RESUMEN
Objective To optimize the f2/f1 frequency ratios for DPOAEs and to evaluate the effects in the measurement of normal and hearing loss ears .Methods Seven of 18 guinea pigs were randomly selected and DPOAE measurements were performed ,using the L2 stimulus levels of 25 ,40 and 60 dB SPL ,L1 = 0 .46 L2 +41 dB SPL .The stimulus frequency f2 ranged from 1 to 16 kHz ,and the f2/f1 ratio ranged from 1 .1 to 1 .5 .The maxi-mum DPOAEs (Ldp ) were determined and the corresponding f2/f1 ratios were used as the parameters for DPOAE measurement .The inner ears of all the 18 animals were operated unilaterally .One week later ,They were divided in-to 2 groups(A and B) and DPOAE measurements were performed with the optimal f2/f1 ratio in group A and with the fixed f2/f1 ratio in group B separately .Results When f2 ranged from 1~2 kHz ,the optimal f2/f1 ratio rose from 1 .25 to 1 .44 ;then it reduced to 1 .17 when f2 was 8 kHz .When f2 ranged from 8~16 kHz ,the optimal f2/f1 ratio rose slightly to 1 .24 .Compared with the fixed f2/f1 ratio in group B ,using the optimal f2/f1 ratio in group A could determine more precise DPOAEs in the operated ears ,especially in the f2 range from 1~4 kHz .Conclusion Using optimal f2/f1 ratios can promote the sensibility for the DPOAE measurements .