Assessing insomnia in pain – Can short be good?
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Pekka Mäntyselkä
In the present issue of the Scandinavian Journal of Pain, Dragioti and co-authors report on the factor structure and psychometric properties of the 7-Item Insomnia Severity Index (ISI) with patients of a pain clinic [1]. They suggest that an even shorter 4-item version of the Insomnia Severity Index could effectively evaluate insomnia in chronic pain patients.
1 The reciprocal association between pain and insomnia
The association between pain and sleep disorders has been established [2, 3, 4]. A systematic review some years ago revealed clearly that chronic low back pain was associated with several aspects of sleep quality during the preceding night [2]. The review could not conclude that impaired sleep affects low back pain. However, a recent study with chronic low back pain patients showed that in addition to pain affecting sleep quality, higher pain intensity was predicted by difficulty in falling asleep, waking after sleep onset and low sleep efficiency [3].
This year a study was published which was based on combined data from a controlled clinical trial dealing with musculoskeletal pain. It showed that changes in reported sleeping difficulties three months from the baseline predicted a change in pain 12 months from the baseline [4]. A reverse association, although weaker, was found as well. Thus, current scientific evidence indicates that the association between sleep quality and pain is bidirectional. Furthermore, these studies show that sleep quality in relation to pain complaints is increasingly important and of interest in pain research.
2 Insomnia scales – there are many available but it is not easy to choose between them
In general, there are sleep questionnaires aplenty. The Pittsburgh Sleep Quality Index (PSQI) and the Medical Outcomes Study (MOS) Sleep Scale are perhaps among the most commonly used measures. The validity, reliability and factor structure of these scales have been evaluated also among patients with chronic pain, and both are regarded as feasible also in this group of people [5]. The Karolinska sleep questionnaire [6] and the Basic Nordic Sleep Questionnaire (BNSQ) [7] are also used in relation to some pain symptoms but their feasibility, particularly among patients with chronic pain, has not been assessed.
The Insomnia Severity Index (ISI) is one of the most widely used validated insomnia scales [8]. It has seven items that assess different impairments caused by insomnia during the preceding two weeks: difficulty falling asleep; difficulty staying asleep; waking up too early; satisfaction with sleep; sleep interference with day-time functioning; noticeability of sleep impairment and distress caused by insomnia. Compared with many commonly used scales, the ISI is short. It has been found to be feasible as a method in detecting insomnia among patients with low back pain, with good sensitivity and specificity compared with the PSQI [9]. Hence, the findings arising from the previous studies support the need for further studies in assessing the use of the ISI in chronic pain.
3 Dreams and reality with sleep scales
The article by Dragioti and co-authors assessed the psychometric properties of the Swedish version of the ISI among 269 men and 567 women who were suffering from chronic pain and were referred to the pain and rehabilitation centre of Linkoping University Hospital [1]. The factor structure was analyzed using explanatory factor analysis (EFA) and confirmatory factor analysis (CFA). Furthermore, in order to identify a model with adequate fit, several CFA models were applied. This process resulted in a suggestion of a scale with four items. Thus, three items were omitted due to their low communalities; low item-total correlations and CFA fit indices of the resulting models. The omitted items included difficulty falling asleep, a problem of waking up too early and notice ability of a sleep problem. The results showed even better fit to the data after exclusion of these three items from the original 7-item version of the ISI. In contrast, the remaining four items related to insomnia (maintenance, satisfaction, interference and distress) proved to play well together and better without the other three items.
Two of the items omitted from the proposed 4-item scale were problems with falling asleep and disrupted sleep in the early hours. They are common symptoms related to insomnia detected in a clinical context. They are also common symptoms in depression. The authors emphasize that these two features of insomnia had the lowest variation in their sample, but the results do not exclude them as meaningful and important symptoms. Therefore, in clinical work, it must be stressed that none of the results obtained from questionnaires are themselves a basis for diagnostic assessment; screened problems with sleeping warrant deeper assessment of the patient and a proper diagnostic and therapeutic approach.
