and Biofeedback Baselines
We hope that this chapter will successfully demystify psychophysiological assessment and enhance applied psychophysiologists' ability to formulate clinical questions and employ psychophysiological assessments to answer them.
The process of learning how to use psychophysiological assessments to answer relevant clinical questions first involves the review of some basic concepts in applied psychophysiology: (1) the measures that are generally used by applied psychophysiologists; (2) basic concepts in psychophysiology that are most relevant to applied psychophysiologists; and (3) general conditions that biofeedback therapists are likely to employ in such assessments. We stress what is perhaps the most important methodological issue in any type of assessment—that is, the temporal stability (i.e., reliability) of psychophysiological measures. We emphasize two conditions that are of essential importance to any psychophysiological assessment: baselines and adaptation periods.
The measures generally employed in psychophysiological assessments are surface electromyography (EMG); skin surface temperature (e.g., fingers, hands); electrodermal response; cardiovascular activity (heart rate, blood pressure, and vasomotor activity); and respiration (generally respiration rate and depth). Electroencephalography (EEG) requires specialized training and is outside the expertise of the average biofeedback clinician (as well as ourselves!), and therefore is not discussed in this chapter (but see Neumann, Strehl, & Birbaumer, Chapter 5, this volume, for such a discussion). For references about how surface EMG (hereafter referred to simply as EMG), skin temperature, and electrodermal responses are recorded and interpreted, see Peek, Chapter 4, this volume. For more on EMG, see Basmajian and DeLuca (1985). For measures of cardiovascular activity, see Larsen, Schneiderman, and DeCarlo Pasin (1986). For respiration, see Fried (1993), Kaufman and Schneiderman (1986), and Timmons and Ley (1994).