Effectiveness of the Nordic Sensi Chair in the Treatment of Dementia Behavioral Disorders (NSC-DEMEN)

Objective The main objective of this study is to evaluate the effectiveness of the Nordic Sensi® Chair in the management of behavioral symptoms of dementia (BPSD) in real clinical practice in people with dementia (PwD) admitted to nursing homes. The secondary objective of the present study was to assess the benefits of the NSC on cognitive functioning and quality of life of patients as well as its benefits on the performance of the daily work activities of care staff.

Background Dementia is a neurodegenerative syndrome characterised by a progressive impairment of the cognitive and functional abilities that causes a huge social and human fracture. The number of people with dementia increases globally and according to population projections, if the current prevalence of dementia remains constant the number of people with dementia will rise to 82 million in 2030 and almost double in 2050.

In addition to the cognitive and functional deficits, behavioural and psychological symptoms of dementia (BPSD) are one of the most important challenges that both people with dementia (PwD) and their caregivers face throughout the course of the disease. BPSD consist of a heterogeneous group of symptoms such as depression, anxiety, delusions, hallucinations, irritability, disinhibition, agitation, aberrant motor behaviour, apathy or sleep and eating problems. BPSD results in decreased patient well-being, impaired quality of life, excess morbidity and hospital admission and cause a heavy burden on caregivers, often leading caregivers to make the decision to institutionalise. In nursing-homes BPSD can place a greater care staff stress and other residents.

BPSD management includes both pharmacological and nonpharmacological therapies. Medication is often used and many patients with late-stage dementia are treated with psychoactive drugs, although in many cases achieve only modest benefits in controlling symptoms while exposing patients to the risk of possible adverse events. On the contrary, nonpharmacological interventions are considered to have fewer undesirable effects making them safer options. Therefore, currently there is a consensus to consider nonpharmacological therapies as the first line treatment of BPSD with the exception of emergency situations or when symptoms have not responded effectively to non-pharmacological interventions.

There is a wide range of nonpharmacological approaches that have shown positive results for the management of BPSD from sensory to psychological and behavioural approaches including physical exercise, environmental interventions, music therapy, light therapy, aromatherapy, massage, multisensory stimulation, psycho-educational interventions for caregivers or care staff training. However, despite the public health problem posed by dementia, and more specifically the management of BPSD, there is a lack of well-designed studies evaluating the efficacy of the different nonpharmacological therapies.

Within this context, only a few studies have evaluated the use of rocking chairs for PwD. Modern rocking chairs may be suitable for long-term care because rocking, a rhythmically repeated movement, can contribute to psychosocial wellbeing. In this regard, it is a focus of attention to consider the therapeutic role of the Nordic Sensi® Chair (NSC) in the treatment of BPSD based on its ability to offer patients a sensory experience that brings the benefits of music therapy, therapeutic tactile stimulation, vestibular stimulation, and relaxation in an integrated way, especially those in nursing homes. This approach could facilitate the achievement of a balance between stimulation and sensory calm that would contribute to the effective management of BPSD.

The NSC (Wellness Nordic A/S, Humlebaek, Denmark) is an electrically operated rocking chair with built-in MusiCure music composed by Niels Eje. It is equipped with an integrated audio system with music recording based on more than 15 years of research on the calming and mentally stimulating effect of sound. The NSC has three different programs: Relax for deep relaxation, Refresh for recovery and Comfort for gentle relaxation. A 5 kg fiber blanket increases the feeling of security and relaxation, while helping users to perceive their own body. In addition to musical programming, the NSC provides predefined tactile stimulation and rocking motion, for a relaxing multi-sensory experience. All settings can be easily customized at the touch of a button.

The use of music in PwD, carried out on different stages of the disease, is based on the ancestral link between sounds and the human being and its potential to evoke emotions experienced throughout their lives, while generating states of calm and relaxation. This fact can be used to maximum benefit, as music can become a way of expressing their emotions in daily life, thus preventing the onset of anxious, agitated or even aggressive behaviour. Another way to increase the comfort of PwD is to provide tactile stimulation that could activate higher-order brain structures, such as the hypothalamus. As a result, patients would feel less anxious and calmer. Vestibular stimulation is very powerful as a tool to help regulate arousal levels to enable self-calming and focused attention.

Study participants in this study are men and women with a diagnosis of dementia according to the criteria of the 11th edition of the International Classification of Diseases of the World Health Organization and/or probable Alzheimer´s disease (AD) according to the criteria of the National Institute on Aging Alzheimer's Association workgroups (NIA/AA). Patients were recruited from two nursing homes specialized in dementia care: Centro Residencial Almudena (Rincón de la Victoria, Málaga, Spain) and Residencia DomusVi Fuentesol (Alhaurín de la Torre, Málaga, Spain). Patients included in the study are clinically defined in stages 4 to 7 of the Reisberg Global Deterioration Scale (GDS).

