Symptoms of a Parietal Lobe Stroke

A parietal lobe stroke is a type of stroke that occurs in the parietal lobe at the top of the middle area of the brain. The type and severity of parietal stroke symptoms are based largely on the location and size of the injury, but can include impairment of speech, thought, coordination, and movement.

Like all strokes, a parietal lobe stroke involves either the rupture or blockage of a blood vessel in the brain. It's the resulting lack of constant blood flow to the parietal lobe that deprives that area of adequate oxygen and causes cell death that impairs many sensory, visual, and/or language functions—sometimes permanently.

Common Symptoms

Where a stroke injury occurs—and how it impacts other parts of the brain—will ultimately determine the type and extent of symptoms experienced.

For most people, the left hemisphere of the parietal lobe is the language center of the brain, while the right hemisphere is responsible for cognition, calculation, and spatial orientation. Broadly speaking, the symptoms of a parietal lobe stroke are defined by which hemisphere is affected.

With a right-sided parietal lobe stroke, there may be:

• Left-sided weakness
• Abnormal sensations (paresthesia) on the left side of the body
• Inability to see out of the lower left quadrant of each eye (inferior quadrantanopia)
• Spatial disorientation, including problems with depth perception and navigating front and back or up and down
• Inability to recognize objects to the left side of a space (hemiagnosia)
• Inability to recognize the left side of one's own body (referred to by some as "alien hand syndrome")
• Loss of proprioception (the ability to know where your body is oriented in your surroundings), causing misjudgment in movement and balance
• Lack of awareness or concern about the left-sided impairment (hemispatial neglect)
• Impulsive, manic, or inappropriate behaviors

With a left-sided parietal lobe stroke, there may be:

• Right-sided weakness
• Paresthesia on the right side of the body
• Inability to see out of the lower right quadrant of each eye
• Difficulty with speech or language comprehension (aphasia)
• Problems with simple mathematics
• Impaired ability to read, write, and learn new information
• Lack of awareness that a stroke had even occurred (anosognosia)
• Cautious or hesitant behaviors

Both right- and left-sided parietal lobe strokes may also result in:

• Depression
• Memory problems
• Chronic fatigue
• Astereognosis, a sensory disorder in which you are unable to identify an object by touch. It typically occurs if the back end of the parietal lobe is damaged.

Rare Symptoms

It is not uncommon for a stroke injury in the parietal lobe to extend to parts of the brain, such as the frontal lobe, temporal lobe (situated beneath the parietal lobe), or occipital lobe (situated toward the back of the cerebral cortex). It may also involve the brainstem and cerebellum.

In such cases, the symptoms of a parietal stroke may be accompanied by "classic" stroke symptoms, such as facial drooping or arm or leg paralysis.

However, if the stroke injury is isolated in the parietal lobe, facial drooping and paralysis are far less common. While there may be arm or leg weakness, people with a parietal stroke don't usually experience a total loss of limb function.

Gerstmann Syndrome

There are uncommon conditions in which sensory disorders develop in clusters. One such example is Gerstmann syndrome, a rare disorder characterized by the impairment of four specific neurological functions:

• Inability to write (agraphia)
• Loss of the ability to do math (acalculia)
• Inability to identify fingers (finger agnosia)
• Inability to differentiate between the right and left side of the body (right-left disorientation)

Gerstmann syndrome is caused by damage or impaired blood flow to the upper sides of the parietal lobe but may also be the result of multiple sclerosis or a brain tumor.

Apraxia

In some cases, a parietal lobe stroke can interfere with executive function (the ability to think abstractly and make decisions based on analysis and learned behaviors). Although executive function is believed to be carried out by prefrontal areas of the frontal lobe, it is the parietal lobe that feeds sensory information to that part of the brain.

When the transmission of these signals is blocked by a stroke injury, it can interfere with how the brain "plans" movement, resulting in a condition known as motor apraxia (the inability to perform movements on command).

Other variations include ideomotor apraxia (inability to mimic a performed gesture), constructional apraxia (inability to copy a drawing), and eye-opening apraxia (inability to open one's eyes on command).

Complications

The impact of a parietal lobe stroke can often significant in the elderly, who may already be struggling with cognitive, sensory, and movement problems.

One common complication seen in older individuals with a parietal lobe stroke is delirium (an abrupt change in the brain that causes confused thinking and reduced awareness of one's surroundings).

When a parietal lobe stroke occurs in the right hemisphere, the loss of recognition of the left side of the world can be extremely confusing and contribute to the loss of organized thought. Without the means to compensate for these sensory impairments, a person may become increasingly confused, inattentive, and disjointed in their thinking.

Outcomes and Expectations

The complications of a parietal stroke can vary based on the types and severity of symptoms involved.

However, unlike a frontal lobe stroke where limb paralysis is common, the loss of sensory function in a parietal lobe stroke usually allows for speedier recovery of motor skills under the care of a physical therapist and occupational therapist.

Speech and language impairment can be more difficult to overcome and typically requires ongoing and intensive speech therapy. Studies suggest that at least 90 hours of speech therapy may be needed to overcome aphasia and that anything less than 44 hours will likely be non-beneficial.

Arguably, the greatest challenge is overcoming issues like hemispatial neglect or anosognosia, in which the stroke survivor is not even aware of their impairment.

In such instances, people are less likely to participate in rehab or may unknowingly place themselves in harm's way. Unless there is a coordinated intervention by a partner, loved one, or legal guardian, recovery can be difficult.

When to See a Doctor

Recognizing the symptoms of a stroke can save your life or that of someone else. The American Stroke Association offers an easy-to-remember mnemonic (FAST) to help you know when it's time to call for help.

FAST stands for:

• Facial drooping
• Arm weakness (particularly if it occurs on one side)
• Speech difficulties (including slurring)
• Time to call emergency services

If the first three were to occur, then you know it's time to do the fourth and call 911. If you're in doubt, take no chances and call for emergency services.