A stroke is like a heart attack of the brain: blood flow to a brain part is disrupted. The blood supply can be affected either due to a block in the brain arteries (ischaemic stroke) or due to rupture of blood arteries in the brain (haemorrhagic stroke).
A stroke can happen in any brain region. The symptoms manifest differently depending on which area is affected.
Experts suggest that nine major brain regions can be affected by stroke. Each brain region has designated functions, and the severity of the stroke determines the symptoms and how the person recovers from it.
Stroke specialist Dr Harsha KJ of Dr Harsha’s Stroke Centre, Bengaluru, says, “The effects of a stroke vary from person to person, and every stroke is different, so recovery will be different.”
This listicle highlights nine types of strokes.
Frontal lobe stroke
“The frontal lobe is the front-most and one of the biggest regions in our brain that controls a wide variety of functions,” says Dr Priyank Vasavada, a neurosurgeon at M S Ramaiah Medical College and Hospital, Bengaluru.
The frontal lobe controls the functions of language, memory, problem-solving and judgement. It also plays a crucial role in emotional expression, personality and movement. The middle cerebral artery (the biggest blood vessel in the brain) supplies blood to different regions, including the frontal lobe. When this blood vessel gets blocked or ruptured, the frontal lobe’s motor cortex area gets affected.
The complications after a frontal-lobe stroke again depend on which side of the front lobe is affected. “If the left side is affected, the person will have speech and behavioural problems. If the right side is affected, the person will have movement and swallowing problems,” adds Dr Vasavada.
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Parietal lobe stroke
The parietal lobe is located at the top of the middle area of the brain. It is also home to the brain’s primary sensory region. In this area, the brain integrates sensory signals from touch, smell, vision and taste. “Also, the parietal lobe plays a crucial role in navigation function,” says Dr Vasavada.
A stroke in this region shows sensory deficits like loss of taste or touch. A parietal lobe stroke goes unnoticed unless a severe sensory symptom is noticed. Speech problems can also be seen in the affected person due to the involvement of the interior parietal lobe.
Temporal lobe stroke
“The temporal lobe is mainly responsible for auditory processing functions, acquiring and retaining memory and understanding language,” says Dr Vasavada. This region also has significant structures called the hippocampus, which is involved in memory, and the amygdala, which is involved in emotion He adds that if this region is affected by a stroke, the person will have memory, behavioural, and hearing problems.
Occipital lobe stroke
This region is present at the back of the skull and right above the hollow at the back of the head. It is a visual processing region of the brain responsible for visuospatial processing, distance and depth perception, colour determination, recognition of object and face, and memory formation.
If this region is affected during a stroke, the person will have problems such as loss of central vision, cortical blindness, partial blindness, visual hallucinations, besides difficulty in recognising faces.
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Brain stem stroke
The brain stem is a junction between the brain and the spinal cord. It consists of the midbrain, pons and the medulla oblongata. “It has its own nucleus [control centre] and controls multiple things such as vision, respiration, heart rate, blood pressure and some of the chemical balances in the body,” says Dr Vasavada.
Complications from a brain stem stroke again depend on the area affected by this regional stroke. Problems such as one-sided facial weakness, paralysis, respiratory distress and visual disturbance are associated with this stroke, he says.
Cerebellar stroke
The cerebellum, a significant structure of the hindbrain, is located at the back of the brain near the brain stem. It primarily involves coordination, movement and balance functions. Stroke in this region affects the coordination and movement of the body, thus causing ataxia, cerebellar cognitive affective syndrome and an impaired memory.
Thalamic stroke
Dr Vasavada says, “[The thalamus] is also known as a centre of all sensory information which goes to the brain.” Any sensation that we feel in our body, be it pain, temperature, pressure, vibration, hearing or vision, but except smell, is processed in the thalamus. Apart from that, the thalamus also has some role in speech.
The classical sign of a thalamic stroke is the sensory deficit on the opposite side of the body. If a person has a right-sided stroke, the left side of the body will lose sensation, explains Dr Vasavada.
Basal ganglia stroke
This core area of the brain controls coordinated movements. Dr Vasavada explains that whatever we learn over a period of time — for example, driving, writing or playing a musical instrument — is because of the basal ganglia processing the learning smoothly.
The basal ganglia are a motor relay centre. Most of our functions are muscle-related work. If a person gets this stroke, Dr Vasavada says the movement becomes gross and sketchy (i.e. uncoordinated). The person may experience tremors, involuntary movements and distorted speech.
Internal capsule stroke
The white matter structure of the brain is a bundle of nerve fibres from different brain parts, especially the motor area, explains Dr Vasavada. If a person has a stroke in this area, the complications will be severe as the area connects with all the brain regions through the nerves. He says the person might have sensory loss, cognitive impairment, memory loss, facial weakness, movement disorders and vision problems.
