NIHSS scores in ischemic small vessel disease: a study in CADASIL

Area of Science:

• Neurology
• Neuroscience
• Vascular Neurology

Background:

• The National Institutes of Health Stroke Scale (NIHSS) is a standard tool for assessing neurological deficits in acute ischemic stroke.
• Its utility in chronic stages and specific conditions like cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a model for ischemic small vessel disease, remains unevaluated.
• Evaluating the NIHSS in CADASIL is crucial for understanding its limitations in diffuse small vessel diseases.

Purpose of the Study:

• To investigate the correlation between the NIHSS score and clinical severity in a large cohort of patients with CADASIL.
• To determine the effectiveness of the NIHSS in reflecting neurological deficits and disability in this specific patient population.
• To identify potential limitations of the NIHSS in assessing chronic and diffuse small vessel disease.

Main Methods:

• Analysis of demographic and clinical data from 220 patients with MRI-confirmed lacunar infarcts within a prospective cohort.
• Neurological assessment using the NIHSS and modified Rankin Scale (mRS) to evaluate clinical severity.
• Statistical analysis including calculation of predictive values for NIHSS thresholds and general linear models to assess relationships between NIHSS, cognitive function (MMSE), gait, and disability (mRS), controlling for confounders.

Main Results:

• Only 7.3% of patients had an NIHSS >5, while 20.5% presented with significant disability (mRS ≥3).
• NIHSS ≤5 showed high positive predictive value (85.3%) for minimal disability but low specificity (33.3%).
• NIHSS, MMSE score, and gait disturbances were strong independent predictors of disability, accounting for 73% of mRS variance, compared to NIHSS alone (50%). Patients with NIHSS ≤5 and mRS ≥3 had lower MMSE scores or gait disturbances.

Conclusions:

• The NIHSS is insufficient for accurately reflecting neurological deficits and clinical severity in patients with lacunar infarctions due to chronic and diffuse small vessel disease like CADASIL.
• A more comprehensive neurological scale is required for evaluating ischemic cerebral microangiopathy.
• This scale should incorporate assessments of cognitive function and gait disturbances alongside traditional neurological measures.