Evaluation of wheelchair satisfaction with wheelchair initial-final sitting pressure

Abstract

Background

Wheelchair users spend a significant portion of their daily time sitting. This can lead to postural changes, imbalances in sitting pressure, and discomfort. Regulating sitting pressure and providing proper postural support is important not only for preventing pressure sores but also for increasing user satisfaction and quality of life.

Objective

This study aims to evaluate user satisfaction by comparing initial and final measurements of seating pressure in wheelchairs with postural alignment.

Methods

Seventeen wheelchair users with a mean age of 45 ± 10.7 years participated in the pilot study. Seating pressures were measured using pressure sensors at baseline and after intervention. User satisfaction was measured using a standard questionnaire assessing comfort, ease of use, and perceived safety.

Findings

Significant improvements were observed between baseline and final sitting pressures, particularly in the posterior regions (p < 0.005; Cohen’s d = 0.59–0.78). Increases were observed in user satisfaction in the areas of comfort and perceived safety, but the changes were not statistically significant (p > 0.05).

Conclusion

Balancing seating pressure with a pressure-regulating wheelchair system may increase user comfort and satisfaction. Objective assessment of pressure distribution can help optimize wheelchair settings, thereby improving both safety and quality of life. Larger sample sizes and long-term follow-up studies are required.

Introduction

Wheelchair users (WUs) spend a significant portion of their daily time sitting. As the level of disability increases, this proportion can rise to 85%. ¹ Prolonged sitting can negatively affect muscle and bone health and, in conjunction with limited mobility, can lead to a decline in quality of life. ² Although wheelchairs increase mobility, postural changes associated with prolonged sitting can lead to imbalances in sitting pressure and the risk of pressure sores. ³ Prolonged sitting in this incorrect posture can affect user satisfaction and quality of life through pain, muscle tension, and discomfort. ⁴

Understanding the relationship between sitting pressure, posture assessment, and user satisfaction is crucial. In the literature, posture assessment is conducted by healthcare professionals through observation and self-report questionnaires, which involve subjective limitations.^5–7 New technological approaches enable objective and continuous monitoring of users through smart seating pressure and posture monitoring systems. These systems prevent both pressure sores and posture disorders. They also affect quality of life and user satisfaction.^5,8,9

The aim of this study is to investigate the relationship between user satisfaction and quality of life by evaluating posture using initial and final sitting pressure measurements in WUs. This will explore the effect of sitting pressure and posture adjustments on user comfort and safety.

Material and method

Ethical approval

This pilot study was approved by the Necmettin Erbakan University Health Sciences Scientific Research Ethics Committee (2021/2981). Signed informed consent was obtained from all participants. Data for this study were collected between February 2022 and March 2023. A Clinical Trial approval number (NCT04751123) was obtained from the Clinical Trials Service.

Participants

Participants’ demographic information (age, gender, education level, duration of illness, and whether they received physical therapy) was recorded during the initial interview. Participants were enrolled in the study using their own wheelchairs, which were not prescribed according to a specific methodology. After obtaining a medical history, each participant was allowed to rest on a mat for 20 min to stabilize their body pressure and posture before beginning the measurements. Individuals diagnosed with poliomyelitis sequelae (n = 7), spinal cord injury (n = 6), cerebral palsy (n = 2), and amputation (n = 2) were included in the study.

The study included patients aged 18 years and older, with an average age of 45 ± 10.69, consisting of 10 men and 7 women, with polio sequelae, spinal cord injury, cerebral palsy, and amputation, who had been using a wheelchair for at least 3 months, while those who had experienced pressure ulcers in the past year were excluded.

A cushion consisting sensors, two of under the thighs and two of under the buttocks, was placed on the wheelchair. The patient was then asked to sit on this pressure pad. The initial pressure was recorded. Care was taken to ensure that the patient’s hip and knee angles were at 90° and that their hands were on their knees. After the patient had been seated in the wheelchair for 1.5 h (90 min), pressure readings, the WHOQol-Bref Scale, and the Wheelchair Skills Test (WST) were re-taken.

