Massage And Music Therapies Attenuate Frontal Eeg Asymmetry In Depressed Adolescents

Adolescence, Fall, 1999 by Nancy Aaron Jones, Tiffany Field

ABSTRACT

EEG asymmetry, specifically greater relative right frontal activation, is associated with negative affect. Depressed adults show stable patterns of this asymmetry. The present study assessed the effects of massage therapy and music therapy on frontal EEG asymmetry in depressed adolescents. Thirty adolescents with greater relative right frontal EEG activation and symptoms of depression were given either massage therapy (n = 14) or music therapy (n = 16). EEG was recorded for three-minute periods before, during, and after therapy. Frontal EEG asymmetry was significantly attenuated during and after the massage and music sessions.

Listening to music has been associated with decreased stress hormone (cortisol) levels in depressed adolescents (Field, Martinez, Nawrocki, Pickens, Fox, & Schanberg, 1998). Massage therapy has led to a reduction in anxiety, depression, and stress hormone in depressed adolescent mothers (Field, Grizzle, Scafidi, & Schanberg, 1996). Further, music has been found to shift frontal EEG patterns toward symmetry in adolescents who were depressed (Field et al., 1998), and massage therapy has attenuated EEG asymmetry in infants of depressed mothers (Jones, Field, & Davalos, 1998). The latter findings are surprising given that frontal EEG asymmetry is believed to be stable (Tomarken, Davidson, Wheeler, & Kinney, 1992). For example, previously depressed adults were found to have greater relative right frontal EEG activation even though they no longer showed behavioral symptoms (Henriques & Davidson, 1990), suggesting that it is a physiological marker for depression, independent of symptomatology.

Greater relative right frontal EEG activation has been associated with negative affect and the tendency to withdraw, whereas greater relative left frontal EEG activation has been associated with the opposite (Fox, 1991, 1994; Tomarken & Davidson, 1989). The present study investigated the effects of massage therapy and music therapy in a sample of depressed adolescents with greater relative right frontal EEG activation. These therapies were expected to shift EEG patterns toward symmetry.

METHOD

Participants

Thirty adolescents, with a mean age of 18.8 years, were randomly assigned to massage (n = 14) and music (n = 16) groups. They were unmarried, and their socioeconomic status was low (M = 4.4 on the Hollingshead Index). Sixty percent were African American and 40% were Hispanic.

Adolescents' scores on the CES-D (Center for Epidemiologic Studies Depression Scale; Radloff, 1977) were greater than 16, indicating depression. The adolescents also met DISC (Diagnostic Interview Schedule for Children; Robins, Helzer, Croughan, & Ratcliff, 1981) criteria for dysthymia or major depressive disorder. In addition, their baseline EEG patterns indicated greater relative right frontal activation.

Procedure

EEG. Three-minute EEG recordings were obtained prior to, during, and after the massage/music sessions. A stretchable lycra EEG cap was placed on the participant's head, with electrodes positioned using the international 10--20 system. Electrode gel (to provide good conductance) and Omni-prep gel (gently abrading the scalp) were used at midfrontal (F3 and F4), parietal (P3 and P4) and vertex (Cz) sites. Impedances were brought below 5,000 ohms (the site was reabraded until optimal impedance was obtained). In addition, EOG (electrooculogram) recordings were obtained using two Beckman mini-electrodes, placed at the outer canthus and supraorbital positions of one eye.

The signal was passed through a Grass Model 12 Neurodata Acquisition System. The output from the amplifiers was directed to a Dell 325D computer, which was fitted with an Analog Devices RTI-815 A/D board. Data were saved to hard disk using data acquisition software (Snapstream, v. 3.21, HEM Data Corp.).

EEG data were screened for artifact, such as that caused by eye movement (using EOG recordings) and gross motor movement. Remaining data were submitted to a discrete Fourier transform using a Hanning window with 50% overlap. This produced power values for the standard adult frequency bands in picowatt ohms (which is equal to a microvolt squared) for each lead. Delta (1--3 Hz), theta (4--7 Hz), alpha (8--12 Hz), and beta (13--30 Hz) frequency bands were analyzed. Frontal and parietal EEG asymmetry scores were computed. These difference scores reflect the power in one hemisphere relative to the power in the contralateral hemisphere [In(right) minus In(left)]. Negative scores indicate greater relative right hemisphere activation, whereas positive scores indicate greater relative left hemisphere activation (Davidson, 1988).

Massage. Massage therapy was provided by a professional massage therapist for 15 minutes. The fully clothed adolescents sat in a special massage chair while receiving a standard Swedish massage. This consisted of long, broad strokes, using moderate pressure, administered to the back, arms, hands, and neck (see Field, Ironson, Scafidi, Nawrocki, Goncalves, Pickens, Fox, Schanberg, & Kuhn, 1996).