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NIHSS Scale

Neurological assessment for acute stroke

Medical Specialty:
neurology

FOR PROFESSIONAL USE ONLY

This calculator is a support tool intended exclusively for health professionals. It does not replace clinical judgment. The final decision regarding diagnosis and treatment is the sole responsibility of the professional.

Patient Data

Level of Consciousness: The investigator must choose a response even if a full assessment is impaired by obstacles such as an orotracheal tube, language barriers, trauma, or orotracheal dressing. A 3 is given only if the patient makes no movement (other than reflex posturing) in response to painful stimulation.
Questions: The patient is asked about the month and their age. The answer must be correct – there is no partial credit for being close. Patients with aphasia or stupor who do not understand the questions will receive a 2. Patients unable to speak due to orotracheal intubation, orotracheal trauma, severe dysarthria of any cause, language barriers, or any other problem not secondary to aphasia will receive a 1. It is important that only the initial response is considered and that the examiner does not “help” the patient with verbal or non-verbal cues.
Commands: The patient is asked to open and close their eyes and then open and close their non-paretic hand. Substitute with another single-step command if the hands cannot be used. Credit is given if an unequivocal attempt is made but not completed due to weakness. If the patient does not respond to the command, the task should be demonstrated to them (pantomime) and the result recorded (i.e., follows one, none, or both commands). Patients with trauma, amputation, or other physical impairment should be given compatible single commands. Only the first attempt is recorded.
Best Gaze: Only horizontal eye movements are tested. Voluntary or reflex (oculocephalic) eye movements are scored, but caloric testing is not used. If the patient has a conjugate gaze deviation, which can be overcome by voluntary or reflex activity, the score will be 1. If the patient has an isolated peripheral nerve palsy (CN III, IV, or VI), score 1. Gaze is tested in all aphasic patients. Patients with eye trauma, dressings, pre-existing blindness, or other disorder of visual acuity or field should be tested with reflex movements and the choice made by the investigator. Establishing eye contact and then moving close to the patient from side to side can clarify the presence of gaze palsy.
Visual: Visual fields (upper and lower quadrants) are tested by confrontation, using finger counting or visual threat, as appropriate. The patient should be encouraged, but if they look to the side of the finger movement, it should be considered normal. If there is unilateral blindness or enucleation, the visual fields in the remaining eye are assessed. Score 1 only if a clear asymmetry, including quadrantanopia, is found. If the patient is blind for any reason, score 3. Double simultaneous stimulation is performed at this time. If there is an extinction, the patient receives 1 and the results are used to answer question 11.
Facial Palsy: Ask or use pantomime to encourage the patient to show their teeth or smile and close their eyes. Consider the symmetry of facial contraction in response to a painful stimulus in a poorly responsive or uncomprehending patient. In the presence of facial trauma/dressing, orotracheal tube, tape, or other physical barrier that obscures the face, these should be removed as much as possible.
Motor Arm Left: The arm is placed in the appropriate position: arms extended (palms down) at 90° (if sitting) or 45° (if supine). Drift is scored if the arm falls before 10 seconds. The aphasic patient is encouraged by voice and pantomime, but not with painful stimulation. Each limb is tested individually, starting with the non-paretic arm. Only in case of amputation or joint fusion in the shoulder, the item should be considered not testable (NT), and an explanation should be written for this choice.
Motor Arm Right: The arm is placed in the appropriate position: arms extended (palms down) at 90° (if sitting) or 45° (if supine). Drift is scored if the arm falls before 10 seconds. The aphasic patient is encouraged by voice and pantomime, but not with painful stimulation. Each limb is tested individually, starting with the non-paretic arm. Only in case of amputation or joint fusion in the shoulder, the item should be considered not testable (NT), and an explanation should be written for this choice.
Motor Leg Left: The leg is placed in the appropriate position: held at 30° (always in the supine position). Drift is scored if the leg falls before 5 seconds. The aphasic patient is encouraged by voice and pantomime, but not with painful stimulation. Each limb is tested individually, starting with the non-paretic leg. Only in case of amputation or hip joint fusion, the item should be considered not testable (NT), and an explanation must be written for this choice.
Motor Leg Right: The leg is placed in the appropriate position: held at 30° (always in the supine position). Drift is scored if the leg falls before 5 seconds. The aphasic patient is encouraged by voice and pantomime, but not with painful stimulation. Each limb is tested individually, starting with the non-paretic leg. Only in case of amputation or hip joint fusion, the item should be considered not testable (NT), and an explanation must be written for this choice.
Limb Ataxia: This item aims to find evidence of a unilateral cerebellar lesion. Test with eyes open. In case of visual defect, ensure testing is done in the intact visual field. Finger-nose and heel-shin tests are performed on both sides, and ataxia is scored only if it is out of proportion to weakness. Ataxia is absent in a patient who cannot understand or is hemiplegic. Only in case of amputation or joint fusion, the item should be considered not testable (NT), and an explanation should be written for this choice. In case of blindness, test by touching the nose from an extended arm position.
Sensory: Assess sensation or facial grimace to pinprick or withdrawal from noxious stimulus in the obtunded or aphasic patient. Only sensory loss attributed to stroke is scored as abnormal and the examiner should test as many body areas (arms [not hands], legs, trunk, face) as needed to accurately check for a hemisensory loss. A score of 2, 'severe or total,' should only be given when a severe or total loss of sensation can be clearly demonstrated. Therefore, patients in stupor and aphasic patients will likely score 1 or 0. The patient with a brainstem stroke who has bilateral sensory loss receives a 2. If the patient does not respond and is quadriplegic, score 2. Patients in a coma (item 1a=3) are arbitrarily given a 2 on this item.
Best Language: A great deal of information about comprehension can be obtained during the preceding sections of the exam. The patient is asked to describe what is happening in the attached picture, to name the items on the attached naming list, and to read from the attached sentence list. Comprehension is judged from these responses as well as from all commands in the preceding general neurological exam. If visual loss interferes with the tests, ask the patient to identify objects placed in their hand, repeat and produce speech. The intubated patient should be encouraged to write. The patient in a coma (Item 1a=3) will automatically receive a 3 on this item. The examiner must choose a score for patients in stupor or who are uncooperative, but a score of 3 should be reserved for the patient who is mute and does not follow any single command.
Dysarthria: If the patient is thought to be normal, a more adequate assessment is obtained by asking the patient to read or repeat words from the attached list. If the patient has severe aphasia, the clarity of articulation of spontaneous speech can be rated. Only if the patient is intubated or has other physical barriers to speech production, should this item be considered not testable (NT). Do not tell the patient why they are being tested.
Extinction and Inattention: Sufficient information to identify neglect may have been obtained during the previous tests. If the patient has severe visual loss, which prevents the test of double simultaneous visual stimulation, and the cutaneous stimuli are normal, the score is normal. If the patient has aphasia but appears to attend to both sides, the score is normal. The presence of visual spatial neglect or anosognosia may also be considered as evidence of neglect. Since the abnormality is only scored if present, the item is never considered not testable.