Evaluations

Pressure assessment

Data was recorded in kilograms by placing four pressure sensors in four areas under the hips and legs. ¹⁰ The sensors operate on +5V DC voltage and can measure weights up to 100 kg. These sensors are a structure called a load cell, which converts mechanical force into an electrical resistance value. This structure measures the strain force dependent on weight through a wheatstone bridge. Since the load sensor outputs produce very small electrical signals when the mechanical load changes, the relevant data was amplified using an appropriate electrical amplifier and transferred to the electronic card. Additionally, since load cell data is of an analog nature, it is converted to a format compatible with the electronic board using a 24-bit Analog-to-Digital Converter (ADC). ¹¹ The system produces outputs at different resistance levels when the patient’s position changes. Thus, the patient’s pressure distribution can be observed on the screen using the defined references on the electronic board (Figure 1).

Figure 1.

Pressure assessment.

The functional independence measure (FIM)

The FIM is a comprehensive assessment scale that measures the extent to which an individual is independent in basic physical and cognitive activities of daily living. The total score ranges from 18 to 126 and consists of 18 items. The scale consists of two main sections assessing physical and cognitive functions.^12,13

craig Handicap Assessment and Reporting Technique (CHART)

Designed by Whiteneck ¹⁴ and colleagues to measure the level of participation (handicap) of people with spinal cord injury in a community setting, the CHART is administered as a semi-structured interview to the patient or their next of kin. The scale measures questions divided into five categories: physical independence, mobility, social integration, economic self-sufficiency, and occupation. Raw scores are converted to a scale score ranging from 0 to 100 on each scale, where a score of 100 indicates no handicap, a value achieved by nearly all healthy, working-age adults; a score of 0 indicates complete handicap. The maximum total CHART score is 500, indicating no handicap. ¹⁵

Wheelchair Skills Test for manual wheelchair users (WST)

The WST is a 32-item objective test of wheelchair skills. ¹⁴ It assesses the same 28 skills as the WST-Q and is scored in the same way. Because some users use manual wheelchairs and others use electric wheelchairs, the two will be assessed using different forms.^16,17

World Health Organization Quality of Life Scale (WHOQOL)

This scale, which has a long form with 100 questions and a short form with 26 questions (WHOQOL-BREF), was developed within the framework of a multicenter project that began in 15 centers and later included more than 40 countries, including Turkey. Its multicenter development process and cross-cultural validation make this scale reliable. The long form consists of six dimensions: physical, psychological, social relations, independence level, environment, and personal beliefs. The short scale covers physical, psychological, social relations, and environment and also includes questions specific to each culture. ¹⁵

Statistical analysis

IBM SPSS Statistics 29.0 for Windows was used for all statistical analyses. Mean, standard deviation, and percentage were used for demographic data. Parametric paired samples t-test was used to compare pre- and post-study pressure parameters of the groups. ¹⁸ Significance was set at p < 0.05.

Results

Table 1 provides a comprehensive overview of the demographic and clinical profile of the study cohort, including age, disease duration, disability type, educational background, and wheelchair characteristics.

Table 1.

Demographic information.

	Gender	N	X	SD
Age	Woman	7	42.57	8.03
	Man	10	46.70	12.34
Disease duration	Woman	7	36.14	7.81
	Man	10	22.70	21.43

	N	%
Disability type
Polio	7	41.2
Medulla spinalis injury	6	35.3
Serebral palsi	2	11.8
Amputee	2	11.8
Highest level of education
Primary school	7	41.2
Middle school	3	17.64
High school	3	17.64
University	4	23.52

Wheelchair type	Manuel N	Electric N	Manuel %	Electric %
	7	10	41.17	58.82

X: mean; %: percentage; N: number.

The differences in right posterior and total sitting pressure were considered both statistically significant (p < 0.001) and clinically significant (Cohen’s d > 0.7). The change in the left anterior and left posterior regions had a moderate effect size. The difference in the right anterior region was statistically insignificant (p = 0.110) and the effect size was small (d = 0.22), so it did not represent a clinically significant change (Table 2).

