NIH Stroke Scale The Good, The Bad, and The Ugly

NIH Stroke ScaleThe Good, The Bad, and The Ugly

Press F5 for sound on the presentation1NIHSSLevel of consciousnessAlert 0 pointsDrowsy 1 pointStupor 2 pointsComa 3 points

Before exploring the good, the bad, and the ugly of the NIH stroke scale I will take a few minutes to review the scale. As opposed to other scoring systems, the NIH stroke scale renders higher scores for abnormalities noted. At the beginning of most neurologic examinations, one assesses the state of alertness of the patient. If the patient is fully alert, a score of zero is recorded. If the patient is comatose, a score of 3 is recorded.

2NIHSSQuestions Month/AgeAnswer both correctly 0 pointsAnswers one correctly1 pointNone are correct2 points

Next, the examiner asks the patient two questions, such as the patients age and orientation. If both questions are answered correctly, a score of zero is rendered.

3NIHSSResponse to 2 CommandsFollows 2 command correctly0 pointsFollows 1 command correctly1 pointCannot follow either command2 points

The patient is then asked to perform 2 simple tasks and the responses are recorded accordingly.

4NIHSSBest GazeNormal0 pointsPartial gaze to one side1 pointForced gaze to one side2 points

Ocular motility is then assessed. Full conjugate gaze, partial gaze paresis, or forced gaze to one side is recorded. This excludes the variety of possible ocular motility dysfunctions that can occur as a result of a brain stem infarction. While this assesses gaze dysfunction that can occur with a major middle cerebral infarction, this does not adequately assess ocular motility dysfunction that may occur as a result of a brainstem infarction.

5NIHSSVisual FieldsNo visual loss0 pointsPartial hemianopsia1 pointComplete hemianopsia 2 pointsBilateral visual loss3 points

A simple visual field examination by confrontation is then scored. This is a very important and integral part of the overall examination and may provide clues as to the potential prognosis. Unfortunately, many observers are not adept at performing this portion of the examination.

6NIHSSFacial Motor FunctionNo weakness 0 pointsMinor unilateral weakness 1 pointPartial unilateral weakness 2 pointsComplete uni or bilateral weakness 3 points

Facial weakness is assessed with a score of 0-3. This is an area in which there is occasional interrater variation.

7NIHSSUpper Extremity Motor Function(Right and Left Scored Independently)Normal0 pointsDrift1 pointSome effort against gravity2 pointsNo effort against gravity3 pointsNo movement4 points

Upper extremity gross strength is measured from 0 for normal function to a 4 for no movement at all. Each side is recorded independently.

8NIHSSLower Extremity Motor Function(Right and Left Scored Independently)Normal0 pointsDrift1 pointSome effort against gravity2 pointsNo effort against gravity3 pointsNo movement4 points

Lower extremity gross strength is similarly evaluated.

9NIHSSExtremity Ataxia(Cannot Be Tested in Presence of Paresis)No ataxia0 pointsAtaxia in 1 extremity1 pointAtaxia in 2 extremities2 points

Extremity ataxia is scored from 0-2. The explicit caveat is this is not to be evaluated if there is significant weakness. This represents a redundancy in the overall score and may lead to falsely excessively high total scores. Unfortunately many raters do not understand this caveat.

10NIHSSSensory LossNormal0 pointsMild to moderate loss1 pointSevere to total loss2 points

Sensation is scored from 0-2. It should be noted that higher cognitive sensory integration, especially that of localization or identity of body parts, is assessed separately.

11NIHSSLanguageNo aphasia0 pointsMild to moderate aphasia1 pointSevere aphasia2 pointsMute3 points

Speech and language function, independent from a disturbance of articulation, is assessed a score of 0 for normal speech and language to a 3 if the patient is mute.

12NIHSSArticulation (Dysarthia)Normal0 pointsMild to moderate1 pointSevere2 points

The mechanics of speech, or articulation, are assessed independently of the speech and language component. If articulation is normal, the patient is scored a 0. If the patient is severely dysarthric, the patient is scored a 2.

13NIHSSExtinction/InattentionNo abnormality0 pointsExtinction to one modality1 pointExtinction to 2 modalities2 points

Lastly, higher cognitive sensory integration in the form of extinction or inattention to localization of body parts is evaluated. This typically represents nondominant parietal lobe function which is to be contrasted with contralateral elements of speech and language function, which typically score much higher.

14The GoodReliableInterrater reliability confirmedValidTime efficientOriginal trial had a 6 minute averageCell phone with video capability takes 38 seconds longer than bedside examination

The NIH stroke scale was originally devised to quantify the severity of a stroke. It was used in the landmark NIH stroke study involving the use of TPA. The stroke scale was validated in that trial as well as subsequent other studies. On multiple occasions the interrater reliability has been confirmed. In the original trial, it took the average rater 6 minutes to complete the evaluation. In a more recent trial assessing the validity of cell phone video phonic evaluation of acute stroke, it took 38 seconds longer to do the evaluation via theremote approach as opposed to the bedside evaluation.

15The BadTendency to favor speech/language function over higher integrated sensory functionL MCA infarcts average 4 points higher than R MCA infarctsSome items represent redundancyAtaxia with gross motor functionDysarthria with aphasiaToo often ataxia is over represented

The NIH stroke scale has a tendency to favor speech and language function over higher integrated sensory function. On average, left middle cerebral infarctions score 4 points higher than do similar sized right middle cerebral infarctions. Some items in the NIH stroke scale represent redundancy. For instance, ataxia is superimposed upon weakness. The scale is intended to evaluate ataxia only in the absence of major weakness. Scoring mistakes tend to occur in the setting of weakness with perceived ataxia. Too often, ataxia is over represented in the rating score. The other major area of redundancy involves scoring of dysarthria as well as elements of an aphasia.

16The UglyBrainstem/cerebellar function overly minimizedNot a good scale for the dizzy plus patient

Brainstem and cerebellar function is minimally represented on the NIH stroke scale. A few items that can be related to brainstem function, such as gaze paresis, can arise from a cerebral infarction or posterior circulation. Posterior circulation infarctions may have a much worse outcome though the low NIH stroke scale might suggest. In the evaluation of the dizzy plus patient, it is certainly to the advantage of the physician making the determination of whether to administer intravenous TPA or not, to have visual observation of the examination of the patient, either at bedside or via telemedicine approach.

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