Effects of Stroke
The human brain is divided into regions. Each region controls different movements, senses, or intellectual functions. Therefore, the effects of a stroke depend on which region of the brain is damaged. Fatigue will be an effect of any stroke, and different types of stroke can also cause similar damage.
Effects of Left Hemisphere Strokes
Because the left side of the brain controls motor and sensory functions of the right side of the body, a stroke on the left side of the brain affects the right side of the body. The following effects may happen, depending on which area of the left side of the brain has been damaged (the common medical terms used are also provided):
- Paralysis or loss of strength in right side of body (hemiparesis)
- Loss of feeling in right side of body (hemianaesthesia)
- Loss of field of vision to the right affecting both eyes (hemianopia)
- Difficulty speaking eg can’t name objects or express thoughts (dysphasia)
- Not understanding what others are saying (dysphasia).
Other effects of left hemispheric strokes may include
- Inability to read and/or write
- Slurred monotonous speech (dysarthria)
- Difficulty swallowing or eating (dysphagia)
- Loss of awareness to the right and even ignoring the right side
- Thoughts tend to be disconnected
- Memory loss for spoken things
- Difficulty with performing purposeful movement (eg combing the hair)
- Confusion between left and right
- Easily frustrated
- Slowness, clumsiness
- Overwhelming urges to perform or repeat some actions
- Difficulty structuring and planning behaviour
- Poor motivation
- Difficulty dealing with numbers (arithmetic).
Effects of Right Hemisphere Strokes
The right side of the brain controls motor and sensory functions for the left side of the body. The following may happen depending on which area of the right side of the brain has been damaged (the common medical terms used are also provided):
- Paralysis or loss of strength in left side of body (hemiparesis)
- Loss of feeling in left side of body (hemianaesthesia)
- Loss of awareness to the left and even ignoring the left side
- Loss of field of vision to the left, affecting both eyes (hemianopia).
Other effects of right hemispheric strokes may include:
- Excessive talking
- Slurred monotonous speech (dysarthria)
- Difficulty swallowing or eating (dysphagia)
- Difficulty recognising familiar faces
- Difficulty seeing how things relate to each other in space
- Difficulty interpreting sounds
- Loss of insight and denying existence of problems
- Depression
- Tendency to sarcasm, or uncharacteristic and at times embarrassing behaviour or comments
- Short attention span
- Memory problems
- Poor judgement of physical abilities (especially safety awareness)
- Muddled sense of time
- Difficulty with abstract thinking (eg comparing ideas, solving problems)
- Mood swings
- Lack of interest, difficulty in ‘getting going’
- Acting without thinking
- Difficulty in recognising someone else’s mood.
Effects of brainstem and cerebellar strokes
Brainstem Strokes
Brainstem strokes tend to be quite serious. The brainstem is the part of the brain that connects with the top of the spinal cord. It acts as the conduit for all of the nerves that connect the brain above with the spinal cord below, and also the cerebellum (see below). It also contains special nerve cells that keep us awake, control breathing, heart rate and blood pressure, facial and eye movement and sensation, hearing, smell, taste, swallowing, tongue movement, and the muscles of the neck.
Possible effects of brainstem stroke include
- Coma, pronounced drowsiness or disturbed alertness
- Breathing problems
- Spontaneous changes in heart rate and blood pressure
- Nausea and vomiting
- Loss of movement and/or sensation in one or both sides of the body
- Double vision, because one eye cannot move in unison with the other
- Loss of sensation in one eye, or one side of the face, or tongue
- An enlarged or dilated pupil
- Slurred speech
- Loss of movement on one side of the face
- Problems with swallowing
- Incoordination or abnormal jerky movements when trying to do something.
Cerebellar strokes
The cerebellum is situated under the cerebral hemisphere, and behind the brainstem. Its major function is to control and co-ordinate movement and balance. When a stroke happens in the cerebellum, the following may occur:
- Loss of balance (ataxia). The person may ‘seem drunk’. They walk with the feet more widely apart, and weave or wobble. Alcohol will make this worse because it also interferes with cerebellar function
- Slurred and monotonous speech (dysarthria)
- Clumsiness and/or shaking limb (inco-ordination) when the person tries to do something (eg drink a cup of tea or pick up an object). If the stroke is only affecting one side of the cerebellum, the abnormality will be on the same side as the stroke
- Abnormal eye movement, the eyes have a quick/slow flicker as they move (nystagmus)
- Abnormal movement patterns of the head and upper body
Because the brain’s nerve connections with the cerebellum can be damaged in other types of stroke, some of the abnormalities seen in cerebellar strokes may also occur in brainstem or even cerebral strokes.
Stroke Foundation of N.Z. Inc (National office)
P O Box 12482
L1, Federation House
95-99 Molesworth Street
WELLINGTON
Tel: 04 472 8099
0800 STROKE (0800 78 76 53)
E-mail: strokenz@stroke.org.nz
© 2007 New Zealand Stroke Foundation Inc. All Rights Reserved.