Postoperative Speech Reception Threshold Research Articles

CT evaluation of congenital aural atresia: what the radiologist and surgeon need to know.

The preoperative evaluation of aural atresia and stenosis is strongly dependent upon high resolution CT. We have devised a 10 point surgical rating scale based on high resolution CT of the temporal bone that will provide radiologists with a stepwise method of evaluating these scans and will allow them to communicate these findings to otologic surgeons in a consistent fashion. We prospectively evaluated 1,500 patients with aural atresia or stenosis for eight critical areas of temporal bone anatomy, each area receiving 1 rating scale point, with the exception of the presence of a stapes, which received 2 points. The appearance of the external ear received the final point on the rating scale since the external ear is formed earlier than the middle ear and helps to predict its deformities. The presurgical score was utilized in selecting surgical candidates and was correlated with the intraoperative findings as well as the postsurgical results by comparing pre- and postoperative speech reception threshold. Patients with a presurgical rating of < or = 5 were not considered surgical candidates. Otherwise, the percentage of successful surgeries corresponded roughly to the rating scale. Thus, a presurgical rating of 8 points translates into an 80% chance of restoring hearing to normal or near-normal levels.

GRADING SYSTEM FOR THE SELECTION OF PATIENTS WITH CONGENITAL AURAL ATRESIA

It is generally recognized that surgery for congenital aural atresia is difficult. In an effort to select those patients who have the greatest chance of success, we have developed a grading scheme based on the preoperative temporal bone CT scan and the appearance of the external ear. Patients are graded on a possible best score of 10. The stapes is assigned the highest rating (2 points), while all other entrees on the scale are 1 point. The grade assigned preoperatively has been shown to correlate well with the patient's chance of success, herein defined as a postoperative speech reception threshold of 15 to 25 dB. A patient with a preoperative grade of 8/10 would, therefore, have a 80 percent chance of achieving this threshold. Patients with scores of 5/10, or less, are not considered surgical candidates, because the risk of the operation would outweigh the potential benefits. We have found that the grading system allows us to avoid impossible surgical cases while allowing for a reasonable prediction of the hearing outcome.

Stapedectomy: Long‐term hearing results

The initial improvement in hearing following stapedectomy usually deteriorates with the passage of time. We studied the long-term results of stapedectomies performed on 42 patients (49 ears) between 1959 and 1969 who had a minimum follow-up of 18 years. Both air conduction (AC) and bone conduction (BC) thresholds progressively deteriorated over the long term. The degree of BC loss paralleled that expected from presbycusis alone. A greater deterioration was noted in the AC levels, producing a recurrent conductive hearing loss in the speech frequencies. Age at the time of surgery had no effect on the long-term outcome. Comparison of the average preoperative speech discrimination scores (SDS) to the 1-year postoperative SDS and the long-term SDS revealed a 1.1% and 16.7% drop, respectively. The improvement in the average speech reception threshold (SRT) obtained 1 year postoperatively deteriorated by less than 1 dB per year over the long term. Patients with a higher SDS (more than 95%) preoperatively fared better in the maintenance of speech discrimination than those with a lower SDS (less than 95%). The preoperative SRT level was predictive of the timing for the requirement of hearing amplification. The postoperative SRT level was predictive of the timing for the requirement of hearing amplification. The caused by presbycusis, combined with a recurrent conductive loss in the speech frequencies rather than cochlear otosclerosis. Although the decline in hearing following stapedectomy exceeds the rate of hearing loss due to presbycusis, many individuals, after successful stapes surgery, are able to delay the need for hearing amplification for longer periods than had been previously reported.

Factors influencing hearing after stapedectomy.

Surgical results of stapes surgery have been evaluated postoperatively after 3 years, in 834 subjects with otosclerosis. The following audiological tests were used: (1) the air-bone gap; (2) pre- and postoperative speech reception thresholds (SRT); (3) postoperative SRT related to the air-bone gap; (4) the BC loss at 4000 Hz.

A Method for Predicting Postoperative Speech Reception Threshold

A Method for Predicting Postoperative Speech Reception Threshold