Objective: Mental fatigue occurring after a stroke or traumatic brain injury (TBI) often results in difficulties returning to work and pursuing social activities. No effective treatment of this condition is available today. In this study, we have tested a novel pharmacological strategy using the monoaminergic stabiliser (−)-OSU6162.
Methods: (−)-OSU6162 was given orally for 4 weeks in doses increasing from 15 to 45 mg b.i.d. to 12 patients suffering from mental fatigue, following upon stroke (n=6) or TBI (n=6). (−)-OSU6162 was compared with placebo using a double-blind, randomised cross-over design. Patients included were well rehabilitated physically with no gross impairment in cognitive functions other than those related to the mental fatigue.
Results: (−)-OSU6162 caused a remarkable improvement in mental stamina, as evaluated by a self-assessment scale on mental fatigue. Statistical significance was reached on the primary endpoint (Mental Fatigue Scale). There was a trend towards improvement in the secondary endpoints processing speed and attention. Principal component analysis showed an overall positive treatment effect in 7 of 12 patients. Beneficial responses were seen already during the first few days of active drug treatment. Increasing dosage caused no further improvement. Adverse reactions consisted of short-lasting mild nausea and attenuated appetite. These side effects disappeared upon dose reduction.
Conclusion: The monoaminergic stabiliser (−)-OSU6162 offers promise as a candidate for treatment of mental fatigue after a stroke or TBI.