About this Calculator 💡

The National Institutes of Health Stroke Scale (NIHSS) is a standardized, objective clinical tool that has become a gold standard in emergency and urgent care services for quantifying the severity of neurological deficits in patients who have suffered a Stroke (AVC), particularly the ischemic type, which is the most common. Although initially developed for research purposes, its application is now fundamental for the rapid and precise assessment of the degree of brain injury. The scale consists of 11 items that evaluate crucial neurological areas such as level of consciousness, visual function, limb motor strength, sensation, and language and speech functions. Each of these items receives a score of 0, indicating normalcy, up to a maximum value that varies according to the severity of the detected alteration. The total NIHSS score is the sum of the values of each item, ranging from 0 to 42. The final score is of paramount importance for clinical decision-making, as the higher the score, the greater the severity of the stroke; for example, scores between 1 and 4 generally indicate a mild stroke, while scores above 21 signal a severe stroke. This score directly guides the patient's eligibility for acute treatments, such as thrombolysis, which requires rapid action. Furthermore, the NIHSS is used to monitor the patient's progress over time, document the therapy's effectiveness, and ensure objective and uniform communication among medical teams, making it an indispensable tool in the modern and agile management of stroke.

Reference Values

  • •0: No neurological deficit
  • •1-4: Minor deficit
  • •5-15: Moderate deficit
  • •16-20: Moderate to severe deficit
  • •21-42: Severe deficit

Formula

Calculation Methodology The NIHSS score is calculated by summing 11 individual neurological exam items (level of consciousness, eye movements, visual fields, facial palsy, motor strength, ataxia, sensory, language, dysarthria, and neglect), with scores ranging from 0 to 42.

Reference

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