National Institutes of Health Stroke Scale

While administering the NIHSS, it is important that the examiner does not coach or help with the assigned task. The examiner may demonstrate the commands to patients that are unable to comprehend verbal instructions; however, the score should reflect the patient's own ability. It is acceptable for the examiner to physically help the patient get into position to begin the test, but the examiner must not provide further assistance while the patient is attempting to complete the task. For each item, the examiner should score the patient's first effort, and repeated attempts should not affect the patient's score. An exception to this rule exist in the language assessment (Item 9), in which the patient's best effort should be scored. 1. Level of consciousness (LOC) Level of consciousness (LOC) testing is divided into three sections. The first LOC items test for the patient's responsiveness. The second LOC item is based on the patient's ability to answer questions that are verbally presented by the examiner. The final LOC sub-section is based on the patient's ability to follow verbal commands to perform simple task. Although this item is broken into three parts, each sub-section is added to the final score as if it is its own item. Notes • If patient is unable to follow the command to track an object, the investigator can make eye contact with the patient and then move side to side. The patient's gaze palsy can then be assessed by their ability to maintain eye contact. • If patient is unable to follow any commands, assess the horizontal eye movement via the oculocephalic maneuver. This is done by manually turning the patient's head from midline to one side and assessing the eye's reflex to return to a midline position. • If the patient has isolated peripheral nerve paresis assign a score of 1. 3. Visual field test Assess the patient's vision in each visual fields. Each eye is tested individually, by covering one eye and then the other. Each upper and lower quadrant is tested by asking the patient to indicate how many fingers the investigator is presenting in each quadrant. The investigator should instruct the patient to maintain eye contact throughout this test, and not allow the patient to realign focus towards each stimulus. With the first eye covered, place a random number of fingers in each quadrant and ask the patient how many fingers are being presented. Repeat this testing for the opposite eye. Notes • If the patient is unable to understand verbal commands, the instructions should be demonstrated to the patient. • Patients incapable of comprehending any commands may be tested by applying a noxious stimulus and observing for any paralysis in the resulting grimace. 5. Motor arm With palm facing downwards, have the patient extend one arm 90 degrees out in front if the patient is sitting, and 45 degrees out in front if the patient is lying down. If necessary, help the patient get into the correct position. As soon as the patient's arm is in position the investigator should begin verbally counting down from 10 while simultaneously counting down on their fingers in full view of the patient. Observe to detect any downward arm drift prior to the end of the 10 seconds. Downward movement that occurs directly after the investigator places the patient's arm in position should not be considered downward drift. Repeat this test for the opposite arm. This item should be scored for the right and left arm individually, denoted as item 5a and 5b. To perform this item the patient is asked to read from the list of words provided with the stroke scale while the examiner observes the patient's articulation and clarity of speech. Notes • Default coma score:2 • An intubated patient should not be rated on this item, instead make note of the situation in the scoring documents. 11. Extinction and inattention (f.k.a. neglect) Sufficient information regarding this item may have been obtained by the examiner in items 1–10 to properly score the patient. However, if any ambiguity exist the examiner should test this item via a technique referred to as "double simultaneous stimulation". Double simultaneous stimulation is performed by having the patient close their eyes and asking them to identify the side on which they are being touched by the examiner. During this time, the examiner is alternating between touching the patient on the right and left side. Next, the examiner touches the patient on both sides at the same time. This should be repeated on the patients face, arms, and legs. To test extinction in vision, the examiner should hold up one finger in front of each of the patient's eyes and ask the patient to determine which finger is wiggling or if both are wiggling. The examiner should then alternate between wiggling each finger and wiggling both fingers at the same time. Notes • Default coma score: 2 • Patient with severe vision loss that correctly identifies all other stimulations scores a 0 ==Usage==

The NIHSS was designed to be a standardized and repeatable assessment of stroke patients utilized by large multi-center clinical trials. Clinical researchers have widely accepted this scale due to its high scoring consistency, which has been demonstrated in inter-examiner and in test-retest scenarios. Clinical research use of the NIHSS typically involves obtaining a baseline NIHSS score as soon as possible after onset of stroke symptoms The NIHSS is then repeated at regular intervals or after significant changes in patient condition. This history of scores can then be utilized to monitor the effectiveness of treatment methods and quantify a patient's improvement or decline. The NIHSS has also been used in a prospective observational study, to predict 3 month outcomes of patients with undernutrition during hospital stays directly after a stroke. NIHSS use in tPA eligibility NIHSS has gained popularity as a clinical tool utilized in treatment planning. Tissue plasminogen activator (tPA), a type of thrombolysis, is one of the main options for treatment of acute ischemic strokes (the type of stroke caused by blood clots that are preventing blood flow within a cerebral artery). The effectiveness and risk of tPA is strongly correlated with the delay between stroke onset and tPA delivery ("door-to-needle time"). Current standards recommend for tPA to be delivered within 4,5 hours of onset, while best results occur when treatment is delivered within 90 minutes of onset. Since the NIHSS has been established as a quick and consistent quantifier of stroke severity, many physicians have looked to NIHSS scores as indicators for tPA treatment. This rapid assessment of stroke severity is targeted to reduce delay of tPA treatment. While some clinical trials have used minimum and maximum NIHSS scores to determine eligibility for acute treatment such as tPA, NIHSS structure In an effort to produce a complete neurological assessment the NIHSS was developed after extensive research and multiple iterations. The goal of the NIHSS was to accurately measure holistic neurological function by individually testing specific abilities. NIHSS total score is based on the summation of 4 factors. These factors are left and right motor function and left and right cortical function. The NIHSS assesses each of these specific functions by the stroke scale item listed in the chart below. Modified National Institutes of Health Stroke Scale (mNIHSS) The Modified NIH Stroke Scale (mNIHSS) is a shortened, validated version of the mNIHSS. It has been shown to be equally, if not more, accurate than the longer, older NIHSS. It removes questions 1A, 4, and 7. This makes the mNIHSS shorter and easier to use. The mNIHSS predicts patients at high risk of hemorrhage if given tissue plasminogen activator (tPA) and which patients are likely to have good clinical outcomes. The mNIHSS has also recently been shown to be taken without seeing the patient, and only using medical records. This potentially improves care while in the emergency room and the hospital, but also facilitates retrospective research. == Accuracy==

The National Institutes of Health Stroke Scale has been repeatedly validated as a tool for assessing stroke severity and as an excellent predictor for patient outcomes. Severity of a stroke is heavily correlated with the volume of brain affected by the stroke; strokes affecting larger portions of the brain tend to have more detrimental effects. NIHSS scores have been found to be reliable predictors of damaged brain volume, with a smaller NIHSS score indicating a smaller lesion volume. Effect of stroke location on NIHSS prediction of stroke severity The NIHSS places 7 of the possible 42 points on abilities that require verbal skills; 2 points from the LOC questions, 2 points from LOC commands, and 3 points from the Language item. The NIHSS only awards 2 points for extinction and inattention. Approximately 98% of humans have verbal processing take place in the left hemisphere, indicating that the NIHSS places more value on deficits in the left hemisphere. This results in lesions receiving a higher (worse) score when occurring in the left hemisphere, compared to lesions of equal size in the right hemisphere. Due to this emphasis, the NIHSS is a better predictor of lesion volume in the strokes occurring within the left cerebral hemisphere. However, correlation between functional recovery and NIHSS scores was weaker when the stroke was isolated to the cortex. ==Other stroke-related scores==

• ABCD² score • CHADS2 score == References ==