Decision time in stroke patients have a high tendency to be increased disproportionately as the complexity of the task increased - this is known as the "complexity-effect- (Gerritsen, Marleen J.J.; Berg, Ina J.; Deelman, Betto G.; Visser-Keizer, Annemarie C.; Meyboom-de Jong, Betty, 2002, p1). The complexity-effect has a higher rate in left hemispherical stroke patients but it was only the accuracy of the responses that seemed to be affected and not the reaction times. Therefore, left hemisphere patients made more mistakes, but they were not slower than right hemisphere patients. In the study done by Marleen J.J. Gerritsen (2002), there was a difference found left hemisphere and right hemisphere patients. Both groups showed to take longer in the reaction times than their control group but right hemisphere patients were much slower on simple reaction time tests; this theory has been backed up by other studies as well showing similar results. Reaction time in patients has many factors that also need to be taken into account - such as aphasia and neglect. .
.
Aphasia is a disruption in a person's ability to use language to communicate with others. The difficulty may be either receptive (the person has difficulty understanding what is said to them or what they read) or expressive (the person has difficulty recalling words or writing). In many cases the person will have a combination of both receptive and expressive difficulties. In addition, the difficulties experienced may range from very mild " the person may have slight difficulties naming things, to more severe " the person is not able to understand or use any language. Aphasiacs tend to have an impaired attention capacity as well as slower reaction times and complexity-effect but as of yet there is no correlation between the severity of comprehension deficits and attentional capacity. Moreover, many patients, aside from mental slowness and language deficits, will also have a hard time with speech.
