From: BMC Res Notes. 2010 Jul 13;3(1):190.
The incidence rate of whiplash injuries in Sweden is estimated to be 1.0-3.2/1000 /year. The injuries constitute a major health problem in Western society due to the large number of people with Whiplash associated disorder and the high economical costs associated with whiplash associated disorder. People with acute whiplash associated disorder, mainly complain of neck pain, stiffness, headache and dizziness. Other symptoms that may occur after the injury are fatigue, concentration and memory problems. Most subjects with acute whiplash associated disorder are reported to recover within three months of the trauma however, a significant number of persons experience symptoms several years after the accident. Persistent neck pain has been reported in 84-90% one to two year and in 55% 17 years after the injury.
It is still unclear why pain and related symptoms do not resolve after the expected time of healing and which factors are involved in the persistence of symptoms and impairments after the trauma. A bio-psycho-social model is often used to describe the complex interaction of physical and psychological factors in the development of chronic whiplash associated disorder. The long lasting problems after the injury may also interfere with occupational activities, the number of persons on sick-leave or unable to perform their ordinary duties six months after whiplash associated disorder have been reported to vary between 13 and 50%. In addition, chronic whiplash associated disorder may also affect leisure and daily life with social contacts and the total experience of life satisfaction.
Many studies of long-term problems after whiplash associated disorder have primarily focused on symptoms, especially neck pain in people seeking health care but fewer studies have investigated the long-term effects on activity/disability and life satisfaction. In addition, less is known about the differences between subjects who consider themselves as recovered and those who suffer from persistent disability. Sterling et al investigated post-traumatic stress in relation to disability on the Neck Disability Index during the first six months after whiplash injury. They found that persons who reported themselves to be recovered or to have mild disability six months post trauma reported decreased post-traumatic stress scores in comparison with early after the injury, whereas persons with moderate/severe disability reported persistent post-traumatic stress scores into the chronic stage.
In a scientific as well as in a clinical context, the need of studying subgroups of subjects has been proposed. Information about the characteristics of these groups may provide help to develop adequate treatments. Since the levels of disability seems to be of importance in whiplash associated disorder, this study aimed to assess the difference in symptoms, psychological factors and life satisfaction between subjects who were classified as recovered and those who suffered from mild/severe disability based on the Neck Disability Index. In addition, this study examines whether the Neck Disability Index is a clinically useful tool to classify whiplash disability.
Although previous studies have investigated disability in whiplash patients, to the authors knowledge this study is the first to investigate differences in pain intensity, symptoms, posttraumatic stress, depression, and life satisfaction between subjects with persistent disability and subjects classified as recovered in a “non-help-seeking” population long time after whiplash injury.
In the present study the Neck Disability Index was used to assess and to classify disability in according to a previous study. In their study of whiplash patients six months post trauma, the Neck Disability Index scores were slightly lower in comparison with the three subgroups in the present study. Regardless of the time difference between the two studies, it seems possible to assume that the character of disability in persons with whiplash associated disorder around half a year after the injury may persist for longer time. The results on the Neck Disability Index in our study also agree with the scores reported three years and 17 years after the injury.
In accordance with previous studies of whiplash associated disorder, neck pain was the most commonly reported symptom in the moderate/severe and the mild groups. These frequencies were close to results (55 %) reported 17 years after the injury. However, pain was also reported in the recovered group, but the frequencies of pain locations (neck, upper and lower back pain) were more equal. Among the whiplash related symptoms, cognitive deficits with poor concentration and poor memory were unexpectedly high both in the recovered group (25%) and in the moderate/severe and mild groups (60-93%). Since chronic pain, depression and post-traumatic stress may affect cognitive symptoms, these factors might have contributed to the cognitive disturbances in all groups in the present study.
The highest post-traumatic stress scores were reported in the moderate/severe group and the frequency of distinct post-traumatic stress reaction (36.3%) was clearly higher than reported in whiplash patients early after injury (13%). Some evidence for an association between greater post-traumatic stress and late whiplash syndrome has been shown. However, since the levels of post-traumatic stress were high especially in the moderate/severe group, these findings may support the recommendation of early diagnoses and treatment of acute stress to minimize the risk for long-lasting symptoms.
Chronic whiplash associated disorder may have a negative impact on quality of life. When comparing life satisfaction on the LiSat-11 between the three disability groups in our study with a large population-based Swedish reference group (2533 subjects), the mild and moderate/severe groups showed lower levels of life satisfaction. However, significant differences were found between the moderate/severe group and the recovered group in eight of eleven domains. Previous research has shown that depression influences outcome for quality of life in chronic whiplash associated disorder and the significantly higher BDI scores in the moderate/severe group may have contributed to their low life satisfaction. Moreover, the association between depression and non-recovered in the multivariate analysis indicates the importance of assessment and treatment of depression in whiplash associated disorder-patients.
This study has implications for clinicians. Although symptoms often are reported after whiplash injury, the activity levels may differ. Due to the complexity of whiplash associated disorder, the importance of identifying subgroups of whiplash associated disorder has been proposed in order to better tailor their treatment. In a previous study, Neck Disability Index was found to be the most sensitive instrument among several questionnaires to predict poor outcome. Our study adds to previous research: the Neck Disability Index seems to be a useful instrument for classifying whiplash subjects into subgroups. In general, we found that the group with moderate/severe disability reported high frequency of symptoms, high depression and post-traumatic stress scores and low level of life satisfaction. However, the recovered group also reported symptoms and post-traumatic stress scores, but these levels were not related to disability.
