Trait anxiety and sensory processing profile characteristics in patients with non-specific chronic low back pain and central sensitisation - A pilot observational study.

INTRODUCTION: People with non-specific chronic low back pain (NSCLBP) and central sensitisation (CS) exhibit sensory processing alterations, somatosensory hypersensitivity and differences in the brain's emotional networks. The concept that CS relates to pre-morbid trait sensory processing and anxiety characteristics is unknown. The aims of this pilot observational study were to test concept plausibility in a NSCLBP population with central sensitisation by investigating: 1) the range of Central Sensitisation Inventory scores, to determine the extent of symptoms of central sensitisation, 2) whether there are identifiable patient characteristics of trait anxiety and trait sensory profile differences; and 3) whether potential relationships exist between trait anxiety, trait sensory profiles and the extent of symptoms of central sensitisation.

METHODS: People with NSCLBP and CS were recruited from physiotherapy outpatient clinics in New Zealand and the United Kingdom. Outcomes included the Central Sensitisation Inventory (CSI), Adolescent/Adult Sensory Profile and the State/Trait Anxiety Inventory (trait section) with the Marlowe Crowne Sociable Desirability Scale. Descriptive and non-parametric tests for correlation were used to analyse the data, p=<0.05.

RESULTS: Of the 21 people recruited, 16 (76.2%) had CSI scores ≥40 in association with 1) an abnormally high prevalence of extreme scores of a) high trait Sensory Sensitive, Sensation Avoiding and Low Registration sensory profiles and b) low trait Sensation Seeking profile, 2) high trait anxiety sub-types and 3) minimal low trait anxiety. Moderate correlations were identified between trait sensory profiles and 1) CS pain (Sensory Sensitive R = 0.57, p < 0.01, CI = 0.07 to 0.88, p < 0.01, Sensation Seeking R = -0.47, p < 0.05, CI = -0.72 to -0.02) and 2) trait anxiety (Sensory sensitive: R = 0.65, p < 0.01, CI = 0.27 to 0.91) and Low Registration (R = 0.49, p < 0.05, CI = 0.03 to 0.84). The CSI scores moderately correlated with trait anxiety (R = 0.63, p < 0.01, CI = 0.22 to 0.86).

CONCLUSION: These results provide concept plausibility that the extent of CS pain in people with NSCLBP might be associated with pre-morbid trait anxiety sub-types and abnormal trait sensory processing profiles. A larger study to confirm the findings is warranted.