  The NASA Kepler spacecraft data revealed a large number of multimode
nonradially pulsating gamma Dor and delta Sct variable star candidates. The
high precision long time-series photometry makes it possible to study amplitude
variations of the frequencies. We summarize recent literature on amplitude and
frequency variations in pulsating variables. We are searching for amplitude
variability in several dozen faint gamma Doradus or delta Scuti variable-star
candidates observed as part of the Kepler Guest Observer program. We apply
several methods, including a Matlab-script wavelet analysis developed by J.
Jackiewicz, and the wavelet technique of the VSTAR software
(http://www.aavso.org/vstar-overview). Here we show results for two stars, KIC
2167444 and KIC 2301163. We discuss the magnitude and timescale of the
amplitude variations, and the presence or absence of correlations between
amplitude variations for different frequencies of a given star. Amplitude
variations may be detectable using Kepler data even for stars with Kepler
magnitude >14 with low-amplitude frequencies (around 100 ppm) using only one or
a few quarters of long-cadence data. We discuss proposed causes of amplitude
spectrum variability that will require further investigation.
