[The nervous system and communication: polyneuropathy and the role of the peripheral nervous system].

The central nervous system (CNS) processes information, coordinates movements, and enables communication-both within the body and with the environment: Perception and response to sensory impressions are controlled by the brain, with afferent and efferent pathways passing through the spinal cord. The peripheral nervous system (PNS) mediates between the environment and the CNS. As we age, the PNS undergoes changes, resulting in a weakening of muscle reflexes and proprioception. This must be distinguished from polyneuropathies (PNP), which are pathological changes in the PNS. The causes are manifold: in addition to metabolic, immune-mediated, hereditary, toxic, and infectious etiologies, polyneuropathies can be a manifestation of systemic diseases. Neuropathies associated with diabetes, monoclonal gammopathies, and malignancies are more common in older people, and the proportion of cryptogenic neuropathies also increases with age. PNPs contribute to impaired mobility and an increased risk of falls, which necessitates the assessment of functional abilities. Pain and sensory disturbances have a negative impact on activities of daily living. As a result, communication with the living environment is impaired. A geriatric approach enables not only an accurate diagnosis but also comprehensive therapy tailored to individual needs.