Despite the interesting implications of the present findings, it should
be kept in mind that the relationship between APS improvement and
verbal memory was only a medium-sized effect, and as previously
noted, our study included the administration of only 1 h of ATCT and
one ATCT task (Sound Sweeps). Future research should examine these
early indicators of auditory learning in the context of a therapeutic
“dose” of ATCT in a larger sample to determine whether they can truly
distinguish individuals who vary by degree of cognitive enhancement.
Other limitations of the present study include the restricted range of
perceptual improvements permitted within the Sound Sweeps exercise
(i.e. participants automatically progressed to the next training level
after reaching a predetermined perceptual threshold beyond their base-
line score — the best scores obtained by participants may therefore un-
derestimate their “true” auditory learning capacity). The present study
also lacked experimental control of medications and nicotine use.
Medication-related exclusion criteria were omitted in order to improve
generalizability of findings to real-world community-dwelling patients.
Patients in the study were prescribed heterogeneous medication regi-
mens, including agents that may enhance or blunt ATCT's effects