The National Institutes of Health Stroke Scale (NIHSS) is a standardized, 11-item tool used to measure the severity of a stroke. The scale ranges from 0 to 42, with higher scores indicating a more severe neurological deficit. Accurate scoring guides treatment decisions and monitors a patient’s condition over time. The primary challenge occurs when a patient is intubated, as the breathing tube prevents all verbal testing. This mechanical barrier necessitates specific, standardized modifications to ensure the resulting score reliably measures stroke-related brain function.
NIHSS Components Scored Normally
Many parts of the NIHSS can be assessed using the standard protocol because they rely on physical movement and response to sensory input rather than verbal output. The Motor Assessment items for the arms and legs (Items 5 and 6) remain fully testable by asking the patient to hold their limbs against gravity. The examiner watches for any drift or inability to lift the limb, scoring the deficit based on the patient’s physical performance.
Limb Ataxia (Item 7), which tests for coordination, is scored normally using the finger-to-nose or heel-to-shin test. The Sensory item (Item 8) is tested using a pinprick to compare sensation on both sides of the body. The intubated status does not interfere with the patient’s ability to perceive or react to these stimuli.
Adapting the Assessment of Consciousness and Gaze
Evaluating the Level of Consciousness (LOC) involves three sub-items: 1a (Alertness), 1b (Questions), and 1c (Commands). Alertness (1a) is assessed by observing the patient’s spontaneous behavior or response to stimulation, which is the same for all patients. If the patient is not spontaneously alert, noxious stimuli, such as a sternal rub or a painful squeeze, may be used to elicit a response and determine the degree of arousal.
The LOC Questions item (1b), which normally asks for the patient’s age and the current month, is directly affected by intubation. The established rule requires assigning a score of 1 to patients who are unable to speak due to the endotracheal tube but are otherwise awake and responsive. This score acknowledges the mechanical barrier and prevents an inaccurate score that would imply lack of comprehension due to brain injury.
For LOC Commands (1c), the examiner must rely entirely on non-verbal compliance. The patient is typically asked to open and close their eyes and then grip and release the non-paretic hand. If the patient can perform these two actions, they score normally; if not, the command should be demonstrated through pantomime to ensure the patient understands the request.
Assessment of Best Gaze (Item 2) is adapted because the patient cannot follow a finger on verbal command. The examiner must establish eye contact and move their face or an object side to side to see if the patient’s eyes track the target horizontally. If the patient is unresponsive, the oculocephalic reflex, or “doll’s eye maneuver,” may be used to assess reflexive eye movement. This involves gently turning the patient’s head to see if their eyes move conjugately in the opposite direction, providing information about brainstem function.
Scoring Speech and Communication
The assessment of Best Language (Item 9) requires significant modification because standard verbal output is impossible. To test for aphasia, the examiner must use alternative methods of communication. The intubated patient should be asked to write their name or a simple sentence, if physically able.
If writing is not possible, language comprehension and expression are assessed through non-verbal responses to written commands or picture-based recognition. For example, the patient may be asked to point to specific objects or pictures in response to a written question or command. The score for Item 9 is determined by the patient’s ability to communicate and comprehend using these alternative means.
Dysarthria (Item 10) refers to slurring of speech caused by motor issues, which is impossible to assess when a patient is intubated. Best Language (Item 9) is a measure of aphasia, the central language processing problem, and can still be tested non-verbally.
Documentation Rules and Clinical Interpretation
Because certain components cannot be fully tested due to the endotracheal tube, specific documentation is necessary to maintain the integrity of the scale. Item 10 (Dysarthria) is mechanically untestable, and the accepted procedure is to mark this item as “Untestable” (UT) or assign a score of 9, with the specific reason noted in the chart. This documentation must explicitly state that the item is untestable “due to intubation” to prevent misinterpretation of the patient’s neurological status.
The use of “Untestable” scores means the total NIHSS score will be lower than the maximum possible, potentially skewing comparisons of stroke severity. Clinical interpretation must account for the modified score, making the change in score over time the more meaningful measure of improvement or decline. Consistency across all healthcare providers is required to ensure serial scores are comparable and reliable for monitoring the patient’s neurological trajectory.