NIH Stroke Scale Exam Demonstration | Neurology

NIH Stroke Scale evaluates 11 functions with score 0-42: Level of consciousness, motor function, visual fields, facial appearance, ataxia, sensory function, language, neglect. Used pre, intra, and post-treatment. Neuroimaging options: CT scan (most available, rules out hemorrhage); Cerebral angiography (shows vessels and occlusion level); MRI with diffusion-weighted imaging. Primary goal is ruling out hemorrhage.

Emergency stroke evaluation requires rapid assessment including precise symptom onset time determination and NIHSS scoring within 5 minutes. Non-contrast CT is the essential first-line imaging to exclude hemorrhage before thrombolytic administration. CT angiography identifies large-vessel occlusions amenable to thrombectomy. Mismatch imaging using diffusion-weighted MRI and perfusion studies identifies salvageable penumbral tissue. The penumbra concept underlies reperfusion therapy goals - restoring blood flow to viable but endangered tissue before irreversible damage occurs.

NIHSS is the gold standard for stroke assessment with 11 items scored 0-42. ABCD2 score predicts 48-hour recurrence risk: Age ≥60, BP ≥140/90, Clinical deficit, Duration, Diabetes. CT is first-line for hemorrhage exclusion; MRI with diffusion is more sensitive. CT signs include hyperdense artery sign, insular ribbon sign, and loss of gray-white differentiation. MRI identifies penumbra for treatment planning.

CT head is the gold standard for initial stroke diagnosis. Approximately 25% of MRIs in hyperacute posterior circulation strokes may be negative. NIHSS (National Institutes of Health Stroke Scale) is a 15-point scale assessing stroke severity and predicting treatment outcomes. NIHSS >10 suggests possible large vessel occlusion. mRS (Modified Rankin Scale) is a 6-point scale assessing functional disability: 0=no disability, 1-2=mild, 3-4=moderate, 5-6=severe, 7-8=bedridden, 9-10=death. ASPECTS (Alberta Stroke Program Early CT Score) evaluates 10 regions of the middle cerebral artery territory on CT, scoring from 0-10. Lower scores indicate more extensive early ischemic changes.

NIHSS scores may reflect the size of the ischemic penumbra (salvageable brain tissue), with higher scores in early presentation potentially indicating larger penumbra and greater treatment potential. However, NIHSS alone cannot distinguish between infarcted and salvageable tissue, which requires imaging evaluation. NIHSS scores have different clinical significance at different time points—early scores may reflect salvageable tissue while later scores may reflect established infarction. The same NIHSS score at different time points may have different implications for treatment decisions and prognosis. NIHSS scores alone cannot determine stroke mechanism (thrombotic vs. embolic) or identify large vessel occlusion. Large vessel occlusion requires imaging evaluation (CT angiography or MR angiography) for definitive diagnosis. NIHSS may suggest significant neurological deficit but cannot identify specific vascular pathology. Comprehensive stroke evaluation requires additional diagnostic testing beyond NIHSS scoring. NIHSS scores have limitations in treatment decision-making—a patient with NIHSS score of 10 who deteriorates after treatment may have established infarction that cannot be salvaged.

The NIHSS has significant limitations for individual patient assessment: it is poorly designed for posterior circulation strokes, may underestimate severity in these cases, and has significant outliers (same score, different infarct volumes). It should not be used in isolation for treatment decisions. The NIHSS is most useful for clinical trials and research, not for individual patient management. Algorithms have been developed to facilitate NIHSS administration by organizing items to minimize contradictory responses and reduce assessment time.

NIHSS has limitations requiring clinical judgment: (1) Pain-related inability to move should be scored as weakness (3) rather than assuming neurological cause; (2) NIHSS correlates better with MCA strokes than posterior circulation strokes, which often present with lower scores due to limited contribution from ataxia and visual fields; (3) Cortical weakness mimics lower motor neuron weakness due to shared hypotonia—omega sign helps distinguish; (4) NIHSS >6 correlates with large vessel occlusion likelihood, but some LVO patients have low scores; (5) Non-English speakers require adapted assessments (counting, local pictures). Junior clinicians commonly overestimate normalcy and underestimate subtle deficits, requiring deliberate practice to overcome expectation bias. Effective strategies for mastering NIHSS: practice on all suspected stroke patients, use waiting periods for assessment, integrate into routine workflow without delaying interventions, and consider training paramedics and stroke nurses to expand capacity for rapid assessment.

