National Institute of Health Stroke Scale is used to assess the severity in ischemic stroke. it is very useful for stroke physicians for treatment and follow-up.

1. National Institutes of Health Stroke Scale (NIHSS):
Why and How?
Dr. Md. Saiduzzaman Munna
Medical Officer
Department of Neurology
Mymensingh Medical College Hospital
Mymensingh, Bangladesh.

2. Background
 It is a systematic assessment tool designed to measure the neurological deficits
in acute ischemic stroke.
 First developed in 1989 as 15 item scale.
 Modified NIHSS consisting 5/8/11 domains have been developed.

3. Advantages of NIHSS
Widely used, valid, reliable tool to assess stroke severity.
Low inter-personal variability.
Easy, less time consuming (even non-neurologists and nurses can
perform).
Few instruments needed (Only a pin to assess sensation).
Well matches with arteries involved.
Used to predict stroke outcome.
Used to include or exclude patients from IV thrombolysis
candidate.

4. Domains of NIHSS
1. Level of consciousness:
a) Responsiveness-
0- Alert,
1- Not alert but arousable by minor stimulation,
2- Not alert but requires repeated/strong painful stimulation for
movement,
3- Respond only with reflex motor / autonomic effects or totally
unresponsive.

5. Domains of NIHSS………
b) Questions: current month and age.
0- Answers both correctly
1- Answers one question correctly
2- Answers neither correctly.
c) Commands: Ask to open and close eyes and grip and release nonparetic hand.
0- performs both correctly.
1- performs one task correctly.
2- performs neither task correctly.

6. Domains of NIHSS………
2. Best Gaze: Test horizontal eye movement.
0- Normal.
1- Partial gaze palsy (Abnormal in one or both sides)
2- Forced deviation or total gaze paresis.
3. Visual: Visual field.
0- No visual loss.
1- Partial hemianopia.
2- Complete hemianopia.
3- Bitemporal hemianopia including cortical blindness.

7. Domains of NIHSS………
4. Facial palsy: asked to show their teeth or raise their eyebrows and close their
eyes.
0- Normal symmetrical movement.
1- Minor paralysis (asymmetry on smiling)
2- Partial paralysis (lower face).
3- Complete paralysis (both upper and lower face).

8. Domains of NIHSS………
5. Motor arm:
a) Motor arm left- Arm is extended (palms up) 90 degrees (if sitting) or 45 degrees
(if supine). Drift is scored if the arm falls before 10 seconds.
0- No drift.
1- Drifts before 10 seconds.
2- Some effort against gravity.
3- No effort against gravity.
4- No movement.
b) Motor arm right- same as a.

9. Domains of NIHSS………
6. Motor leg: Leg is raised at 30 degrees (supine). Drift is scored if the leg falls
before 5 seconds.
a) Motor leg left-
0- No drift.
1- Drifts within 5 seconds.
2. Some effort against gravity.
3- No effort against gravity.
4- No movement.
b) Motor leg right- same as a.

10. Domains of NIHSS………
7. Limb ataxia: Perform finger-nose and heel-shin test.
0- Absent/Patient paralyzed/cannot understand or amputation or joint fusion.
1- present in one limb.
2- Present in both limbs.
8. Sensory: If level of consciousness is impaired, score if a grimace or an
asymmetric withdrawal is observed.
0- No sensory loss.
1- Mild to moderate sensory loss.
2- Total sensory loss.

11. Domains of NIHSS………
9. Best language: Have the patient describe a picture/ surrounding.
0- Normal.
1- Mild to moderate aphasia.
2- Severe aphasia.
3- Global aphasia.

12. Domains of NIHSS………
10. Dysarthria: Patient is asked to read or repeat words from a list.
0- Normal or unable to test.
1- Mild to moderate dysarthria (Can be understood with some difficulty)
2- Severe dysarthria.

13. Domains of NIHSS………
11. Extinction and inattention (Neglect)
0- No abnormality.
1- Inattention or extinction to one of the sensory modalities (Visual, tactile,
auditory, spatial).
2- Profound hemi-inattention or extinction to more than one modality.

14. Interpretation
NIHSS Score Severity
< 5 Mild impairment
5-14 Moderate
15-25 Moderate to Severe
> 25 Very Severe
Range: 0-42

15. NIHSS in IV thrombolysis
IV thrombolysis is indicated if NIHSS is between
4-22

16. Calculation
Of
NIHSS