Objective: To evaluate the effect of methylphenidate on cognitive function especially on working memory and visuospatial attention in the patients with traumatic brain injury (TBI).
Method: Eighteen subjects, 16 males and 2 females, with TBI were enrolled. Their mean age was 34.2 years old. A double-blind placebo-controlled study was designed. The baseline cognitive assessment was performed before the administration of drug. Two days after the baseline study, 20 mg of methylphenidate or placebo was administered. The second cognitive assessment was performed 2 hours after the treatment. The follow-up assessment conducted two days after the second test. Cognitive assessments consisted of 'one-back working memory task' and 'endogenous visuospatial attention task', designed using SuperLab Pro 2.0Ⱂ software.
Results: In one-back working memory test, there was significant improvement of response accuracy in methylphenidate group in comparison with placebo group (p<0.01). Significant shortening of reaction time was also seen after the administration of drug in methylphenidate group (p<0.05). In endogenous visuospatial attention test, significant improvement of response accuracy was noticed after the administration of drug in methylphenidate group (p<0.05).
Conclusion: These results demonstrated that the administration of methylphenidate was beneficial in improving cognitive function following TBI. The effect was prominent in the accuracy of working memory.
Outcome following brain injury is influenced by several factors, including on early medical and rehabilitative intervention, an integrated interdisciplinary team approach to treatment, and the patient's motivation and ablility to cooperate in rehabilitation efforts. Methylphenidate(MP) is a central stimulant that blocks the reuptake of serotonin and norepinephrine, and also it has a dopaminergic activity by releasing the dopamine from dopamine stored vesicles. Dopamine plays an important role in cognitive and affective brain functions. Methylphenidate has been used in an attention deficit disorder with hyperactivity in the pediatric clinic and for various types of depression and narcolepsy. Clinical research has not irreputably proved or disproved the effectiveness of MP for the improvement of cognitive function in brain injured patients.
This report presents five cases who were treated by MP for the improvement of cognitive function in brain injured patients. Among five cases, 3 cases suffered from hemorrhagic strokes and 2 cases from tranmatic brain injuries.
Three cases were in drowsy stateand 2 cases were semicomatous. After MP(10 mg) was ingested per oral route before breakfast, we evaluated patients' cognitive function by the Functional Independence Measure(FIM), Rappaport Disability Rating Scale(DRS), Mimi-mental State Examination(MMSE), Galveston Orientation and Amnesia Test(GOAT) and the clinical state as well as side effects. Based on the results from the study we suggest cautionally that MP would be useful for the treatment of brain injured pateints who had decreased cognitive function to induce an early participation of rehabilitation programs. Further prospective study is required with a large control group and affected group, to confirm our preliminary results.