Table 2.

Comparison of initial and final seating pressures of WU.

Variables	Initial settling pressure X ± SD	Final seating pressure X ± SD	t-test	p*	Cohen’s d
Right front (kg)	12.47 ± 8.96	14.41 ± 8.91	−1.69	0.110	0.22
Right back (kg)	8.00 ± 5.30	12.17 ± 5.71	−6.07	0.000	0.74
Left front (kg)	11.11 ± 7.98	13.64 ± 6.79	−3.05	0.008	0.34
Left back (kg)	9.11 ± 6.58	12.47 ± 4.97	−3.66	0.002	0.59
Total weight (kg)	40.54 ± 15.10	44.69 ± 14.44	−7.78	0.000	0.78

*paired sample t-test, p < .05.

Effect sizes for all variables were very weak (d < 0.2), and p-values were insignificant. Changes over time did not produce clinically significant differences in the parameters measured in this study. In particular, the complete stability of the FIM and CHART scores (d = 0.000) suggests a short time period (Table 3).

Table 3.

Wheelchair Skills Test and WHOQol-Bref of WUs.

Variables	Initial settling pressure X±SD	Final seating pressure X±SD	t	p*	Cohen’s d
WHOQol-Bref Ölçeği	90.64 ± 3.69	90.52 ± 3.69	0.226	0.824	0.033
Wheelchair Skills Test (WST)	72.87 ± 3.92	73.33 ± 4.00	−0.842	0.667	0.118

X: mean, SD: standard deviation, p < .05, *paired sample t-test.

Discussion

This study evaluated the effectiveness of a system developed to balance sitting pressure in wheelchair users.^19,20 Findings demonstrated significant improvements in both the posterior and total pressure values. This type of balancing in sitting pressure is crucial for reducing the risk of pressure ulcers resulting from prolonged sitting, particularly in conditions such as spinal cord injury, cerebral palsy, or amputation. This study evaluated the optimal sensor placement and its response to an individual sitting routine in the WUs. The sensors were designed as an educational tool to remind individuals with paraplegia to perform pressure-reduction activities. ²¹ The number of sensors can be increased to achieve higher spatial resolution, providing greater opportunities to extract information about the sitter. Sitting pressure is considered a key factor in the formation of pressure ulcers, especially in individuals who maintain a fixed posture for extended periods. ²² The literature indicates that appropriate seating surface configuration is effective in both reducing mechanical load and increasing tissue perfusion. ²³ The increase in posterior pressure observed in our study suggests that the user is transitioning to a more upright sitting posture and shifting from preload to postural load, which is a positive development in terms of postural balance. No significant change was observed in WHOQOL-BREF, and WST scores. This finding suggests that short-term interventions will not have a significant impact on quality of life and functional independence. The sensitivity of quality of life measures such as WHOQOL-BREF to change, especially in chronic and neurological diseases, becomes evident with longer-term follow-up. ²⁴ Furthermore, it should be noted that quality of life is related not only to physical comfort but also to multidimensional factors such as social participation, environmental accessibility, and psychological state. ²⁵ The system used in our study not only measures sitting pressure but also regulates it, offering an intervention-based approach, unlike similar studies. Router et al. (2019) reported that monitoring pressure-reducing behaviors in wheelchair users is an effective strategy for individuals to recognize and adjust their sitting habits. ²⁶ The system presented in this study has not been validated, but it provides a technological answer to this need by providing both monitoring and balancing functions.

The study is limited by its small sample size and short follow-up period. Longer-term follow-up is important to demonstrate the system’s impact on quality of life and functional independence. Furthermore, the addition of behavioral analyses to measure how pressure-reduction strategies are integrated into individuals’ daily habits is recommended.

Conclusion

This study demonstrated that systems that regulate sitting pressures can improve pressure distribution by balancing postural loading in the short term. However, effective changes in parameters such as quality of life and functional measures require long-term, holistic approaches.