Considering the variability reported in the literature of the clinical assessment instruments used in the present study, it was anticipated that a sample of 70 subjects (35 in each of the two groups) would allow detection, with 80% power and an anticipated effect size of 0.5, for the primary efficacy variable NPI-NH of a statistically significant difference in the mean of 2.5 points or more between the two study groups, assuming a standard deviation of 1.5 points.

The study includes the evaluation of care staff from both nursing homes who participated in the direct provision of care to the participating PwD. The degree to which the presence of BPSD disturbed the normal development of their professional activities is assessed.

The study protocol was approved by the Málaga Research Ethics Committee (NSC-DEMEN study protocol approved on April 25, 2022). A written informed consent was signed by patients who were able to give or their legal representative. Informed consent was also requested from care staff who participated in the study. The study followed the ethical standards adopted by the Declaration of Helsinki in its latest version (Fortaleza, Brasil, 2013) and was conducted in accordance with the standards of Good Clinical Practice, as described in the Tripartite Harmonized Standards of the International Conference on Harmonisation for Good Clinical Practice 1996.

Study design This was a 16-week randomized, parallel, single-blind, controlled, clinical trial (RCT). After assessments for eligibility PwD were randomly assigned to two groups of equal size: a treatment group that received three times a week one session per day of 20 minutes in the Relax for deep relaxation program of the NSC and a control group that did not participate in the activity mentioned for the treatment group, but received, at the same time and duration, the care and activities that were part of the daily routines of the center, including group sessions of cognitive stimulation, training in activities of daily living or communication training. The research team evaluating the study results was blinded to the group assigned to the patients. An anonymized data base was generated. The safety of the intervention was closely monitored.

The 16-week study extension included a first pre-treatment period of 2 weeks' duration prior to the start of the intervention to establish the baseline, followed by a second 12-week treatment period with the use of the NSC and, finally, a third post-treatment period conducted 2-week after completion of the intervention. Participant assessments were conducted at four time points: at baseline, at weeks 6 and 12 of the treatment period, and at week 16 after the washout period.

Upon entry into the study, PwD who met the inclusion criteria were randomized to the treatment group or the control group. Randomization was carried out by blocks generating random numbers with repetition, one per block. Randomization numbers were assigned sequentially for all study participants.

Intervention For the purposes of this study, the NSC deep relaxation program (Relax Program) was used. The Relax Program lasts 20 minutes, during which the backrest descends to a semi-reclined position that is maintained throughout the program. The chair has also a footrest that can be raised and lowered. At the end of the program, the backrest returns to the sitting position. At the same time that the chair is rocking in a linear direction, the patient perceives the automatic relaxation music along with tactile stimulation on the back.

In both nursing homes, the treatment was carried out on weekdays, during the day shift. The chairs were placed in a quiet and separate space from the rest of the living areas intended exclusively for the treatment sessions, so there was no interference with the intervention. In each nursing home PwD were always introduced to the chair by the same nurse assistant who was specifically recruited and trained for the study. To facilitate the adaptation to the therapeutic process, participants were carefully introduced to the chair, e.g. just suggesting them sit down the first time, carefully rock the second time, start of the full program session the third time. During the treatment session, the nurse assistant remained seated next to the patient, ensuring that the user was relaxed and comfortable. Each PwD had their own schedule of rocking chair use throughout the study.

Outcomes measures Primary efficacy outcome was the Neuropsychiatric Inventory-Nursing Home (NPI-NH). Secondary efficacy outcomes were Cohen-Mansfield Agitation Inventory (CMAI) and Cornell Scale for Depression in Dementia (CSDD).

Statistical analysis A Mixed Effects Model Analysis for Repeated Measurements (MMRM) was carried out in order to evaluate changes in neuropsychiatric, cognitive, and functional scores and to handle missing value in some of the follow-up assessments. The effect of time (between the mean baseline measurements and each time point), treatment and treatment by time interactions were evaluated. All analyses were controlled for demographic and clinical characteristics that approached significance on univariate analysis. Post hoc analyses for multiple comparisons were conducted using Bonferroni´s correction. Cohen's d standardized effect sizes were calculated and defined as small d=0.20, medium d=0.50 and large d=0.80 [30].

The main efficacy analysis was based on the Intent-to-Treat (ITT) population using a Last Observation Carried Forward (LOCF) imputation. This ITT-LOCF population was pre-defined as all randomized patients who received at least one week of the Nordic Sensi® Chair treatment and had a baseline and at least one post-baseline assessment for the primary efficacy variable on treatment.

Statistical analysis was performed with a significance of p≤0.05. SPSS Statistics version 25.0 (IBM Corporation, Armonk, New York, USA) was used for the analyses.