Telephone use and understanding in patients with cochlear implants.

Abstract

We conducted a mail survey of patients who had received cochlear implants to ascertain their ability to communicate on the telephone. Of 86 patients who responded, 38 (44 %) did not use the telephone at all, 36 (42 %) were able to use the telephone without assistance (independent users), and 12 (14%) were able to use the telephone with some type of assistance. Factors associated with independent use were male sex, older age at the onset of hearing loss, longer duration of hearing loss, successful use of hearing aids prior to cochlear implantation, implantation with a MED-EL Combi 40+ device, and a shorter duration of implant use. But regardless of circumstances, our findings suggest that many cochlear implant patients can use the telephone during daily activity without the need for assistive devices or relay services.

Introduction

Severe to profound hearing loss can limit or even preclude telephone communication, even among patients who use a hearing aid. Although studies have shown that cochlear implants have a positive effect on speech perception and speech production in such patients, (1) telephone competency is more difficult to achieve. Communication by telephone requires understanding speech without visual cues in an environment of transmission inhibitors such as distortion and noise. (2)

Studies addressing the effect of cochlear implants on telephone performance are sparse. There were, however, some investigations in the 1980s and 1990s that documented successful telephone use following implantation) s Most of these studies focused on the telephone performance of patients who used the Nucleus 22 implant (Cochlear Corp.; Lane Cove, New South Wales, Australia):

* Brown et al reported the case of an adult multichannel cochlear implant user who was able to correctly repeat 21% of the key words on the Central Institute for the Deaf (CID) Everyday Sentences Test spoken over the telephone on the first attempt. (3) When the sentences were repeated, the patient's accuracy increased to 47%.

* In a study of 28 elderly patients, Kelsall et al reported successful telephone use without the assistance of a telephone code by 6 patients (21%). (4)

* Facer et al studied telephone use in 43 postlinguistically deaf adults who had a Nucleus 22 implant and found that telephone use was possible in 33 (77%). (5) Three other patients were able to use the telephone with the assistance of a code, and I was able to use the telephone to a limited degree.

* Cohen et al selected 8 of their adult Nucleus 22 recipients who demonstrated any degree of open-set speech discrimination for evaluation. (2) Five demonstrated competency in telephone communication.

* In a study by Ito et al, 10 of 10 adult Nucleus 22 cochlear implant recipients who performed in the SPEAK coding strategy were able to easily understand natural voice conversations. (6) However, when these patients were evaluated for telephone listening ability, their performance was not satisfactory without the assistance of a telephone adapter.

* Cochlear Corp. studied long-distance telephone speech recognition in 67 postlinguistically deaf adults who used the Nucleus 24 cochlear implant. (7) Improvement over preoperative performance with hearing aids was noted in 61 patients (91%) on the CID Everyday Sentences Test and in 53 (79%) on the Psychoacoustic Laboratory Sentences Test. Median scores were 66 and 65%, respectively. Some 21% of patients recognized more than 90% of the key words during telephone tasks.

* In a study of 47 adults with a Clarion Multi-Strategy Cochlear Implant (Advanced Bionics Corp.; Sylmar, Calif.), Lalwani et al noted that two-thirds understood at least 50% of the material on the Overlearned Sentences Test transmitted via telephone. (8) Half of these patients understood at least 75% of the material.

* In a more recent study at the authors' institution, 8 postlinguistically deaf adults implanted with the MEDEL Combi 40+ device (MED-EL; Innsbruck, Austria) programmed in the CIS mode achieved a mean score of 87% on the CID Telephone Sentences Test transmitted via a standard telephone after 12 months of implant use; 5 of these patients achieved scores of 96% or higher, including 2 who achieved 100% accuracy. (9)

In this article, we describe the results of our study of telephone use among cochlear implant recipients. Our goals were (1) to identify patients at our institution who were able to use the telephone independently and examine their clinical, audiologic, and cochlear implant device characteristics and (2) to identify characteristics associated with the best performances on the CID Telephone Sentences Test.

Patients and methods

Patient selection. We accessed the patient database at the Department of Otolaryngology-Head and Neck Surgery at our institution to identify all patients who had undergone cochlear implantation between Jan. 1, 1987, and Feb. 28, 2001. All surgeries had been performed by 1 of 2 implanting surgeons during that time. All patients had been born prior to Dec. 31, 1991. Prior to testing, all patients had used their cochlear implant for at least 6 months.

Ninety-five patients met our inclusion criteria and were eligible for this study. We mailed questionnaires to all 95 patients soliciting information on telephone use, demographics, medical history (e.g., details on hearing loss and use of heating aids), and cochlear implant factors.

