The local segmental dynamics of anthracene-labeled cis-1,4-polyisoprene in dilute solution have been studied as a function of temperature (298-323 K) and pressure (0.1-150 MPa) in several solvents (dioctyl phthalate, n-dodecane, squalane, and toluene). This range of temperature and pressure afforded a viscosity range of 0.55-494 mPa.s. Previous studies of cis-1,4-polyisoprene as a function of temperature at ambient pressure have revealed that these motions scale as a fractional power of the solvent viscosity,, thereby violating Kramers' theory which predicts tau(c) similar to eta. Findings reveal quantitatively similar behavior is observed when the solvent viscosity is varied by pressure at fixed temperatures.