National Institutes of Health Stroke Scale (NIHSS)

Purpose of the measure

The NIHSS is a 15-item impairment scale, intended to evaluate
neurologic outcome and degree of recovery for patients with stroke. The
scale assesses level of consciousness, extraocular movements, visual
fields, facial muscle function, extremity strength, sensory function,
coordination (ataxia), language (aphasia), speech (dysarthria), and
hemi-inattention (neglect) (Lyden, Lu, & Jackson, 1999; Lyden, Lu,
& Levine, 2001). The NIHSS was designed to assess differences in
interventions in clinical trials, although its use is increasing in
patient care as an initial assessment tool and in planning postacute
care disposition (Schlegel et al., 2003; Schlegel, Tanne, Demchuk,
Levine, & Kasner, 2004).

Available versions

Original version. Brott, Adams, Olinger, Marler, Barsan,
Biller, Spilker, Holleran, Eberle, Hertzberg, Rorick, Moomaw, and Walker
(1989).

Features of the measure

Items:
Items of the NIHSS are based on three previously used
scales, the Toronto Stroke Scale, the Oxbury Initial Severity Scale and
the Cincinnati Stroke Scale (Brott et al., 1989).

The scale has 15 items in total which assess the following:

1. Level of consciousness

  • Responsiveness of the patient (rated from 0 – 3).
  • Questions: Patients are asked to state the month and their age
    (rated from 0 – 2).
  • Commands: The patient is asked to open and close the eyes and then
    to grip and release the non-paretic hand (hand not affected by partial
    motor paralysis) (rated from 0 – 2).

2. Best gaze

  • Horizontal eye movements of patient (rated from 0 – 2).

3. Visual

  • To assess the presence of hemianopia (rated from 0 – 3).

4. Facial palsy

  • Patients are asked to show their teeth or raise their eyebrows and
    close their eyes. Look for symmetry (rated from 0 – 3).

5. Motor arm

  • Left arm: Arm is extended (palms
    down) 90 degrees (if sitting) or 45 degrees (if supine). Drift is scored
    if the arm falls before 10 seconds (rated from 0 – 4, or UN if
    amputation or joint fusion).
  • Right arm: Same as in a.

6. Motor leg

  • Left leg: Leg is raised at 30 degrees (supine). Drift is scored if
    the leg falls before 5 seconds (rated from 0 – 4, or UN if amputation or joint fusion).
  • Right leg: Same as in a.

7. Limb ataxia

  • Finger-to-nose and heel-to-shin test (rated from 0 – 2, or UN if
    amputation or joint fusion)
    .

8. Sensory function

  • Pinprick. If level of consciousness is impaired, score if a grimace
    or an asymmetric withdrawal is observed (rated from 0 – 2).

9. Best language (aphasia)

  • Standard pictures are named (rated from 0 – 3).

10. Dysarthria

  • Patient is asked to read or repeat words from a list (rated from 0 – 2, or UN if intubated or other physical barrier).

11. Extinction and inattention (formerly called neglect)

  • Sufficient information to detect neglect may be obtained from prior
    testing (rated from 0 – 2).

An additional item that measures distal motor function has been used
in a few drug trials, but is not widely used in ongoing research or in
clinical practice.

Time:
The examination requires less than 10 minutes to
complete.

Scoring:
Each item is scored from 0 – 2, 0 – 3, or 0 – 4, and
untestable items are scored as “UN”. A score of 0 indicates normal
performance.

Total scores on the NIHSS range from 0 – 42, with higher values
reflecting more severe cerebral infarcts. Stroke severity is further
stratified in the following way:

(Source: Brott et al., 1989)

? 25 Very severe neurological impairment
5-14 Mild to adequately severe neurological impairment
< 5 Mild impairment

The predictive value of the scale can also aid in planning a
patient’s rehabilitation or long-term care needs, even as early as the
day of admission. NIHSS scores can be interpreted in the following way:

(Source: Schlegel et al., 2003; Rundek et al., 2000; Goldstein &
Samsa, 1997; DeGraba, Hallenbeck, Pettigrew, Dutha, & Kelly, 1999)

? 14 Severe: Long-term care in nursing facility required
6-13 adequate: Acute inpatient rehabilitation required
? 5 Mild: 80% with this score are discharged home

The NIHSS can be completed and scored automatically at the following
link:

http://sitemaker.umich.edu/chant/yale_nihss_calculator

Equipment:
none
typically reported.

