Perceiving less or perceiving unreliably? Disentangling thermosensory sensitivity and precision in the contexts of ageing and neuropathy

Abstract

Thermal perception is determined not only by sensitivity but also by precision. Yet, the latter is often overlooked in thermosensation and pain research. This study examined how ageing and diabetic polyneuropathy (DPN) affect these parameters and whether assessing both sensitivity and precision can aid in distinguishing patients from healthy controls. Using Bayesian hierarchical models, we estimated psychometric function thresholds (sensitivity) and slopes (precision) for cold detection, warm detection, cold pain, and heat pain stimuli delivered at the volar forearm, in a cross-sectional sample of 75 healthy adults (aged 21-80) and 33 patients with DPN. We also estimated these parameters separately for each participant and used the resulting estimates in classification analyses. Ageing was associated with elevated cold and warm detection thresholds, elevated cold pain thresholds, and reduced cold detection slope. Patients with DPN showed similar patterns: higher detection thresholds and lower cold detection slopes while pain-related parameters were largely unaffected. These findings indicate that ageing and neuropathy produce qualitatively similar changes in thermosensory function, particularly affecting cold detection. Classification based on single parameters successfully discriminated patients from controls, except when warm detection or heat pain slopes were used. Combining threshold and slope parameters for a given modality did not significantly improve classification accuracy but combining all parameters across all modalities led to the best performance, with excellent accuracy (AUROCC: .84, 95% CI [.75.91]). Modelling both thresholds and slopes provides a more comprehensive view of sensory decline and may enhance the detection of early or subtle sensory dysfunction. PerspectiveThis study shows that ageing and diabetic polyneuropathy produce strikingly similar thermosensory changes, affecting cold detection sensitivity and precision as well as warm detection sensitivity while largely sparing pain-related measures.