Stroke outcomes are usually classified according to survival (death), impairment (sign and symptoms of the underlying pathology), disability (limitations in functional activities), handicap (limitations in role functions), and quality of life (patient’s general well-being resulting from physical, psychological, and social aspects of life) (Barker-Collo and Feigin 2006).
Mortality after stroke is high, especially in the acute phase, but also in the following years. At 30 days post-stroke the mortality rate is approximately 19-25%, at 12 months 35-40%, and after 5 years 55-60% (Donnan et al. 2008;Ellekjaer et al. 1997;Hankey et al. 1998;Hankey et al. 2000;Hankey 2003). The mortality rate during the first 12 months is equivalent to a 10-fold risk compared to the general population of same age and sex. The major causes of death during the first year are stroke related (brain oedema and secondary complications such as infections and venous thrombosis), while a cardiovascular disease is the major cause one to five years post-stroke (Hankey et al. 2000).
However, for most patients, a stroke is not lethal, but lead to functional impairments affecting their daily lives. According to figures from the Swedish Stroke Registry (Socialstyrelsen 2004), as many as 80% of stroke survivors lived in their own house two years after the stroke. However, a large proportion was dependent in primary (personal) and secondary (instrumental) activities of daily living (ADL). With respect to primary ADL, 36% were dependent in outdoor mobility, 24% in grooming and dressing, 18% in toilet use, 15% in indoor mobility, and 7% were dependent in situations related to eating and drinking. The proportion dependent in secondary ADL was even higher. More than 60% needed help in preparing meals, local shopping, and housework activities.
A similar picture is reported in two population-based studies from Auckland, New Zealand.
Almost 75% of the stroke survivors were living at home six months after the stroke (Bonita 1992). At three years post-stroke more than 50% of the survivors reported incomplete recovery (i.e. dependent in at least one secondary ADL-actitvity), and, of these, 20% were dependent in at least one primary ADL-activity) (Bonita et al. 1997).
Considering the serious impact on functional outcome, it may not come as a surprise that both an association between stroke and reduced quality of life in the patient (Carod-Artal and Egido 2009), and an increased psychosocial burden on the caregiver is well-documented (Thommessen et al. 2001;Thommessen et al. 2002;Wyller et al. 2003).
Different impairments in functional abilities may be measured by validated scales like Barthel Index (BI) (Mahoney and Barthel 1965), the Frenchay Social Activities Index (FAI) (Schuling et al. 1993), the Functional Independence Measure (FIM) (Hamilton et al. 1994;Kidd et al.
1995), and the modified Rankin Scale (mRS) (van Swieten et al. 1988).
BI measures impairments in personal ADL and comprises ten different aspects of self-care, including incontinence (bowels and bladder), grooming, toilet use, feeding, transfers bed to chair and back, mobility on level surfaces, dressing, stairs, and bathing. Total score can vary from 0 (maximum impairment) to 20 (functional independence).
FAI is a measure of instrumental ADL and consists of 15 items, including preparing main meals, washing up, washing clothes, light and heavy housework, local shopping, social outings, walking outside, actively pursuing hobby, driving car/bus travel, outings/car rides, gardening, household/car maintenance, reading books and gainful work. Minimum score is 15 (inactive) and maximum is 60 points (very active).
FIM consists of 18 items and addresses two basic domains, physical (13 items) and cognitive (5 items). The physical items resemble those found in the BI and include measures of self-care, sphincter control, mobility and locomotion, while the cognitive items measures aspects of social interaction, problem-solving and memory. Total FIM-score can vary from 18 (complete dependence/total assistance) to 126 points (complete independence). Subscale scores of the physical and cognitive domains can be calculated separately, and may yield more useful information rather than relying solely on the total FIM score.
In contrast to the BI, FAI and FIM which focus on ability to perform specific tasks, the mRS is a global disability scale. It is quick and easy to administer, and consists of seven categories:
0 (no symptoms), 1 (no significant disability despite symptoms; able to carry out all usual duties and activities), 2 (slight disability; unable to carry out all previous activities but able to look after own affairs without assistance), 3 (moderate disability; requiring some help, but able to walk without assistance), 4 (moderate severe disability; unable to walk without assistance, and unable to attend to own bodily needs without assistance, 5 (severe disability;
bedridden, incontinent, and requiring constant nursing and attention, and 6 (dead).
Scoring is done on the basis of the adminstrator’s subjective judgement. A limitation is the lack of clear cut criteria to assign grades, which may reduce the reliability of the scale. A structured interview with specific questions to grade each category has been developed and may enhance reliability.
The type of stroke, its size and topographical location have an impact on the prognosis. The prognosis for patients with hemorrhagic strokes is more severe than for ischemic strokes with a 30 days mortality rate of 38-50% (Ellekjaer et al. 1997). Stroke severity and topographical location according to the OCSP-classification have been shown to predict mortality in ischemic strokes. TACS have the worst prognosis with a 12-months mortality rate of 60%, followed by PACS and POCS with 15-20%, while LACS have the best prognosis with a rate of 11% (Bamford et al. 1991).
For the stroke survivors, size and topographical location of the lesion seem more important than stroke type (ischemic or hemorrhagic) in relation to functional prognosis. Less than one in ten patients suffering a TACS reaches independence within one year (defined as mRS-score=0-2), in contrast to approximately six in ten of those with PACS, POCS or LACS (Bamford et al. 1991;Fure et al. 2006b).
Improvement in functional impairments may be expected in the majority of patients with first-ever stroke, but mainly takes place within the first 6 months after a stroke (Jorgensen et al.
1999). In the Copenhagen Stroke Study, neurological (measured with the SSS) and functional recovery (measured with the BI) was assessed weekly from stroke onset to end of
rehabilitation, and again six months later. The time course of functional recovery was strongly correlated with the initial neurological stroke severity, but for 95% of the patients the
functional recovery was completed within 13 weeks from stroke onset. Patients with mild strokes reached their best function within 9 weeks, moderate strokes within 13 weeks, severe strokes within 17 weeks, and very severe strokes within 20 weeks after stroke onset. Both compensational and intrinsic neuronal mechanisms probably contribute to the functional recovery seen after a stroke. Compensation involves teaching patients with persistent functional deficits new approaches to perform important tasks of daily living, either by using the affected or non-affected limb. In the Copenhagen Stroke Study, compensation was associated with younger age, less severe strokes, and more intact higher cortical functions.
Neurological recovery involves at least three processes: Restoration of cerebral blood flow by spontaneous reperfusion, resolution of oedema or hemorrhage, and transfer of lost neural function to intact parts of the brain.
An understanding of factors affecting the prognosis is important. There are strong indications that cognitive abilities may be at least as important as sensori-motor functioning in predicting outcome.