About dementia

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About the brain

Changes in a person's behaviour can be a sign of damage to certain areas of the brain.

Visit our interactive Brain Tour to see how the brain works and how it is affected by Alzheimer’s.

Below are descriptions of what each area of the brain does and how damage to that area can cause specific changes.

Brain areas

Limbic System

  • Affected early in Alzheimer's disease
  • Involved with memory and emotion
  • Links the lobes of the brain, enabling them to connect behaviour with memories
  • Controls emotion and basic needs (such as sleeping and eating)

Changes that may be seen:

  • Difficulty in finding objects and remembering where they were placed
  • Suspiciousness
  • Irritability, depression or anxiety

Hippocampus and temporal lobes

  • Hippocampus: where verbal and visual memory are processed (verbal memories are words - memories related to what we read or say or hear; visual memory lets us recognize objects, faces and places to guide us around our environment)
  • Temporal lobes: controls new learning and short-term memory

Changes that may be seen:

  • Inability to retain memory of the recent past
  • Living in the present moment
  • Loss of vocabulary
  • Inability to recognize familiar faces, objects or places

Parietal lobes

  • Put activities in a sequence (such as putting clothes on in the right order, using tools or performing tasks that require a logical sequence, such as starting and driving a car)
  • Control our ability to understand spatial information (such as where we are in a specific environment, and where other objects are)

Changes that may be seen:

The problems will vary depending on whether the left or right side of the brain is affected.

  • Using words incorrectly
  • Difficulty in understanding what others say
  • Speaking in general terms rather than specifically
  • Inability to express thoughts clearly in writing
  • Difficulty handling bank accounts or paying bills
  • Getting lost easily
  • Difficulty putting on clothing
  • Balance and gait difficulties

Frontal lobe

  • Initiates activity, and lets us plan and organize our actions
  • Regulates our social judgment and behaviour (such as knowing what behaviour is appropriate to a situation, interpreting the feelings of other people and monitoring our own actions)

Changes that may be seen:

  • The person appears apathetic, uninterested
  • Stops hobbies or other activities previously enjoyed
  • Quickly loses interest in an activity, seems content to sit, does not respond to others
  • Withdraws from others
  • Is unable to stop an activity, repeating it over and over

Occipital lobe

  • Controls vision, and the ability to see and combine colours, shapes, angles and movement into meaningful patterns

Changes that may be seen:

Although the occipital lobe is not usually directly involved in Alzheimer's disease, the surrounding visual areas that allow us to put the elements of vision together can be affected, which leads to unusual perceptual difficulties, such as loss of depth vision or inability to see movement.


Last Updated: 11/13/14
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