Alterations in sensory and motor nerve conduction associated with age and osteoarthritis in cats are correlated with functional impairment and somatosensory sensitization

Abstract

Abstract Feline somatosensory impairments associated with aging and osteoarthritis (OA) can be quantified through quantitative sensory testing and nerve conduction (NC). This prospective, randomized and blinded study aimed to compare NC in young healthy (CTRL, n  = 6) and older OA (OLD, n  = 12) cats. Under temperature-controlled general anesthesia, amplitude and conduction velocity (CV) of mixed tibial/sciatic and ulnar nerves were measured. Structural changes (radiographic score), functional alterations [MI-CAT(V)], neuro-sensitization [paw withdrawal threshold (PWT); and response to mechanical temporal summation (RMTS)] were assessed. Data distribution determined tests for inter-group comparison, and outcome correlations (α = 5%). OLD cats presented higher radiographic and MI-CAT(V) scores, but lower PWT, RMTS, motor CV (–23%), motor (–35%) and sensory (–45%) amplitudes compared to CTRL. Functional alterations correlated strongly with structural changes ( r  = 0.74, p  < 0.001) and age ( r  = 0.90, p  < 0.001), and moderately with neuro-sensitization ( p  < 0.016). Radiographic and MI-CAT(V) scores correlated negatively with (distal) motor CVs ( p  < 0.044), and with some motor and sensory amplitudes ( p  < 0.028). The PWTs correlated positively to motor CVs ( p  < 0.045). Older OA cats exhibited NC alterations correlated with neuro-sensitization and higher than expected with age alone.