Data analysis. Response data were recorded and organized on a spreadsheet (Microsoft Excel 2000; Microsoft Corp.; Redmond, Wash.). Results were analyzed by SAS software version 8 (SAS Institute; Cary, N.C.).

To obtain a descriptive profile of the entire sample, responses were tabulated on the basis of sex; age at the time of the survey and at the onset of the hearing loss: the duration and etiology of the hearing loss; the duration of hearing aid use and the side amplified; self-perceived type of hearing aid user; the cochlear implant model and the side implanted; the duration of cochlear implant use; the type of speech processor that the patient preferred for general conversation and for telephone conversation; and the context in which the patient used the telephone,

A subgroup of patients was selected for further study, and data on them were collected for all of these parameters except for the type of speech processor and the context of telephone use.

Differences between groups were statistically tested according to the general linear model procedure (statistical significance: p<0.05). Our protocol was approved by our parent institution's Office of Research Subjects Protection,

Results

Survey responses. Of the 95 surveys mailed, we received responses from 86 patients (91%)--50 females (58%) and 36 males (42%).

Type of telephone use. On the basis of their self-reported telephone use, the 86 respondents were assigned to one of three groups: nonusers (n = 38 [44%]), assisted users (n = 12 [14%]), and independent users (n = 36 [42%]). Nonusers were defined as patients who engaged in no direct verbal telephone use. Assisted users were defined as those who were able to use the telephone with the assistance of an adapter. Independent users were those who were able to communicate on standard and cellular telephones without assistance.

Sex. Most males (57%) were nonusers, while a plurality of females (48%) were independent users.

Age at the time of the survey. Patients' ages at the time of the survey ranged 10 to 88 years (nonuser mean: 45.9; assisted user mean: 25.5; independent user mean: 29.2). Independent use was reported by 20 of 30 pediatric (age: <18 yr) patients (67%), but by only 16 of 56 adults (29%).

Age at the onset of hearing loss. Patients' ages at the onset of hearing loss ranged from birth to 67 years (nonuser mean: 21 yr; assisted user mean: 27; independent user mean: 9.7).

Duration of hearing loss. The duration of hearing loss ranged from 1 to 62 years (nonuser mean: 25; assisted user mean: 27; independent user mean: 19).

Etiology of hearing loss. Various etiologies of hearing loss were represented across all groups (table).

Duration of hearing aid use, The duration of hearing aid use prior to cochlear implantation ranged from 1 to 58 years and was similar across the three groups. One independent user reported no hearing aid use, but in fact this patient had been fitted with clinic-loaned heating aids 6 months prior to implantation.

Side of amplification. Preoperatively, most patients had used binaural amplification systems (68% of nonusers; 75% of assisted users; 81% of independent users).

Self-perceived type of hearing aid user. Although all patients met standard clinical and audiologic criteria for cochlear implantation (e.g., severe to profound bilateral sensorineural hearing loss), 35 of the 38 nonusers (92%) regarded themselves as fair or poor hearing aid users prior to implant placement; in contrast, 26 of 35 independent users (74%) rated themselves as excellent or good hearing aid users before implant placement. Nine of the 12 assisted users (75%) considered themselves good or fair hearing aid users before receiving their cochlear implants.

Cochlear implant model. Sixty-five patients (76%) had received the Nucleus 22 cochlear implant system (32 nonusers [49%]; 12 assisted users [18%]; 21 independent users [32%]). Eleven patients (13%) had received the MED-EL Combi 40+ implant (all were independent users), Eight patients (9%) had received the Nucleus 24 cochlear implant patients (4 nonusers and 4 independent users). Two patients (2%) had received the Clarion S implant (both were nonusers).

Side of implantation. The right ear had been implanted in 56 of the 86 patients (65%); the right was the most common side in all three groups.

Duration of implant use. The duration of cochlear implant use ranged from 6 months to 14 years (nonuser mean: 6.1 yr; assisted user mean: 7.4; independent user mean: 4.7).

Type of speech processor. Some 29 of 38 nonusers (76%) and 10 of 12 assisted users (83%) preferred the body-worn model of speech processor for natural voice communication; 21 of the 36 independent users (58%) preferred the ear-level processor. For telephone communication, however, only 14 of the 36 independent users (39%) preferred the ear-level processor; 15 independent users (42%) preferred the body-worn processor for telephone communication, and 7 (19%) used both.

Context of telephone use. Of the 48 patients who were either assisted users or independent users, 26 (54%) said they used the telephone to conduct daily affairs, and 47 (98%) used the telephone for social conversations. Eighteen of these patients (38%) were employed, including 10 who used the telephone on the job.

