Ageing and the Special Senses

Original Editor - User Name

Top Contributors - Lucinda hampton, Kim Jackson, Simisola Ajeyalemi, Rucha Gadgil, Tolulope Adeniji and Aminat Abolade  

Introduction

The special senses are the senses that have specialized organs devoted to them. Special senses include the following:

• Hearing (the ear)
• Sight/Vision (the eye)
• Smell (the nose)
• Taste (the tongue)

As we grow older, most people notice that eg the volume needs turning up a little on the television, or a brighter light is needed when reading. This is due to the well documented fact that over the years the special senses tend to become blunted

Changes to the Sensory System

• Touch - Shows a decrease in tactile sensitivity affecting proprioception. So, treat them in their bare feet to increase input, or alter the shape of their foot to increase base – you may need special orthoses to maintain alignment.

• Eyes - Loss of orbital fat with sunken eye appearance and lid laxity. Lipid deposits in cornea, reduced tears and dry cornea. Lens elasticity loss plus degenerative changes in muscles of the eye affect lens contraction. Visual fields and colour detection alter, and floating objects become more common. Accommodation to sudden changes in light decreases; an increased dependency on sight for balance develops. If applicable, check spectacles are clean and that the patient is wearing the correct pair, e.g. not their reading glasses when walking, and ensure the treatment area is well lit. Instruction leaflets and exercise sheets should be in large, bold type.

• Ears - Degeneration of hair cells and neurones in cochlea and temporal cortex. Impaired elasticity affects vibration of basilar membrane. There can be excessive wax accumulation. Degeneration of hair cells in semicircular canals affects reflex postural control, with uncertainty and unreliability to move in darkness. Middle ear ossification impairs tone sensitivity, perception of background noise and sound localisation.

• Nose - Atrophic changes in the mucosae with impaired sense of smell. 60% of 70–80 year olds have impaired smell. With decreased taste, this affects appetite. Energy systems are low affecting tolerance and fatigue. Undetected toxic fumes can poison the body.

• Taste - Atrophic changes in throat mucosae and neuronal degeneration with taste buds reduced 64% by the age of 75. Diminished reflex to cough and swallowing as well as a decrease in salivary secretion.

Treatment

Confusional states can be caused by sensory deprivation or communication may be affected. It is important to talk more slowly and clearly than loudly. Check hearing aids are working correctly, and keep a communicator at hand, but be ready to use written communication methods or basic sign language. If repetition of a sentence is necessary, initially do not change the order of the words you used; it may be that person may not have heard you fully, rather than because they have misunderstood what you have said.

Resources

Ageing and the Central Nervous System: Special Senses