What are lateralizing signs in cerebrovascular accident (CVA) or stroke?

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Last updated: February 10, 2025 • View editorial policy

From the Guidelines

Lateralizing signs in cerebrovascular accident (CVA) or stroke are symptoms and signs that indicate the location of the brain lesion.

Lateralizing Signs

These signs can help determine the vascular distribution of the ischemic lesion and include:

  • Left-sided weakness, paresthesia, or sensory loss due to ischemia or infarction in the distribution of the right internal carotid artery or middle cerebral artery 1
  • Right-sided weakness, paresthesia, or sensory loss due to ischemia or infarction in the distribution of the left internal carotid artery or middle cerebral artery 1
  • Aphasia as a sign of ischemia or infarction in the distribution of the left internal carotid artery or middle cerebral artery, or in ambidextrous or left-handed individuals, the right internal carotid artery 1
  • Monocular blindness affecting one eye due to ischemia or infarction in the distribution of the internal carotid artery or middle cerebral artery on the same side 1
  • Homonymous hemianopsia (visual loss that involves one half of the visual field) due to ischemia or infarction in the distribution of the internal carotid artery or middle cerebral artery on the same side 1
  • Ataxia, cranial nerve deficits, visual field loss, dizziness, imbalance, and incoordination due to ischemia or infarction in the vertebrobasilar system 1 These lateralizing signs are crucial in the diagnosis and management of stroke, as they can help identify the location and type of stroke, and guide treatment decisions 2, 3.

From the Research

Lateralizing Signs in Cerebrovascular Accident (CVA) or Stroke

Lateralizing signs in cerebrovascular accident (CVA) or stroke refer to the symptoms and signs that indicate the location of the brain damage. These signs can help healthcare professionals determine which hemisphere of the brain is affected by the stroke.

Hemispheric Lateralization

  • Hemispheric lateralization can influence functional and cardiovascular outcomes after stroke, but the evidence is not well established 4.
  • Studies have shown that there is no difference in functional outcome between patients with right or left hemisphere stroke 4.
  • However, right-sided patients with large hemisphere infarctions (LHI) had higher frequency of atrial fibrillation and cardio-embolism, and higher incidence rates of malignant brain edema and cardiovascular events during hospitalization 5.

Motor Lateralization

  • Motor lateralization provides a foundation for predicting and treating non-paretic arm motor deficits in stroke 6.
  • The bilateral hemispheric model of motor control has successfully predicted hemisphere-specific motor control and motor learning deficits in the ipsilesional arm of patients with unilateral stroke 6.
  • Motor performance deficits in the non-paretic arm of stroke patients vary with both the side of the lesion and the severity of contralesional impairment 6.

Neurological Clinical Manifestation

  • The symptoms that follow a stroke depend on the area of the brain that has been affected and the amount of tissue damaged 7.
  • Parameters for predicting long-term outcome in stroke patients have not been clearly delineated, but studies have identified certain neurological symptoms and signs that can aid in management and predict outcomes 7.
  • Dilated pupils, agitation, acute onset headache, lower Glasgow Coma Scale (GCS) score, seizure, and eye gaze impairment had significantly higher prevalence in hemorrhagic stroke patients, while gradual progressive headache is significantly higher in ischemic stroke patients 7.

Action Observation and Hemispheric Dominance

  • Action observation is lateralized to the dominant hemisphere, rather than the ipsilesional hemisphere, which may reflect an interaction between the lesioned hemisphere and the dominant hemisphere in driving lateralization of brain activity after stroke 8.
  • Individuals with right hemisphere stroke showed greater activity in the dominant left hemisphere, rather than the ipsilesional right hemisphere, during action observation 8.

References

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.