INTRODUCTION: Adults with hearing loss who report difficulty understanding speech with and without hearing aids often also report increased mental or listening effort. Although speech recognition measures are well known and have been in use for decades, measures of listening effort are relatively new and include objective measures such as working memory tasks, pupillometry, heart rate, skin conductance, and brain imaging. OBJECTIVES: The purpose of this study is to evaluate an electroencephalogram (EEG)-based method to assess cognitive states during a speech in noise perception task. METHODS: High frequency alpha (11-13 Hz), low frequency alpha (8-10 Hz), and theta (4-7 Hz) frequencies were assessed with EEG during the Words-In-Noise test that utilizes seven different signal-to-noise ratios (SNR). Changes in high frequency alpha have been associated with cognitive demands and low frequency alpha has been associated with cognitive inhibition. Changes in theta have been associated with encoding information and increased listening effort. RESULTS: Results from the current study indicate a strong negative correlation between self-reported listening effort and speech in noise word recognition performance. Low frequency alpha power results suggest a power curve reflecting a point of maximum cognitive inhibition as a function of SNR. Results for high frequency alpha power show possible increased cognitive demand in lower SNR. Theta frequency shows no effect of SNR. DISCUSSION: Low frequency alpha results show a possible role of cognitive inhibition in words-in-noise speech recognition. High frequency alpha results show that lower signal-to-noise ratio conditions could increase cognitive demand. The EEG methodology used to measure theta may not be optimal to capture signal-to-noise changes. Understanding the neurological underpinnings of these frequencies could assist in the future development of an objective clinical tool to measure listening effort in patients with and without hearing loss.