Overview
Clinical Meaning
Ageing alters the amount and quality of sensory information reaching the brain.
Ageing alters the amount and quality of sensory information reaching the brain. The change is usually gradual, but its effects can be substantial: an older adult may miss a medication label, fail to hear an alarm, misjudge a step, or appear inattentive during conversation. Vision commonly becomes less efficient at focusing on near objects, adapting to darkness, detecting contrast, and tolerating glare. A less flexible lens contributes to presbyopia, while changes in the pupil and other ocular structures reduce the light reaching the retina. These mechanisms explain why an older adult may need brighter, evenly distributed light for reading yet find direct glare uncomfortable. Age-related hearing loss, or presbycusis, typically develops slowly and affects higher-frequency sounds first. Speech may remain audible but less intelligible, especially when several people are speaking or background noise is present. The person may say “yes” without having understood the message, which can be mistaken for confusion or non-adherence. Smell and taste may diminish, and changes in touch or proprioception can reduce awareness of heat, pressure, or body position. Reduced sensory input can impair appetite, hazard...