Study of independent users. Of the 36 independent users, 34--21 females and 13 males, aged 10 to 71 years--accepted our invitation to participate in a telephone listening task. Each patient was placed in a room with a standard land-line telephone and given instructions by a member of the study team. The participant was asked to repeat sentences presented from two randomly selected lists that make up the CID Telephone Sentences Test. The sentences were spoken by another study team member from a remote telephone elsewhere in the hospital.

Responses were scored, averaged for the two lists, and ranked according to performance. An average score of 90 to 100% was designated as a very good performance, an average of 80 to 89% was classified as good, and the rest were classified as fair. In order to ensure consistency, the same speaker, room, and telephones were used during all tests.

Test results. The mean score of the group as a whole was 67%. Nine patients (26%) were classified as very good (mean age: 38.4), 4 (12%) as good (mean age: 29.8), and 21 (62%) as fair (mean age: 23.5).

Sex. Group analysis based on sex revealed that males achieved a better performance than females. Nine of the 13 males (69%) achieved either very good or good performances, while 17 of the 21 females (81%) registered only a fair score.

Age at the time of the survey. Adults fared better than children. Eight of the 14 adults (57%) were classified as either very good or good, whereas 15 of the 20 children (75%) were classified as fair.

Age at the onset of hearing loss. Patients' ages at the time of hearing loss ranged from 0 to 47 years (very good mean: 13.5; good mean: 9.7; fair mean: 6.7).

Duration of hearing loss. The duration of heating loss ranged from 3 to 59 years (very good mean: 24.9; good mean: 19.9;fair mean: 16.8).

Etiology of the hearing loss. No trends in etiology were evident among the three groups.

Duration of hearing aid use. The duration of hearing aid use ranged from 0 to 38 years (very good mean: 14,7; good mean: 15.5;fair mean: 9.7).

Side of amplification. Twenty-nine of the 34 patients (85%) used binaural amplification prior to surgery.

Self-perceived type of hearing aid user Among the 13 patients in the very good and good groups combined, 11 (85%) described themselves as excellent or good hearing aid users prior to implantation, as did 14 of 20 (70%) in the fair group (1 fair patient did not answer this question). The correlation between performance score and self-perceived type of hearing aid user was statistically significant (p<0.0181).

Type of cochlear implant. The Nucleus 22 implant was used by 20 patients, the MED-EL Combi 40+ implant by 12 patients, and the Nucleus 24 implant by 2 patients. Among the Nucleus 22 implant users, 4 were in the combined very good/good group and 16 were in the fair group. Among the MED-EL Combi 40+ implant users, 9 were in the very good/good group and 3 were in the fair group. Both patients who used the Nucleus 24 implant were in the fair group.

Side of implantation, Right-side implants were reported by 22 of the 34 patients (65%).

Duration of implantation, The duration of cochlear implant use ranged from 6 months to 14 years and tended to be shorter in patients with better performances (very good mean: 2.2 yr; good mean: 5.5;fair mean: 5.9).

Discussion

Our results support the findings of earlier studies that telephone communication is possible for many cochlear implant patients. The percentage of patients in our study who were independent users (42%) is comparable with percentages reported in previous studies. (4,5)

We also found a wide range in the degree of telephone sentence understanding as measured by the CID Telephone Sentences Test among the independent users. It is noteworthy that a poor performance on this test did not preclude telephone use, since 8 of the 34 independent users (24%) scored less than 50%. It is likely that other factors, such as familiarity with speakers and topics, play a role in successful telephone communication, The importance of familiar aspects is supported by the observation that the telephone was used more for social purposes than for conducting daily affairs or for job-related purposes.

One factor that was highly relevant to better telephone performance was the patients' self-assessment of the quality of their hearing aid use prior to implantation. Although all 86 patients "failed" the preoperative audiologic test protocol and met other criteria necessary for cochlear implantation, 34 (40%) still viewed their experience with hearing aids as beneficial. We speculate that such favorable self-assessments are a function of a motivated personality, and motivation has been found to play an important role in achieving telephone competance. (2) In addition, Aronson et al studied the use of routine telephone training in aural habilitation of a pediatric population. (10) They found that this type of intervention might be successful among patients who are relatively less motivated to acquire telephone skills on their own.

Another factor associated with better telephone performance was the type of cochlear implant itself. Patients who used the MED-EL Combi 40+ implant performed at a superior level. However, we must acknowledge that our study is limited to some degree by the small number of patients in the independent user group (n = 36). In addition, there was suboptimal representation of all currently available devices. For example, the Clarion implant was used in only 2 of our 86 patients (2%). Many of our institution's Clarion patients either did not return their survey or did not meet our inclusion criteria.

Other trends are worthy of comment. Among the 86 patients, independent use was reported by a higher percentage of pediatric patients than adults. However, among these independent users, the adults achieved higher overall scores on the CID Telephone Sentences Test. A similar pattern was noted in the analysis of patient sex. Although the females had a higher prevalence of independent use, they had lower test scores.

