Neuropsychological rehabilitation of higher cortical functions after brain damage

Neuropsychological interventions for impairments of higher cognitive functions can be divided into four different approaches: restoration of function, compensation, physiological stimulations, and metacognitive strategies. Training that aims to restore an impaired function or to increase processing speed or capacity is repetitive and often stereotyped. Such training may lead to task-specific learning with little generalization, as may be observed in particular in the domain of attention rehabilitation. However, it remains a matter of debate whether such practice effects really reflect the restoration of function or improved processing due to preserved procedural learning skills. For some cognitive domains (such as memory), restoration of function is mostly impossible; consequently, training mainly relies on compensatory strategies. For example, enhancement of learning may be achieved by improving memory encoding with mental imagery, while everyday memory is supported with systematic training of external aids, such as, memory notebooks. A third approach is applied in neglect rehabilitation and uses physiological stimulations to bias attention and sensory representations (e.g. optokinetic stimulation) or decrease interhemispheric inhibition (transcranial magnetic stimulation). Finally, the fourth approach is to structure behaviour and to enhance metacognitive abilities; this strategy is applied in the rehabilitation of complex problem-solving skills and impaired emotional regulation. Although it is difficult to control experimental biases in intervention studies targeting cognitive and behavioural disturbances, an increasing number of controlled clinical trials provide evidence for the efficacy of each of the four therapeutic approaches.