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Brain & Nervous System

Introduction

  • As people age, the number of nerve cells in the brain decreases. Brain weight decreases by 20% by age 90, selective nerve cells loss of between 5 and 50% and cells tend to shrink. Because of these changes, the brain may function slightly less well. Older people may react and do tasks somewhat more slowly. However, significant deterioration in brain function is not part of normal ageing.

Sign & Symptoms

  • Some mental functions may be subtly reduced. They include vocabulary, short-term memory, the ability to learn new material, and the ability to recall words.
  • After about age 60, the number of cells in the spinal cord begins to decrease. As a result, older people may notice a decrease in sensation.
  • As people age, nerves may conduct signals more slowly. Reaction time tends to decline with age but often not significantly until about the age of 75. Usually, this change is so minimal that people do not notice it.
  • Also, the nervous system’s response to injury is reduced. Nerves may repair themselves more slowly and incompletely in older people than in younger people. Therefore, older people are more vulnerable to injury.

Disease

  • All these changes are more pronounced in Alzheimer’s diseases.
  • In nerve disorders, the sense of touch (sensation) may be abnormal or lost. Or, weakness or paralysis may occur.
  • Some nerve disorders cause pain or other unusual, often unpleasant sensations.
  • Two terms commonly used to describe nerve disorders are neuralgia and neuropathy.
  • Neuralgia refers to pain that does not necessarily involve damage to nerves.
  • Neuropathy refers to nerve damage that does not necessarily cause pain. A neuropathy may cause pain, abnormal sensations, loss of sensation, weakness, or a combination of these symptoms. Less commonly, a neuropathy affects body functions, such as blood pressure or sweating.
Last Reviewed : 26 April 2012
Writer : Dr. Ho Bee Kiau
Reviewed : Dr. Cheah Wee Kooi