The cognitive impact of chronic low back pain: Positive effect of multidisciplinary pain therapy

AbstractObjectivesLittle is known about the affected cognitive problems in chronic low back pain patients. For this patient cohort research mostly focused on memory of pain, rather than cognitive difficulties related to pain. Chronic pain may be associated with specific (yet undefined) cognitive deficits that affect everyday behaviour. We set out to compare the cognitive function of patients with chronic low back pain (cLBP) in the course of multidisciplinary pain treatments before and after therapy.MethodsThirty-three patients with cLBP and 25 healthy controls between 20 and 70 years were recruited into the study. The inclusion criteria for patients were: (1) a history of at least 12 weeks of chronic myofascial low back pain without radicular pain sensation before enrolment; (2) grade II and higher chronicity according to von Korff; (3) no opioid medication. The patients recruited had a mean pain duration of 7.13 ± 7.16 years and reported a mean pain intensity of 6.62 ± 2.04 (visual analogue score, VAS). Their mean back function according to the Funktionsfragebogen Hannover (FFbH, a questionnaire comparable with the Health Assessment Questionnaire) was 52.39 ± 20.23%.At three time points (before therapy, 3 weeks and 6 months after therapy) the study subjects were assessed prospectively with a battery of visual memory tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB). These included choice reaction time (CRT), pattern recognition memory (PRM) and spatial span (SSP). In parallel, the Trail-Making Test (TMT-A, TMT-B) and the Wechsler Adult Intelligence Scale (WAIS-III) were used to evaluate intelligence and cognitive flexibility.ResultsAt the beginning of MDPT (T1), it took patients with cLBP significantly longer than HC to complete TMT-A (38.29 ± 19.99 s vs 30.25 ± 14.19 s, p = 0.047) and TMT-B (72.10 ± 26.98 s vs 55.99 ± 22.14 s, p = 0.034). There were no significant differences between patients and HC in CRT, PRM and SSP. Three weeks (T2) and 6 months (T3) after MDPT, TMT-A reaction time of patients significantly improved by 6.5 s and 8.1 ms (38.3 ±19.9 s vs 31.8 ±12.3 s, p = 0.02 and 31.8 ± 12.3 s vs 30.2 ± 8.9 s, p = 0.021, respectively). The patients’ working memory was also better 6 months after MDPT (48.8 ± 11.1% at T1, 51.2 ±11.9% at T2, 57.1 ±10.9% at T3, p = 0.008). Significant correlations among pain, depression/anxiety, medication and neuropsychological tests were found.ConclusionsThese findings show that patients with cLBP have slowed speeds of information processing and working memory, but no alteration in attention and recognition memory. There are clearly interactions of cognitive function with pain, depression, anxiety, and medication. MDPT may improve the impaired cognitive function of patients with cLBP.ImplicationHealth professionals should contemplate the results from this study when planning therapy strategies especially when prescribing pain medications such opioids to patients with chronic low back pain.

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Comparative Associations of Working Memory and Pain Catastrophizing With Chronic Low Back Pain Intensity

Physical Therapy ◽

10.2522/ptj.20150335 ◽

2016 ◽

Vol 96 (7) ◽

pp. 1049-1056 ◽

Cited By ~ 10

Author(s):

Corey B. Simon ◽

Trevor A. Lentz ◽

Mark D. Bishop ◽

Joseph L. Riley ◽

Roger B. Fillingim ◽

...

Keyword(s):

Working Memory ◽

Low Back Pain ◽

Back Pain ◽

Pain Intensity ◽

Chronic Low Back Pain ◽

Pain Catastrophizing ◽

Future Research ◽

Low Back ◽

Cross Sectional ◽

Daily Pain

Abstract Background Because of its high global burden, determining biopsychosocial influences of chronic low back pain (CLBP) is a research priority. Psychological factors such as pain catastrophizing are well established. However, cognitive factors such as working memory warrant further investigation to be clinically useful. Objective The purpose of this study was to determine how working memory and pain catastrophizing are associated with CLBP measures of daily pain intensity and movement-evoked pain intensity. Design This study was a cross-sectional analysis of individuals with ≥3 months of CLBP (n=60) compared with pain-free controls (n=30). Method Participants completed measures of working memory, pain catastrophizing, and daily pain intensity. Movement-evoked pain intensity was assessed using the Back Performance Scale. Outcome measures were compared between individuals with CLBP and those who were pain-free using nonparametric testing. Associations were determined using multivariate regression analyses. Results Participants with CLBP (mean age=47.7 years, 68% female) had lower working memory performance (P=.008) and higher pain catastrophizing (P<.001) compared with pain-free controls (mean age=47.6 years, 63% female). For individuals with CLBP, only working memory remained associated with daily pain intensity (R2=.07, standardized beta=−.308, P=.041) and movement-evoked pain intensity (R2=.14, standardized beta=−.502, P=.001) after accounting for age, sex, education, and interactions between pain catastrophizing and working memory. Limitations The cross-sectional design prevented prospective analysis. Findings also are not indicative of overall working memory (eg, spatial) or cognitive performance. Conclusion Working memory demonstrated the strongest association with daily pain and movement-evoked pain intensity compared with (and after accounting for) established CLBP factors. Future research will elucidate the prognostic value of working memory on prevention and recovery of CLBP.

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WAVELET ANALYSIS OF LOW BACK SURFACE EMG SIGNALS SUBJECT TO UNEXPECTED LOAD

Journal of Mechanics in Medicine and Biology ◽

10.1142/s0219519404001004 ◽

2004 ◽

Vol 04 (03) ◽

pp. 389-400 ◽

Cited By ~ 1

Author(s):

M. H. POPE ◽

N. D. PANAGIOTACOPULOS ◽

W. STIELAU ◽

K. FRIESEN ◽

J. S. LEE

Keyword(s):

Low Back Pain ◽

Back Pain ◽

Reaction Time ◽

Chronic Low Back Pain ◽

Erector Spinae ◽

Back Surface ◽

Initial Reaction ◽

Clinical Test ◽

Low Back ◽

Normal Subject

This study reports a new technique for the analysis of electromyographic signals from the low back muscles. More specifically, the effect of unexpected load on a normal subject and a subject with chronic low back pain was determined and quantified using wavelet based analysis (Morlet wavelet). The analysis was performed using a Wavelet software system, subsequently referred to as PSCW. The system identified automatically, accurately, and in a uniquely reproducible manner the time response of the erector spinae muscle. The exact number of responses as well as their corresponding time and amplitude were determined and tabulated. It was observed that the initial reaction time for the normal subject was faster than the reaction time for the subject chronic low back pain. The importance of this observation may help in the understanding of the physiology of the neuromuscular system associated with low back spine disorders. It is believed that an occupational and clinical test based on this observation that could give an accurate assessment of the status of low back disorder could be designed. Based on this assessment a rehabilitation program could be developed with the objective of improving the condition of a spine disorder (decrease the initial response time) by muscle strengthening.

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