Stroke Recovery Calculator

Stroke recovery criteria

This outcome clinical tool examines the result from the NIH stroke scale, the time from stroke onset and the DWI lesion volume to determine the likelihood of positive outcome (defined here as recovery) in patients suffering from stroke.

The National Institutes of Health Stroke Scale (NIHSS) evaluates neurological function in patients diagnosed with or suspected of stroke.

The examination is performed by a medical professional and results in stratification of stroke severity after checks to the left and right motor and cortical function.

Time from stroke onset is taken into account in the evaluation because from 12 hours to 7 days after stroke, an improvement in neurologic impairment can be observed in most uncomplicated cases.

The major component of recovery after stroke is likely to happen during the first three to six months.

The diffusion-weighted imaging lesion volume test offers information on the ischemic brain injury and the integrity of the corticospinal tract, as examined within 36 hours of stroke onset.

Excessive corticospinal tract injury is likely to carry a poor outcome prognosis.

DWI is a method sensitive in the early detection of small infarcts. Its sensitivity is reported to be 88 – 100% whilst its specificity is 86 – 100%.

The three parameters were found to have better prediction value together than alone and the model proved 0.77 sensitivity and 0.88 specificity in subsequent validation studies.

Result interpretation

The table below introduces the correlation between the scores from this original predictive model and recovery likelihood in percentage:

It was found that patients with hemorrhagic stroke have a poorer prognosis than patients with ischemic stroke (85% of stroke in US), and a higher chance of developing complications.

These are the outcomes for stroke patients:

■ 35% gain functional independence;

■ 25% are left with minor disability;

■ 40% are left with severe disability.

Degree of functional independence after stroke is assessed through clinical scales such as the modified Rankin Scale or the Barthel Index.

About the study

This predictive model, created by Baird et al. in 2001 is based on a three-phase study on 66 patients from a North American hospital.

The National Institutes of Health Stroke Scale (NIHSS) score was measured at the time of scanning and the MR DWI within 36 h of stroke onset.

Logistic regression model was applied to data from another cohort of patients from an Australian hospital.

It was found that the three parameters (NIHSS score, time from onset and MR DWI) have the best predictive capability, better than any other patient factor accounted for after admission to hospital.

Problems after stroke

Stroke intervention needs to be rapid to diminish the risk of complications and long term impairment. However, this is dependent on the size and location of the ischemic attack.

The Gold Standard is stroke IV treatment with tPA (tissue Plasminogen Activator) which dissolves the blood clot, thus improving blood flow to the brain.

It was found that early tPA can positively influence recovery rate.

The most common problems, patients who suffer a stroke are left with, include:

■ Paralysis;

■ Muscle spasticity;

■ Weakness in limbs;

■ Numbness or tingling;

■ Fatigue unrelieved by rest;

■ Increased sensitivity to pain.

Some of the cognitive problems include short term memory loss, loss of perception, lack of concentration and attention or aphasia. These mostly depend on the area of the brain affected.

Original source

Baird AE, Dambrosia J, Janket S, Eichbaum Q, Chaves C, Silver B, Barber PA, Parsons M, Darby D, Davis S, Caplan LR, Edelman RE, Warach S. A three-item scale for the early prediction of stroke recovery. Lancet. 2001; 357(9274):2095-9.

Other references

1. Jongbloed L. Prediction of Function After Stroke: A Critical Review. Stroke. 1986; 17(4).

2. Goldstein LB. Modern Medical Management of Acute Ischemic Stroke. Methodist Debakey Cardiovasc J. 2014; 10(2): 99–104.

3. Knecht S, Hesse S, Oster P. Rehabilitation After Stroke. Dtsch Arztebl Int. 2011; 108(36): 600–606.