Neurological Symptoms and Comorbidities in Patients with Ankylosing Spondylitis.

Background/Objective: This study aimed to determine the prevalence of neurological symptoms and findings in patients with Ankylosing Spondylitis (AS) and to evaluate their relationship with disease activity. Methods: A total of 86 patients diagnosed with AS underwent a structured neurological examination including assessment of mental status, cranial nerves, motor system, deep tendon reflexes, pathological reflexes, and cerebellar/extrapyramidal functions. Sensory deficits and motor weakness were recorded. Orthostatic hypotension was evaluated as a clinical marker of autonomic involvement. Insomnia symptoms and neuropathic pain features were assessed clinically. Disease activity was quantified using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Associations between neurological findings, BASDAI scores, and inflammatory parameters were analyzed. Results: Motor weakness was observed in 5% of patients. Sensory deficits were present in 31% and orthostatic hypotension in 23% of patients. Insomnia symptoms were reported by 51% and neuropathic pain features by 53% of participants. A highly significant association was found between insomnia and neuropathic pain (p < 0.001). BASDAI scores were significantly higher in patients with insomnia, orthostatic hypotension, and sensory deficits (p = 0.004, p = 0.014, and p < 0.001, respectively). No significant association was observed between Anti-Tumor Necrosis Factor therapy and sensory deficits, and no significant correlation was demonstrated between neurological findings and C-reactive protein/Erythrocyte Sedimentation Rate values (p > 0.05). Conclusions: Neurological symptoms are common in AS and are associated with higher disease activity, without parallel changes in inflammatory markers such as CRP and ESR. Systematic evaluation of these symptoms may facilitate earlier identification of subgroups with a higher disease burden and inform individualized follow-up and management strategies.