Is the Kennard effect supported by clinical evidence?

Abstract

The objective of the study was to evaluate the so-called Kennard effect, i.e., the existence of a negative correlation between recovery and age. Thirty-eight elderly patients(median age 71 years, range 60-81) suffering from their first stroke were enrolled. The mean interval since the stroke was 15 days. Patients entered a 60-day rehabilitation pro -gram. Their functional condition was assessed by means of the functional independence measure (FIM). Only FIM values under 36 at admission were considered. Computerized tomographic (CT) or magnetic resonance imaging (MRI) scans were performed in all cases. The type of lesion was ischemic in 24 cases, hemorrhagic in 7 cases and 7 cases had more than one lesion. The patients' families were contacted after one year for a follow-up and all of them gave their consent. The survivors were examined again. The FIM score at discharge and the corresponding values at follow-up were statistically compared by means of Wilcoxon test (two-tailed). The FIM value at admission of the whole population had the median value of 27.5. None of these patients died during their stay at our rehabilitation center and their median FIM value at discharge was 34.5, a value still indicating high disability. After one year, 22 were still alive at home (57.9 %). Their FIM median value was 46. The difference was significant compared to discharge (Z = -3.228, p = 0.001). Three patients scored 85, 87 and 88, respectively, although none of them received rehabilitation treatment. In conclusion, our results indicate that restorative processes are still active in elderly patients, despite previous stroke and existing comorbidities. Some of the elderly patients of our group could approach to independence, although they displayed a very low FIM value at admission.