The suggested ISI-4 short sleep scale investigated in the study by Dragioti and co-authors seems to be a feasible and at least very promising tool in screening for insomnia in a clinical examination of chronic pain patients [1]. Moreover, it may prove to be a suitable instrument in assessing the severity of insomnia in epidemiological and clinical research. Several questions still need to be answered after the present study, which focuses merely on the factor structure and psychometric properties. What is the real accuracy of this 4-item scale in detecting insomnia? What are its specificity and sensitivity? This study was based on a sample of chronic pain patients from a Swedish pain clinic. The results may not be generalized to other populations or different types of patients.
The need for a reasonably short, valid and feasible instrument for pain-related insomnia detection and assessment is evident. After all, the present study exploring the properties of the Swedish version of the Insomnia Severity Index indicates that further assessment of clinical and research use of this suggested shorter 4-item scale is worthwhile.
DOI of refers to article: http://dx.doi.org/10.1016/j.sjpain.2015.06.001.
References
[1] Dragioti E, Wiklund T, Alföldi P, Gerdle B. The Swedish version of the insomnia severity index: factor structure analysis and psychometric properties in chronic pain patients. Scand J Pain 2015;9:22–7.Search in Google Scholar
[2] Kelly GA, Blake C, Power CK, O’keeffe D, Fullen BM. The association between chronic low back pain and sleep: a systematic review. Clin J Pain 2011;27:169–81.Search in Google Scholar
[3] Alsaadi SM, McAuley JH, Hush JM, Lo S, Lin CW, Williams CM, Maher CG. Poor sleep quality is strongly associated with subsequent pain intensity in patients with acute low back pain.Arthritis Rheumatol 2014;66:1388–94.Search in Google Scholar
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[6] Nordin M, Åkerstedt T, Nordin S. Psychometric evaluation and normative data for the Karolinska sleep questionnaire. Sleep Biol Rhythm 2013;11:216–26.Search in Google Scholar
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© 2015 Scandinavian Association for the Study of Pain
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Articles in the same Issue
- Editorial comment
- Editorial comment on Helen Richardson’s and Stephen Morley’s study on “Action identification and meaning in life in chronic pain”
- Original experimental
- Action identification and meaning in life in chronic pain
- Editorial comment
- Editorial comment on Karlsson et al. “Cognitive behavior therapy in women with fibromyalgia. A randomized clinical trial”
- Clinical pain research
- Cognitive behaviour therapy in women with fibromyalgia: A randomized clinical trial
- Editorial comment
- Assessing insomnia in pain – Can short be good?
- Observational study
- The Swedish version of the Insomnia Severity Index: Factor structure analysis and psychometric properties in chronic pain patients
- Editorial comment
- Reliability of pressure pain threshold testing (PPT) in healthy pain free young adults
- Observational study
- Reliability of pressure pain threshold testing in healthy pain free young adults
- Editorial comment
- Qualitative research in complex regional pain syndrome (CRPS)
- Topical review
- Building the evidence for CRPS research from a lived experience perspective
- Editorial comment
- Complex role of peroxisome proliferator activator receptors (PPARs) in nociception
- Original experimental
- Systemic administration of WY-14643, a selective synthetic agonist of peroxisome proliferator activator receptor-alpha, alters spinal neuronal firing in a rodent model of neuropathic pain
- Editorial comment
- Evaluation of pain in children with communication difficulties: r-FLACC translated and validated in Nordic languages
- Clinical pain research
- Assessment of pain in children with cerebral palsy focused on translation and clinical feasibility of the revised FLACC score
- Clinical pain research
- The revised FLACC score: Reliability and validation for pain assessment in children with cerebral palsy
- Editorial comment
- Coping with painful sex – A neglected female problem
- Clinical pain research
- Coping with painful sex: Development and initial validation of the CHAMP Sexual Pain Coping Scale
- Original experimental
- Spatial summation of thermal stimuli assessed by a standardized, randomized, single-blinded technique
