Table 7.

Age-Related Changes in Nervous System and Their Impacts. ¹²⁹

Affected Nervous System	Deficits With Aging	Effects on Patient’s Daily Activity, Medication, and Surgery
Central nervous system (CNS, brain and spinal cord)	Volume of brain mass, number of synapses, and neurotransmitter concentrations. Cerebral electrical and metabolic activity. Changes in brain nerve fibers. Changes within the spinal cord (cervical spinal cord maintains it shape, but decreases in size). Modification of the bony spinal canal (shape and area of spinal cord are independent of spinal canal diameter).	Patient experience neurological dysfunction as a result of decrease neurotransmitter concentration and synaptic activity. Decreases in patient’s functional activities of daily living. Increased risk of postoperative cognitive dysfunction (POCD) and delirium. Increased sensitivity to anesthetic medications. Reduced autonomic abilities that influence a patients’ response to physiologic changes stresses, surgery, and anesthesia.
Peripheral nervous system	Peripheral nerve deterioration. Dysfunction of genes responsible for myelin sheath protein components. Decreased myelinated nerve fiber conduction velocity. Mild motor and sensory discriminatory changes of the feet. Changes in the senses (eg, pain, touch, and proprioception). Changes in autonomic nervous system.
Autonomic nervous system	Dysautonomia—sympathetic and cardiac vagal denervation, detrusor over activity, and delayed gastrointestinal motility. Symptomatic orthostasis.	Poor temperature regulation, blood pressure, and digestion. Poor sensitivity to heat and cold, decreased sweating, sialorrhea, and seborrhea. Sexual dysfunction. Early urinary incontinence or constipation, etc.