Fig. 2.

Normalized mean performance (n=12) on the psychomotor vigilance test (a: PVT) and delayed match-to-sample test (b: DMS) across five weeks of treatment. Reaction time and number of correct trials are expressed as the percentage change from performance at baseline. Subjects showed progressively faster responding in the PVT, and progressively more accurate responses in the DMS, over weeks of laser treatment. The apparently weaker mean effects for week 5 were due to 3 subjects approaching ceiling performance and missing the last session