We aim to hypothesize that patients with nystagmus, skew deviation, truncal ataxia and abnormal saccades have more strokes in the posterior circulation causing deficits that are not detectable on the NIHSS. Integration of these exam findings in our routine NIHSS assessment may help with early recognition of posterior circulation strokes and due to its reproducibility, will also be helpful in making acute treatment decisions.

Not all signs caused by stroke are captured as deficits on the NIHSS which is heavily weighted towards anterior circulation strokes. Signs on neurological examination including Nystagmus, Skew deviation, truncal ataxia, and abnormal saccades have high localizing value towards a posterior circulation stroke and are not routinely tested. 

19 patients with Nausea, vomiting and/or dizziness and with NIHSS <3 were enrolled from November 2020 to March 2021. They were assessed for Nystagmus, Skew deviation, truncal ataxia and abnormal Saccades with 1 point given to each if present. NIHSS-SAAD score was then re-calculated with the addition of these 4 exam findings and correlated with MRI brain for positive vs negative ischemic stroke with further characterization of the location of the stroke if positive. The two obtained NIHSS were then compared to assess if NIHSS-SAAD proved to be a better predictor of posterior circulation stroke. 

Although posterior circulation strokes account for a small part of all strokes, the diagnosis tends to be overlooked. Truncal ataxia, Abnormal Saccades, Skew deviation and Nystagmus are neurologic deficits that increase the likelihood of a posterior circulation stroke and which the NIHSS does not capture. The NIHSS should not substitute for a comprehensive neurologic examination.