Using Nicotine to Reverse Age-related Auditory Processing Deficits

Using Nicotine to Reverse Age-related Auditory Processing Deficits: Human Psychophysics and Electrophysiology

The present study will evaluate the effects of both aging and nicotine on psychophysical tasks and electrophysiological measures. Nicotine will be administered to study participants in the form of gum that is available as an over-the-counter medication. The hypothesis is that nicotine will reverse the detrimental effects of aging on auditory processing. The proposed experiments will characterize the effects of nicotine and may eventually lead to improved treatments of hearing loss in a variety of patient populations and in healthy aging.

Study participants will be recruited in two age groups: young (18-28 years) and old (60-85). Each participant will participate in two psychophysical and electrophysiological test sessions. For each of the two sessions, the participant will be administered gum before the test. For one of these sessions, the gum will be polacrilex that contains 6-mg nicotine, and for the other session, the gum will be a placebo control. The study will be double-blind, meaning that neither the experimenter nor the participant will know whether the participant has received nicotine or placebo for a given session. The study has a cross-over design, meaning that all participants will receive both nicotine and placebo in separate sessions. Finally, the order of drug administration will be counterbalanced, meaning that equal numbers of participants will receive 1) nicotine in session one and placebo in session two, and 2) placebo in session one and nicotine in session two.

Inclusion Criteria:

• between 18 and 85 years of age
• non-smokers with a score of 0-2 out of 10 maximum on the Fagerström index of smoking dependency
• cognitive performance within two standard deviations of the CERAD mean

Exclusion Criteria:

• less than 18 or greater than 85 years of age
• deafness or excessive hearing loss
• smokers with a score between 3 and 10 on the Fagerström index of smoking dependency
• history of psychiatric illness, neurological disorders, diabetes mellitus, renal failure, or cardiovascular disease
• regular use of prescription medications (excluding oral contraceptives)
• drug dependency