Although the duration of hearing loss was not a statistically significant factor in CID Telephone Sentences Test scores (p<0.08), the very good group was well represented by patients with longer durations of hearing loss. This observation contradicts findings reported by Lalwani et al, who indicated that patients whose performances were poor had longer durations of hearing loss. (8)

It is interesting that independent users tended to have a shorter duration of cochlear implant use than nonusers and assisted users. So did those with higher CID Telephone Sentences Test scores. We hypothesize that the reason for this is that the newer devices offer improved technology and programming options.

We also noted that the independent users who had Nucleus 22 implants preferred to use their ear-level units for general communication and their body-level processors for telephone communication. The MED-EL Combi 40+ patients indicated that overall performance was better with their Tempo+ ear-level models.

Our findings suggest that many cochlear implant patients can use the telephone during daily activity without the need for assistive devices or relay services. According to our study, a typical good performer is an adult male who was relatively older when he lost his hearing but who has already experienced a relatively longer duration of hearing loss; he had previously worn a high-quality hearing aid, and he received a MED-EL Combi 40+ implant a relatively short time ago.

Table. Etiology of hearing loss in 86 patients

Etiology                             n  (%)

Unknown cause (progressive)          25 (29.1)
Unknown cause (congenital)           18 (20.9)
Meningitis                           14 (16.3)
Heredity                              4 (4.7)
Immune system disorder                4 (4.7)
Ototoxicity                           4 (4.7)
Mondini's malformation                3 (3.5)
Otosclerosis                          3 (3.5)
Idiopathic cause (sudden)             2 (2.3)
Excessive noise                       2 (2.3)
Electrocution                         1 (1.2)
Kawasaki's disease                    1 (1.2)
Measles                               1 (1.2)
Meniere's disease                     1 (1.2)
Trauma                                1 (1.2)
Usher's syndrome                      1 (1.2)
Waardenburg's syndrome                1 (1.2)

Acknowledgment

We acknowledge Cindy Cors of the Department of Biostatistics at the Virginia Commonwealth University Health Systems for her assistance with the data analysis.

References

(1.) Cochlear Implants in Adults and Children. NIH Consensus Statement. 1995 May 15-17;13(2):1-30.

(2.) Cohen NL, Waltzman SB, Shapiro WH, Telephone speech comprehension with use of the Nucleus cochlear implant, Ann Otol Rhinol Laryngol Suppl 1989;142:8-11.

(3.) Brown AM, Clark GM, Dowell RC, et al. Telephone use by a multi-channel cochlear implant patient. An evaluation using open-set CID sentences. J Laryngol Otol 1985;99:231-8,

(4.) Kelsall DC, Shallop JK, Burnelli T. Cochlear implantation in the elderly. Am J Otol 1995;16:609-15.

(5.) Facer GW, Peterson A, Brey RH, et el. The Mayo Clinic experience with the cochlear implant. Ear Nose Throat J 1994;73:149-52, 154-5.

(6.) Ito J, Nakatake M, Fujita S. Hearing ability by telephone of patients with cochlear implants. Otolaryngol Head Neck Surg 1999;121:802-4.

(7.) Package insert, Nucleus 24 cochlear implant system, Cochlear Corp., Lane Cove, New South Wales, Australia.

(8.) Lalwani AK, Larky JB, Wareing MJ, et el. The Clarion Multi-Strategy Cochlear Implant--surgical technique, complications, and results: A single institutional experience. Am J Otol 1998; 19:66-70,

(9.) Hasenstab MS, Farmer TL, Kastetter SK, White J. Telephone understanding of MED-EL cochlear implant patients, Presented at the Cochlear Implant Conference; Feb, 28 to March 4, 2001: Los Angeles.

(10.) Aronson L, Estienne P, Arauz SL, Pallante SA, Telephone speech comprehension in children with multichannel cochlear implants, Am J Otol 1997:18(Suppl):S151.2.

From the Department of Otolaryngology-Head and Neck Surgery (Dr. Adams, Dr. Pippin, and Dr. Sismanis) and the Audiology Center (Dr. Hasenstab), Virginia Commonwealth University Health Systems, Medical College of Virginia Hospitals and Physicians, Richmond.

Reprint requests: Dr. M. Suzanne Hasenstab, Virginia Commonwealth University Health Systems, Medical College of Virginia Hospitals and Physicians, PO Box 980150, Richmond, VA 23298-0150. Phone: [phone]; fax [phone]; e-mail: [e-mail]

Originally presented at the scientific sessions of the Combined Otolaryngological Spring Meetings; May 11,2002; Boca Raton, Fla.