Sensory Disturbance

The sensory nervous system is one of the most complex functions of the human body. We normally take it for granted, so any malfunction can be particularly disturbing. Sensory disturbance can result in a sensation, for example burning, without any apparent cause.

Sensory abnormalities can arise from anywhere – from the cortex of the brain to the fine nerve endings in the tip of the toes. They may be caused by the entrapment of a nerve due to prolonged posture or tissue thickening, such as carpal tunnel, or by a medical condition such as diabetes which damages the nerve fibres, giving rise to a diminished or unpleasant sensation. Temporary sensory changes can also occur during migraine or hyperventilation.

The sensory nervous system is a complex yet a highly organised network. Most sensory abnormalities can be diagnosed, given sufficient expert knowledge of the distribution of particular sensory function and of the diseases that could afflict them.

Investigation of sensory nerve abnormalities usually involves neurophysiological tests, such as nerve conduction studies where electrical stimuli are applied to individual nerves and the amplitude and speed of conduction is then measured. Electromyography is another option, whereby small needles are inserted into particular muscles to detect alterations in electrical activity and the resulting loss of nerve supply. Whilst these tests may sound unpleasant, in the correct hands they merely feel a little uncomfortable or simply strange.

Ultimately, sensation is part of normal human experience and for many people, unusual sensations arrise not from any physical abnormality but rather from a psychological shift in perception.