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.
[3] Scores for this item are assigned by a medical practitioner based on the stimuli required to arouse patient.
This item is tested because conjugated eye deviation (CED) is present in approximately 20% of stroke cases.
CED is more common in right hemispheric strokes and typically in lesions affecting the basal ganglia and temporoparietal cortex.
Damage to these areas can result in decreased spatial attention and reduced control of eye movements.
While inspecting the symmetry of each facial expression the examiner should first instruct patient to show his or her teeth (or gums).
[3] Notes This test for the presence of a unilateral cerebellar lesion, and distinguishes a difference between general weakness and incoordination.
After completing items 1-8, it is likely the investigator has gained an approximation of the patient's language skills; however, it is important to confirm this measurement at this time.
These brain regions are vital in coordinating motor control of the tongue, throat, lips, and lungs.
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 his or her eyes and asking him or her to identify the side on which they are being touched by the examiner.
[3] Notes The NIHSS was designed to be a standardized and repeatable assessment of stroke patients utilized by large multi-center clinical trials.
[8] 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.
This history of scores can then be utilized to monitor the effectiveness of treatment methods and quantify a patient's improvement or decline.
[12][13] 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.
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).
[16] 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,[10][11] guidelines such as those from the American Heart Association / American Stroke Association urge against NIHSS scores being used as the sole reason for declaring a patient as ineligible for tPA treatment.
[17] 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.
Due to this emphasis, the NIHSS is a better predictor of lesion volume in the strokes occurring within the left cerebral hemisphere.
On average, an increase of 1 point in a patient's NIHSS score decreases the likelihood of an excellent outcome by 17%.