NIHSS (National Institutes of Health Stroke Scale) is a standardized neurological assessment scale used to quantify stroke severity, developed in the late 1980s to prioritize inter-rater reliability over diagnostic specificity. It evaluates 11 neurological functions across 15 domains, with scores ranging from 0 (no abnormalities) to 42 (most severe). Key clinical thresholds include: scores ≤5 indicate mild stroke with 80% home return probability, 6-13 suggest rehabilitation hospital care, and ≥14 often require long-term care facility placement. NIHSS scores guide treatment decisions: tPA thrombolytic therapy is typically applied for scores 6-25, while mechanical thrombectomy requires NIHSS ≥6 for anterior circulation and ≥10 for posterior circulation. Important limitations include floor effect (score 0 may miss significant abnormalities), posterior circulation bias (underestimates symptoms like vertigo), and left hemisphere bias (language items favor left hemisphere strokes). The simplified sNIHSS provides rapid assessment using 6 key domains for time-constrained situations.

Posterior circulation strokes (vertebrobasilar system) produce vertigo, ataxia, diplopia, and cranial nerve deficits. Cerebellar strokes produce ataxia, dysmetria, dysdiadochokinesia, and truncal ataxia. Stroke must be differentiated from subdural hematoma, meningitis/encephalitis, hypertensive encephalopathy, brain tumors, seizures (Todd's paralysis), and metabolic disorders. The NIH Stroke Scale (NIHSS) is a standardized 11-item assessment tool evaluating consciousness, gaze, visual fields, facial palsy, motor function, ataxia, sensory, language, dysarthria, and extinction/attention. Scores range from 0 (no deficit) to 42 (severe deficit). The SAMU assessment (smile, arm, speech) provides rapid pre-hospital stroke identification.

The second part addresses 10 specific post-stroke deficits requiring comprehensive rehabilitation. Key recommendations include: (1) Early, continuous, repeated assessment across domains; (2) Bilateral upper limb training for motor function improvement; (3) Trunk constraint therapy to reduce compensatory movements; (4) Shoulder orthoses for subluxation management; (5) Extracorporeal shock wave therapy for shoulder pain and CRPS; (6) Task-oriented exercise programs for lower limb mobility; (7) Aquatic and aerobic exercises (3 sessions/week, 8+ weeks) for walking speed and balance; (8) Oral hygiene education and dental referral; (9) Elimination function management with TENS for urinary incontinence; (10) Behavioral programs for bowel function.

Stroke rehabilitation requires a comprehensive, multidisciplinary approach combining cognitive exercises, physical therapy, and psychological support to help patients recover motor functions, language, and memory through personalized, progressive training programs that build confidence and autonomy.

Stroke care requires multidisciplinary teams: speech and language therapists for swallowing/communication, physiotherapists for mobility/fall prevention, consultants/nurses/doctors for medical management, and orthopedic surgeons for complications. Physiotherapy includes walking frame training, fall prevention, pressure sore prevention, and joint mobility maintenance.

Nurses serve as gatekeepers for identifying invisible cognitive and visual perceptual deficits that physicians often miss. Best practices require OT assessment within 48 hours of stroke admission. The NIHSS (15-item scale) evaluates neurological function, with scores above 6 indicating need for inpatient rehab. However, standardized assessments alone are insufficient—functional tasks reveal subtle deficits. During ambulation, patients may collide with objects on one side or ignore staff. Meal trays show untouched food on one side. Patients may brush only one side of teeth, shave only one cheek, or dress only one side. Even simple tasks like brushing teeth involve multiple cognitive-perceptual components: spatial relations, motor planning, task sequencing, visual discrimination, and initiation. These observations guide appropriate referrals and interventions.

Post-stroke rehabilitation is a comprehensive, multidisciplinary approach involving doctors, nurses, physiotherapists, occupational therapists, speech-language pathologists, neuropsychologists, social workers, dieticians, and physical education teachers who work together to stimulate recovery, help patients adapt to lasting effects, and prevent complications through personalized therapy programs that include physical mobility training, speech and swallowing exercises, cognitive rehabilitation, and home environment adaptations.