Background:
Improvement in central auditory processing (CAP) test results has been reported in children with attention deficit disorder (ADD) who have been treated with methylphenidate (MPH).

Objective:
To determine the effect of MPH on CAP tests in school-aged children and adolescents with ADD, with or without hyperactivity.

Methods:
A systematic review was carried out following the Prisma methodology in The Cochrane Library, Medline, Embase, and Lilacs data bases. Randomized (RCT) and non-randomized (NRCT) clinical trials were included, involving male and female patients between 6 and 18 years old, with normal audition and intelligence and diagnosed with ADD; they were given MPH treatment and the results of CAP tests were compared to placebo or non-MPH treatment.

Results:
Five studies (two RCTs and three NRCTs) reported on 187 participants of both sexes, between 6 and 15 years old, of which 135 individuals met the diagnostic criteria for ADD and 44 presented ADD with central auditory processing (CAP) disorder, with 52 individuals used as controls. MPH treatment produced an increase in the performance of the speech-in-noise test (0.38 SMD [95% CI 0.11 to 0.66] [Z = 2.7, p = 0.007]), staggered spondaic words test (0.35 SMD [95% CI 0 to 0.69] [Z = 1.95, p = 0.05]) and filtered word test, frequency pattern test, and phonemic synthesis test (0.35 SMD [95% CI 0.01 to 0.68] [Z = 2.03, p = 0.04]. Also, continuous performance tests showed a decrease in the number of errors and inattentions (–0.77 SMD [95% CI –1.17 to –0.37] [Z = 3.79, p = 0.0002]) concerning the control group. The evidence was consistent, accurate, and with low heterogeneity.

Conclusions:
MPH has a significant and favorable effect on the CAP tests of children and adolescents with ADD.