[The prognostic value preoperative promontory testing in Japanese cochlear implant patients]

Evaluation of Temporal Difference Limen in Preoperative Non-Invasive Ear Canal Audiometry as a Predictive Factor for Speech Perception after Cochlear Implantation

The temporal difference limen (TDL) can be measured with noninvasive electrical ear canal stimulation. The objective of the study wa to determine the role of preoperative TDL measurements in predicting patients’ speech perception after cochlear implantation. We carried out a retrospective chart analysis of fifty-four cochlear implant (CI) patients with preoperative TDL and postoperative bisyllabic word recognition measurements in Helsinki University Central Hospital between March 1994 and March 2011. Our results show that there is no correlation between TDL and postoperative speech perception. However, patient’s advancing age correlates with longer TDL but not-directly with poorer speech perception. The results are in line with previous results concerning the lack of predictive value of preoperativ TDL measurements in CI patients.

Value of the Promontory Stimulation Test in Predicting Speech Perception After Cochlear Implantation

BACKGROUND AND OBJECTIVES

To determine the role of the promontory stimulation test (PST) in cochlear implantation (CI), we evaluated the correlations between PST parameters and the results of speech perception tests after CI.

SUBJECTS AND METHOD

With use of a retrospective review of the medical records of 58 patients, the GAP50, GAP100, TDL50, and TDL100 parameters of the PST were compared with the results of speech perception tests at fixed time points after CI. Spearman's rank-order correlation coefficient was used in statistical analyses.

RESULTS

GAP100 scores were correlated with all results of speech perception tests at all time points after CI (r = 0.309-0.509, P = .001-0.010), and TDL100 scores were correlated with the results of open set one- and two-syllabic word tests at 1 month after CI (r = 0.288, P = .028); no other significant correlations were found. The GAP100 scores for postlingually deaf patients, especially for gap intervals up to 100 ms, were correlated with all results of speech perception tests after CI. A stepwise multiple regression analysis revealed that the GAP100 score is the only variable that was significantly correlated with the results of speech perception tests. The duration and onset age of deafness did not significantly affect the results.

CONCLUSION

The PST may be a useful tool for predicting the prognosis of CI. The GAP100 score, especially for gap intervals up to 100 ms, might be useful in predicting the results of speech perception tests after CI as well as in determining the optimal site for CI in postlingually deaf patients without residual hearing.