Long-term maintenance of fundamental frequency increases in male-to-female transsexuals.

Fundamental frequency for 10 male-to-female transsexuals at long-term follow-up (FUF0) was compared to fundamental frequency at initial consultation (IF0) and at discharge from treatment (DF0). Fundamental frequency (F0) values for the three occasions were significantly different [F(2,18) = 24.79, P < .0001] Group mean fundamental frequencies were 125.5 Hz at initial consultation, 168.1 Hz at discharge, and 146.5 Hz at follow-up. There was a moderate but nonsignificant correlation [r(8) = 0.474, P > .05 ns] between the number of intervention sessions and mean F0 achieved by subjects at discharge (DF0). There was a significant correlation between the number of treatment sessions and the maintenance of F0 increases [r(8) = 0.745, P < .05], although the size of the correlation was more modest (r = 0.476) when the data from one subject who had received 90 treatment sessions were removed.