Changes in impairment and disability from the third to the sixth month after stroke and its relationship evaluated by an artificial neural network

Functional recovery in a rather late stage after stroke was examined in 70 stroke patients using the Stroke Impairment Assessment Set (SIAS) and the Functional Independence Measure (FIM(SM)). The SIAS and the FIM(SM) were administered at three and six months after the onset of stroke. Motor items and the abdominal manual muscle testing item improved in more than 30 percent of patients. The motor subscore of the FIM(SM) changed from 60.8 to 73.4, and the cognitive subscore changed from 28.4 to 30.4. The relationship between impairment and disability was evaluated using the neural network method with the software, Skiltran. The change of the FIM(SM) motor subscore from three months to six months was used as an output variable, and the change in the SIAS items and the FIM(SM) motor subscore were included as input variables. As a result of the connection weight obtained from this network, the change in the fifth motor item (one of the tone items, abdominal manual muscle testing) and the unaffected side grip as well as the FIM(SM) at three months had a strong connection to the change of the FIM(SM). It is compatible with ordinary experience that function of both the affected and unaffected side influences the level of disability. Contribution of the impairment to the disability indicates the importance of taking into consideration the impairment for predicting prognosis and selecting adequate treatment when we carry out stroke rehabilitation. In conclusion, we described the relationship between the SIAS and the FIM(SM) using the neural network in stroke patients and proved the importance of the impairment to predict the outcome of disability.