Diabetic polyneuropathy (DPN) is one of the most common chronic complications of diabetes mellitus and is characterized by peripheral nerve damage caused by long-term hyperglycemia. Progressive sensory loss and impairment of proprioception may lead to balance disturbances, gait instability, and an increased risk of falls. Neurofilament Light Chain (NfL) has emerged as a potential biomarker of neuroaxonal injury in several neurological disorders.
The aim of this observational cross-sectional study is to investigate the relationship between serum Neurofilament Light Chain (NfL) levels and neuropathy severity, balance performance, and fall risk in patients with diabetic polyneuropathy. Neuropathy severity will be evaluated using the Michigan Neuropathy Screening Instrument (MNSI) and electrophysiological findings, while balance performance and fall risk will be assessed using the Berg Balance Scale and the Falls Efficacy Scale-International (FES-I).
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Neuropathy due to causes other than diabetes (e.g., vitamin B12 deficiency, hypothyroidism, alcohol abuse, chemotherapy) Renal dysfunction (eGFR < 60 mL/min/1.73 m²) Active infection or malignancy Inflammatory or autoimmune neurological diseases Central nervous system disorders (e.g., stroke, multiple sclerosis) Lumbar radiculopathy or peripheral entrapment neuropathy Severe visual impairment or balance disorders affecting testing Pregnancy Cognitive impairment preventing completion of questionnaires Patients with isolated small fiber neuropathy without electrophysiological evidence of large fiber involvement