Altered somatosensory temporal discrimination in chronic non-specific low back pain patients with central sensitization-related features: a cross-sectional study.

BACKGROUND: Central sensitization (CS) involves impaired inhibitory control and maladaptive neuroplasticity, resulting in altered sensory processing beyond nociceptive pathways. This study examined whether CS-related features are associated with impaired somatosensory temporal discrimination threshold (STDT) and its relationship with pain catastrophizing and disability in patients with chronic non-specific low back pain (cNSLBP). METHODS: Patients with cNSLBP were classified with or without CS-related features and compared with age- and sex-matched healthy controls (n = 37 per group). STDT was assessed at both the lumbar region and the hand. Pain catastrophizing, emotional status, and disability were evaluated using the Pain Catastrophizing Scale, the Hospital Anxiety and Depression Scale, and the Roland-Morris Disability Questionnaire. Between-group comparisons and correlation analyses were performed with adjustment for potential confounders. RESULTS: Patients with CS-related features demonstrated significantly prolonged STDT at both the lumbar region (F[2,101] = 33.80; P < 0.001; partial η2 = 0.401) and the hand (F[2,101] = 50.20; P < 0.001; partial η2 = 0.499) compared with patients without CS-related features and healthy controls. Lumbar STDT was associated with both pain catastrophizing (r = 0.529; P = 0.001) and disability (r = 0.343; P = 0.038), whereas hand STDT was associated exclusively with pain catastrophizing (r = 0.330; P = 0.046). CONCLUSIONS: CS-related features in cNSLBP are associated with impaired somatosensory temporal discrimination at both the lumbar region and the hand, suggesting that non-nociceptive temporal processing deficits may reflect a generalized alteration in central sensory processing rather than a localized phenomenon.