The effect of methylphenidate on test performance in the cognitively impaired aged.

It was hypothesized that a central nervous system stimulant with relatively weak peripheral effects would facilitate test performance in the cognitively impaired aged. Twelve elderly subjects participated in a counter-balanced, crossover comparison of 10 mg methylphenidate, 30 mg methylphenidate and placebo. All treatments were administered double-blind as a single dose of oral medication. Neither dosage of active medication was found to effect psychomotor or psychological test performance, subjective report, heart rate or blood pressure. A subsequent open trial of 45 mg methylphenidate resulted in heart rate, blood pressure and subjective changes in two of eight subjects but no effects on test performance. The results suggest that cognitive performance in the moderately impaired aged is unimproved following administration of methylphenidate, and perhaps similar sympathomimetic amines, below a dosage level associated with clinically significant peripheral effects.