Subscales:
The subscale items encompass level of
consciousness, vision, extraocular movements, facial palsy, limb
strength, ataxia, sensation, and speech and language.

Training:
A trained observer
rates the patent’s ability to answer questions and perform activities.
Training is minimal and is available through instructional videos: a
45-minute training program tape, and two certification tapes (Lyden et
al., 1994), or alternatively one can be trained and certified online at
the following website: http://www.nihstrokescale.org/
A new training DVD is now available and has established reliability
(Lyden et al., 2005).

It is important to note that one must be both trained and certified
in order to administer the NIHSS.

As the NIHSS was designed as an observational scale, measurement by
self-report or by telephone is not possible. However, measurement by
video telemedicine appears to be reliable and could offer a method for
remote assessment (Meyer et al., 2005; Shafqat, Kvedar, Guanci, Chang,
& Schwamm, 1999). This method of administration would require
slightly more time to complete.

To see video clips of the NIHSS items being administered by
telemedicine, visit the following link: https://telestroke.massgeneral.org/about.asp

Schmülling, Grond, Rudolf, and Kiencke (1998) examined whether the
NIHSS could be reliably administered without any formal training
program. The results of this study suggest that good inter-rater
reliability of the NIHSS depends on adequate training of the raters.
Inter-rater reliability among untrained raters was only poor (kappa =
0.33).

Alternative forms of NIHSS
  • 11-item modified NIHSS (mNIHSS).
    Developed by deleting poorly reproducible or redundant items (level of consciousness, face weakness, ataxia, and dysarthria) and collapsing the sensory item from 3 into 2 responses (Lyden, Lu, Levine, Brott, & Broderick, 2001). The mNIHSS consists of ten items with excellent reliability and one item with adequate reliability (Meyer, Hemmen, Jackson, & Lyden, 2002). The total score
    for the mNIHSS is 31.
  • 5-item NIHSS (sNIHSS-5) and 8-item NIHSS (sNIHSS-8).
    For
    pre-hospital assessment of stroke severity, an 8-item and a 5-item NIHSS
    have undergone preliminary evaluation. The 8 items that were most
    predictive of “good outcome” three months after stroke were: right leg,
    left leg, gaze, visual fields, language, level of consciousness, facial
    palsy, and dysarthria. The sNIHSS-8 comprises all 8 of these items and
    the sNIHSS-5 contains only the first 5. In the validation models,
    receiver operator characteristic’s (ROC) for the sNIHSS-8 and sNIHSS-5
    were adequate (ROC = 0.77 and 0.76, respectively). Furthermore, no
    significant difference between the sNIHSS-8 and the sNIHSS-5 was
    observed. The sNIHSS-5 retained much of the predictive performance of
    the full NIHSS (Tirschwell et al., 2002).
Client suitability

Can be used with: patients with stroke.

The NIHSS is designed so
that virtually any stroke will register some abnormality on the
scale.

Should not be used in:

  • The NIHSS can be administered to virtually any patient with
    stroke, however, a potential flaw with the NIHSS is that there may be
    a ceiling effect below the theoretical limit in patients with very
    severe stroke because many scale items cannot be tested in these
    patients (Muir, Weir, Murray, Povey, & Lees, 1996).
  • Can be estimated retrospectively from the admission neurological
    examination (Bushnell, Johnston, & Goldstein, 2001; Kasner et al.,
    1999; Williams, Yilmaz, & Lopez-Yunez, 2000), although actual
    testing is preferable.
In what languages is the measure available?

The NIHSS has been translated
into the following languages: (http://www.proqolid.org/)

  • Cantonese for Hong-Kong
  • Estonian
  • Hindi
  • Hungarian
  • Italian
  • Marathi
  • Portuguese
  • Telugu

The NIHSS has been translated and validated in the following
languages:

  • Chinese (Sun, Chiu, Yeh, & Chang, 2006)
  • German (Berger et al., 1999)
  • Spanish (Dominguez et al., 2006)