with scores ranging 0-30, with higher scores indicating better global cognitive performance. The MoCA features educational correction by the addition of 1 point for the patient with less than a 12th-grade education. The MoCA has high internal reliability (Cronbach α = .83), high test-retest reliability (ICC = 0.92), high interrater reliability (ICC = .81), and high content validity (r = .87).

Pain related cortical responses will be measuring using a continuous multichannel fNIRS imaging system (LIGHTNIRS, Shimadzu, Kyoto, Japan). This instrument encompasses 8 light sources (each emitting laser light at 780, 805, and 830 nm) and 8 detectors connected to comfortable headgear using optical fibers. Optical recordings will be collected during thermal pain stimulation and punctate pain stimulation.

The Bittium Faros™ 180 device will be used to record continuous electrocardiogram (ECG) data for analyses of cardiac rhythms. The device samples ECG at 1000 Hz and is attached using three self-adhesive electrodes on the torso. Respiratory Sinus Arrhythmia (RSF) and Heart Rate (HR) will be measuring over 3 minutes during 3 postures (stand-sit-stand) for a total collection period of 9 minutes.

The NPI will be administered to the caregiver to evaluate the participant's neuropsychiatric symptomatology of dementia. The NPI uses a 4-point Likert-type scale for frequency and a 3-point Likert-type scale for severity of 12 sub-domains of dementia (e.g., delusions, hallucinations, agitation/aggression, night-time behavioral disturbances, and appetite and eating abnormalities). These are summed to yield an overall score of 0-144 (each item rated frequency X severity, totaling 0-12), with higher scores indicating greater symptoms. Internal consistency reliability of the NPI is high with a Cronbach's alpha = 0.80.

TUG will measure functional mobility by timing patients as they stand from a chair, walk 10 feet, turn 180 degrees, return, and sit down. The average of three tests will be recorded in seconds. TUG is a simple and widely used tool for assessing lower limb function, mobility, and fall risk, with high inter-rater (ICC = .99) and intra-rater reliability (ICC = .99).

Cognivue Clarity is the first FDA-cleared computerized cognitive assessment device to evaluate a range of specific cognitive domains (e.g., motor speed, visuospatial abilities, verbal and visual episodic memory, attention, executive function, reaction time). It is an easy-to-use automated platform for evaluating and tracking cognitive impairment, with 10 separately scored subtests (2 for visuospatial functioning, 4 for perceptual processing, and 4 for memory). The 10-minute assessment provides a numerical score categorizing performance as normal, mild impairment, or moderate impairment. Classification ranges are no cognitive impairment (CI) (≥75), low-mild CI (51-74), and moderate-severe CI (≤50).

We will measure participant satisfaction with treatment using the CSQ-8. The CSQ-8 comprises eight items that are summed to yield an overall score of 8-32, with higher scores indicating greater satisfaction. The CSQ-8 has a reported Cronbach's alpha coefficient of 0.87-0.93. We will evaluate the presence and severity of possible side effects of treatment at the end of each session on a 0 (not at all) to 10 (highest degree) scale. Participants will be asked in an open-ended manner whether they experienced any side effects, and they will complete a brief questionnaire assessing side effects that can occur with tDCS or/and OCY (e.g., itching, headache, fatigue, dizziness).

To measure acceptability, we will administer an adapted questionnaire to patients and caregivers at the end of the intervention. Items rated from 0 (strongly disagree) to 10 (strongly agree) will include (a) ease of preparing tDCS and chair yoga props, (b) complexity and usability of the tDCS device, (c) ease of following yoga poses, (d) helpfulness of video conferences, (e) confidence in using tDCS, and (f) overall benefit of the interventions. Negative items will be reverse coded, and total scores will range from 0 to 100, with higher scores indicating greater acceptability.

The QDRS is a brief, informant-based tool designed to assess cognitive function and detect dementia quickly, typically in 3-5 minutes. It evaluates 10 domains, including memory, orientation, decision-making, and daily activities, with scores ranging from 0 to 30, where higher scores indicate greater impairment.

• 0-1.5: No dementia
• 2.0-5.5: Mild cognitive impairment (MCI)
• 6.0-12.5: Mild dementia
• 13.0-20.5: Moderate dementia
• 21-30: Severe dementia

Descending pain modulation will be assessed by measuring the change in pressure pain threshold on the trapezius immediately after immersing the contralateral hand up to the wrist in a 12 °C cold-water bath for one minute. An increase in pressure pain threshold following immersion indicates stronger descending pain modulation, with higher CPM scores reflecting better modulation.

Quality of Life will be assessed using the 13-item QOL-AD, which evaluates physical health, mood, memory, and overall life satisfaction. Each item is rated from 1 (poor) to 4 (excellent), with total scores ranging from 13 to 52; higher scores indicate better QOL. The QOL-AD has high Internal consistency (Cronbach α = 0.80 to 0.89) and strong validity, correlating well with other QOL measures, cognitive function, and mood assessments.

Mini-MoCA: The 5-minute Mini-MoCA is a shortened version of the MoCA, targeting tasks most sensitive to mild cognitive impairment. It takes approximately 5 minutes to administer and assesses five cognitive domains: attention, verbal learning and memory, executive function/language, and orientation. The cut-off score is 12, with 1 point added for persons with less than 12 years of education.