Normal-hearing adults between 18 and 31 years of age were evaluated, including 50 males (mean age 24.72 years) and 50 females (mean age 23.77 years). The youngest male subject was 18 years old, and the youngest female subject was 18.16 years old. In contrast, the oldest male subject was 31.5 years old, and the oldest female subject was 31.83 years old. All of the participants in the study were students or employees of the University of Guarulhos.

Inclusion Criteria:

Subject inclusion criteria were:

• all of the subjects have to have auditory thresholds lower than 20 dB HL at all of the frequencies evaluated (octave frequencies between 0.25 to 8 kHz), bilaterally;
• type A tympanometric curves with presented ipsilateral and contralateral acoustic reflexes;
• 95% or higher correct responses for each ear in the dichotic digit test.

Subject inclusion criteria also included negative histories for audiologic, otologic, head trauma, and neurologic involvement.

Exclusion Criteria:

• Hearing loss;
• Auditory processing disorder;
• Histories of audiologic, otologic, head trauma, and neurologic involvement.