Development and evaluation of neck pain and functional limitation scale: A validation study in the Asian context.
From: Indian J Med Sci. 2009 Oct;63(10):445-54
Neck pain is one of the most common problems in the population, which affects approximately 67% of individuals at some point of time in their lifetime. Regarding the 12-month prevalence of neck pain, previous research studies have reported it to range between 30% and 50%. Although it is not life threatening, it can cause a sense of being unwell and substantial level of disability due to pain and neck stiffness. This disability can affect the physical functioning of the patients, leading to sickness behavior and activity restrictions. In the general population, the 12-month prevalence of activity-limiting pain has been reported to vary from 1.7% to 11.5%.
The severity of neck pain and the related disability can affect daily social and functional activities, which may even involve emotional and psychological aspects. Thanks to the approval of the International Classification of Functioning, Disability and Health (ICF) by the World Health Assembly in 2001, neck pain and related consequences could be clearly understood and evaluated by a universal conceptual model termed as biopsychosocial health, which integrated the biomedical and societal models of functioning and disability. Hence, the outcome measures for any disease that predict the disease progress and response should carefully consider the biopsychosocial model involved in the evaluation of the disease process.
A few disease-specific outcome measurement tools that are available for assessing neck pain include neck disability index, neck pain and disability scale, Copenhagen neck functional disability scale, Northwick Park pain questionnaire, patient-specific functional scale self-reports with neck dysfunctions and the North American Spine Society cervical spine outcome assessment instrument. Interestingly, all the above-mentioned tools were developed considering the psychosocial aspects of western culture and were validated in the western context. These tools may have cultural bias and may be unsuitable for use in the Asian context because of the differences in the local cultural practices. Hence there was a need to develop a disease-specific outcome measurement tool for neck pain that reflects the local cultural practice. Thus, the neck pain and functional limitation scale was designed as a new outcome measurement tool to evaluate neck pain.
It is important that the newly developed outcome measurement tool must demonstrate reliability (consistency), validity (trueness) and responsiveness (the ability to detect change). If the results of the tool are valid, then it should measure the trait for which it was designed (content), be correlated to other measures of that trait (criterion) and must differentiate between the group with disease and the one without it. Hence the main aim of the present study was to create a new outcome measurement tool, neck pain and functional limitation scale, in order to assess the disability involved in neck pain and to report its reliability, concurrent validity and criterion validity.
Research on neck pain had shifted its focus away from the signs and symptoms. Rather, importance was laid on the specific effects of the symptoms on the patient’s functioning and daily life. The above facts were supported by a previous study which looked at neck function, physical function more holistically and at psychological function, which supported the reasons for inclusion of the multidimensional domains in the construction of neck pain and functional limitation scale. Therefore, the main 5 domains of neck pain and functional limitation scale are pain intensity, activities of daily living, functional domain, social domain and psychological domain. Each domain has four sub-items, which makes for a total of 20 items in the neck pain and functional limitation scale. The 5 main domains of the neck pain and functional limitation scale and the sub-items were framed from items generated from neck pain-focused group interviews, items generated from literature review and items generated from the information received from clinical specialists dealing with neck pain.
An initial neck pain and functional limitation scale questionnaire (consisting of 36 items) comprising of summarized items was prepared and was sent for a review. This review team consisted of 4 other senior physiotherapists specialized in musculoskeletal practice and a senior medical practitioner. The team came out with the final version of neck pain and functional limitation scale (20 items) after removing the unpopular items and adjusting the tool for domain and syntax. The main domains and each sub-item under every main domain in neck pain and functional limitation scale were presented as follows:
Domain 1 – Pain intensity: It consisted of 4 questions, which included neck pain rating, duration of neck pain, ability to manage neck pain and ability to tolerate neck pain.
Domain 2 – Activities of daily living (ADL): It consisted of 4 questions, which included dressing, head turning, television-viewing and carrying things.
Domain 3 – Social activities: It consisted of 4 questions, which were related to shopping, family relationships and interactions, traveling and recreational activities.
Domain 4 – Functional activities: It consisted of 4 questions, which included reading, using phone, looking up to search things above head level and work.
Domain 5 – Psychological factors: It consisted of 4 questions, which were related to sleeping, ability to concentrate, feeling of anxiousness and feeling of depression.
Previous studies that dealt with neck pain had identified rating of pain, duration of neck pain, ability to manage neck pain and the ability to tolerate neck pain as the important factors which were to be considered while assessing pain among patients with neck pain. Hence the pain intensity domain was supported with sub-items which included neck pain rating, duration of neck pain, ability to manage neck pain and ability to tolerate neck pain.
The physical factors associated with neck pain included heavy lifting, monotonous work tasks, static work posture, vibrations, repetitive jobs and a high work pace. However, the patients from the focused interview group identified activities such as turning head during driving, viewing television, carrying things and dressing as the main problems that resulted from their neck pain. These were included as items under the domain of activities of daily living.
Previous studies had pointed out that neck pain can affect social factors, which include shopping, family relationships and interactions, traveling and recreational activities. Hence these items were included to assess the effects of neck pain and disability within the social context. In the patient-specific focused group interview for neck pain, majority of the patients complained of neck pain while reading a newspaper or a book in a flexed neck position. Furthermore, previous studies had listed using phone, looking up to search things above head level and daily work as the main functional activities affected due to neck pain. Hence the functional activities domain consisted of 4 questions, which included reading, using phone, looking up to search for things above head level and normal daily work activities.
Previous research had shown a direct correlation between the pain level and the attention paid to psychosocial distress, especially anxiety and depression. Other psychological factors affected by neck pain were disturbed sleep due to pain, lack of ability to concentrate and focus, feelings of anxiety and depression. Disturbed sleep and sense of depression were commonly cited by the individuals in the neck pain focus group as disabling factors related with neck pain. Therefore, the psychological domain consisted of 4 questions, which included those related to sleeping, ability to concentrate and focus, and feelings of anxiousness and depression.
This study has some strength in that the subjects with neck pain recruited in the study represented a variety of cervical problems, ranging from cervical spondylosis to cervical disc prolapse. The recruitment of patients with both nonspecific neck pain and specific neck pain (a structural damage to the neck tissue) allowed the applicability of neck pain and functional limitation scale to various types of neck pathologies. Similarly, the age range of the patients who participated in this study also consisted of both younger and older age groups of patients. Hence it could be said that neck pain and functional limitation scale may be applied to different age groups. Strength may be accounted for by the process of designing the neck pain and functional limitation scale. Previous tools related with neck pain configured questionnaire items based on literature reviews and were compared with a patient-specific tool. The neck pain and functional limitation scale was designed by collecting information using patient-specific methods, expert opinions, along with the items supported scientifically through literature search.
The present study supported the validity of neck pain and functional limitation scale because the performance of the neck pain and functional limitation scale was comparable to the established standards of the neck bournemouth questionnaire. The study results suggested that the neck pain and functional limitation scale was a highly reliable outcome measurement tool to evaluate neck pain and underlying disability.
