Dulled, unpleasant, or otherwise altered sensations in the absence of an obvious stimulus. Numbness and pins-and-needles are common abnormal sensations. The special senses can be impaired by damage to the relevant sensory apparatus (see vision, disorders of; smell; deafness; tinnitus). Other causes of abnormal sensation include peripheral nerve damage caused by diabetes mellitus, herpes zoster infection, or pressure from a tumour, and disruption of nerve pathways in the brain or spinal cord due to spinal injury, head injury, stroke, and multiple sclerosis. Pressure on or damage to nerves can sometimes be relieved by surgery or by treatments for the cause. In other cases, distressing abnormal sensation can be relieved only by cutting the relevant nerve fibres or by giving injections to block the transmission of signals.
Sensation, abnormal |
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