What is the importance of a thorough sensory examination in a patient who has experienced a cerebrovascular accident (CVA)?

Sensory Examination in Cerebrovascular Accident

A thorough sensory examination is critical in CVA patients because sensory deficits are among the most common neurological impairments after stroke, affecting tactile sensation, proprioception, and visual-spatial processing, and these deficits directly impact functional recovery, safety, and rehabilitation outcomes. 1

Why Sensory Assessment is Essential

Prevalence and Impact of Sensory Deficits

• Tactile deficits are the most common form of sensory impairment after stroke, with substantial but variable recovery occurring in the months following CVA, particularly for proprioception 1
• Sensory impairments encompass multiple modalities including tactile sensation, pain, temperature, pressure, vibration, proprioception, stereognosis, and graphesthesia 1
• Visual field loss affects approximately 30% of stroke survivors, making it the most common visual impairment after CVA 1
• Vision plays a central role in many human functions, so visual field deficits can profoundly affect quality of life, motivation, social behaviors, and the ability to perform daily activities 1

Clinical Significance for Risk Stratification

• Hemibody sensory loss is a key feature that identifies patients at HIGH risk for recurrent stroke when presenting within 48 hours of symptom onset 1
• Patients with purely sensory symptoms (numbness, pain, or paresthesia) require consideration of alternative diagnoses including radiculopathy, neuropathy, microvascular cerebral or spinal pathology, or lacunar stroke 1
• Atypical sensory symptoms such as patchy numbness and tingling are generally considered less urgent and may be seen by stroke specialists as required rather than emergently 1

Standardized Assessment Approach

Required Sensory Testing Components

The American Academy of Neurology recommends the following structured approach 2:

• Grade sensory deficits as: no sensory loss, mild sensory loss, or severe sensory loss 2
• Test for extinction or inattention (grade as absent, mild loss in 1 sensory modality, or severe loss in 2 modalities) 2
• Assess visual attention and visual field testing as part of the core sensory examination 2
• Comprehensive sensory testing should focus on multiple modalities, including vision, visual fields, and visual attention 2

NIH Stroke Scale Integration

• The NIH Stroke Scale is the gold standard for quantifying neurological deficits in acute stroke settings, with scores ranging from 0-42 points across 11 domains 2
• Perform NIHSS at defined intervals: immediately post-intervention, 24 hours, 72 hours, 7-10 days, 30 days, and 90 days 2
• A critical limitation: NIHSS may underestimate posterior circulation strokes as it lacks assessment of vertigo and dysphagia 2

Impact on Functional Outcomes and Rehabilitation

Motor-Sensory Integration

• Accurate evaluation of deficits in the patient's sensory and motor systems is paramount in establishing realistic rehabilitation goals 3
• Visual scanning deficits can result in inefficient acquisition of information about the environment and interfere with independent performance of many daily activities 4
• Deficits in visual scanning speed, identification of visual stimuli in the hemifield on the involved side, and use of systematic scanning patterns have been identified in hemiplegic patients 4

Cognitive and Perceptual Considerations

• The presence of scanning deficits may significantly interfere with performance on tests measuring higher level visual-perceptual skills such as visual closure, figure-ground perception, and visual memory 4
• An accurate assessment of visual-perceptual skills cannot be made without prior evaluation of basic oculomotor functions like scanning 4
• Patients with visual-spatial deficits after right CVA require specific visual-spatial rehabilitation 5

Critical Pitfalls to Avoid

Common Assessment Errors

• Do not rely solely on confrontation methods for visual field assessment—automated perimetry methods are more sensitive and precise and should be preferred when clarity is important, such as evaluation for driving 1
• Assessment of sensory deficits remains largely a matter of bedside examination, though sensory scales are under study and new devices can quantify deficits 1
• An accurate assessment of visual-perceptual skills cannot be made without prior evaluation of basic oculomotor functions such as scanning—this developmental framework is traditionally not applied in visual-perceptual evaluation but should be 4

Timing and Recovery Considerations

• Maximum spontaneous recovery of visual fields occurs in variable timeframes, with reports ranging from the first 2-10 days, the first month, or the first 3 months 1
• The percentage of patients achieving significant visual field recovery is uncertain, with estimates ranging from 7% to 85%, and the degree of recovery is highly variable 1
• Patients show substantial but variable somatosensory recovery in the months after stroke, especially for proprioception 1

Rehabilitation Implications

Targeted Interventions

• Patients with progressive CVA should be assessed for cognitive deficits and provided with appropriate cognitive retraining for attention deficits, visual neglect, memory deficits, and executive function difficulties 5
• Training to develop compensatory strategies for memory deficits is beneficial for patients with mild short-term memory impairments 5
• Multiple cognitive retraining approaches involving various disciplines may benefit patients with multiple areas of cognitive impairment 5

Specific Sensory Rehabilitation

• Interventions to restore or compensate for visual field deficits include explorative saccade training, prisms, visual restoration therapy (VRT), and transcranial direct current stimulation (tDCS) 6
• Although ocular motility problems can be corrected with surgery, vision and perception deficits are more difficult to overcome 6
• VRT makes use of neuroplasticity, which has shown efficacy in animal models but remains controversial in human studies 6