In vitro comparison of the Groningen high resistance, Groningen low resistance and Provox speaking valves.

This paper compares the physical parameters of the newer Groningen low resistance and Provox indwelling laryngectomy prostheses with the established and original Groningen device. In vitro pressure/flow profiles were determined, using specially designed apparatus, in 44 standard Groningen high resistance (GHR), 37 Groningen low resistance (GLR) and 19 Provox tracheo-oesophageal prostheses prior to insertion. GHR valves had significantly higher forward opening pressures than both the newer valves and the GHR was significantly higher than the Provox (p < 0.01: Mann-Whitney U-test). The mean forward resistance of GHR was significantly higher than that of both; the Provox valve was significantly lower than that of GLR (p < 0.0001: Mann-Whitney U-test). This may be of relevance with respect to patient acceptability, voice quality and effective duration of valve action.