Effects of fexofenadine, diphenhydramine, and alcohol on driving performance. A randomized, placebo-controlled trial in the Iowa driving simulator.

BACKGROUND: Sedating antihistamines may impair driving performance as seriously as alcohol. OBJECTIVE: To compare the effects of fexofenadine, diphenhydramine, alcohol, and placebo on driving performance. DESIGN: Randomized, double-blind, double-dummy, four-treatment, four-period crossover trial. SETTING: The Iowa Driving Simulator. PARTICIPANTS: 40 licensed drivers with seasonal allergic rhinitis who were 25 to 44 years of age. INTERVENTION: One dose of fexofenadine (60 mg), diphenhydramine (50 mg), alcohol (approximately 0.1% blood alcohol concentration), or placebo, given at weekly intervals before participants drove for 1 hour in the Iowa Driving Simulator. MEASUREMENTS: The primary end point was coherence, a continuous measure of participants' ability to match the varying speed of a vehicle that they were following. Secondary end points were drowsiness and other driving measures, including lane keeping and response to a vehicle that unexpectedly blocked the lane ahead. RESULTS: Participants had significantly better coherence after taking alcohol or fexofenadine than after taking diphenhydramine. Lane keeping (steering instability and crossing the center line) was impaired after alcohol and diphenhydramine use compared with fexofenadine use. Mean response time to the blocking vehicle was slowest after alcohol use (2.21 seconds) compared with fexofenadine use (1.95 seconds). Self-reported drowsiness did not predict lack of coherence and was weakly associated with minimum following distance, steering instability, and leftlane excursion. CONCLUSIONS: Participants had similar performance when treated with fexofenadine or placebo. After alcohol use, participants performed the primary task well but not the secondary tasks; as a result, overall driving performance was poorer. After participants took diphenhydramine, driving performance was poorest, indicating that diphenhydramine had a greater impact on driving than alcohol did. Drowsiness ratings were not a good predictor of impairment, suggesting that drivers cannot use drowsiness to indicate when they should not drive.

Surgical management of Bell's palsy.

OBJECTIVES: Incomplete return of facial motor function and synkinesis continue to be long-term sequelae in some patients with Bell's palsy. The aim of this report is to describe a prospective study in which a well-defined surgical decompression of the facial nerve was performed in a population of patients with Bell's palsy who exhibit the electrophysiologic features associated with poor outcomes. In addition, management issues related to Bell's palsy including herpes simplex virus typel etiology, the natural history, electrodiagnostic testing, and efficacy of surgical strategies are reviewed. STUDY DESIGN AND METHODS: A multicenter prospective clinical trial was designed utilizing electroneurography (ENOG) and voluntary electromyography (EMG) to identify patients with Bell's palsy who would most likely develop poor return of facial function, as suggested by Fisch and Esslen. Patients who displayed electrodiagnostic features of poor outcome, >90% degeneration on ENOG testing and no voluntary motor unit EMG potentials within 14 days of onset of total paralysis, were offered a surgical decompression of the facial nerve through a middle cranial fossa surgical exposure, including the tympanic segment, geniculate ganglion, labyrinthine segment, and meatal foramen. Control subjects were those who displayed similar electrodiagnostic features and time course. RESULTS: Subjects who did not reach 90% degeneration on ENOG within 14 days of paralysis all returned to House-Brackmann grade I (n = 48) or II (n = 6) at 7 months after onset of the paralysis. Control subjects self-selecting not to undergo surgical decompression when >90% degeneration on ENOG and no motor unit potentials on EMG were identified had a 58% chance of developing a poor outcome at 7 months after onset of paralysis (House-Brackmann grade III or IV [n = 19]). A group with similar ENOG and EMG findings undergoing middle fossa facial nerve decompression exhibited House-Brackmann grade I (n = 14) or II (n = 17) in 91% of the cases. An exact permutation test confirmed that the surgical group had a significantly higher proportion of patients with a good outcome (House-Brackmann grade I or II) (P = .0002). CONCLUSION: Electroneurography in combination with voluntary EMG successfully identified patients who will most likely return to normal from those who had a greater chance of long-term sequelae from Bell's palsy. Surgical decompression medial to the geniculate ganglion significantly improves the chances of normal or near-normal return of facial function in the group that has a high probability of a poor result. Surgical decompression must be performed within 2 weeks of onset of total paralysis for it to be effective.

Carrier rates in the midwestern United States for GJB2 mutations causing inherited deafness.

CONTEXT: Mutations in the GJB2 gene are the most common known cause of inherited congenital severe-to-profound deafness. The carrier frequency of these mutations is not known. OBJECTIVES: To determine the carrier rate of deafness-causing mutations in GJB2 in the midwestern United States and the prevalence of these mutations in persons with congenital sensorineural hearing loss ranging in severity from moderate to profound, and to derive revised data for counseling purposes. DESIGN: Laboratory analysis, performed in 1998, of samples from probands with hearing loss for mutations in GJB2 using an allele-specific polymerase chain reaction assay, single-strand conformation polymorphism analysis, and direct sequencing. SETTING AND SUBJECTS: Fifty-two subjects younger than 19 years sequentially referred to a midwestern tertiary referral center for hearing loss or cochlear implantation, with moderate-to-profound congenital hearing loss of unknown cause, parental nonconsanguinity, and nonsyndromic deafness with hearing loss limited to a single generation; 560 control neonates were screened for the 35delG mutation. MAIN OUTCOME MEASURE: Prevalence of mutations in the GJB2 gene by congenital deafness status. RESULTS: Of 52 sequential probands referred for congenital sensorineural hearing loss, 22 (42%) were found to have GJB2 mutations. The 35delG mutation was identified in 29 of the 41 mutant alleles. Of probands' sibs, all homozygotes and compound heterozygotes had deafness. Fourteen of 560 controls were 35delG heterozygotes, for a carrier rate expressed as a mean (SE) of 2.5% (0.66%). The carrier rate for all recessive deafness-causing GJB2 mutations was determined to be 3.01% (probable range, 2.54%-3.56%). Calculated sensitivity and specificity for a screening test based on 35delG mutation alone were 96.9% and 97.4%, respectively, and observed values were 94% and 97%, respectively. CONCLUSIONS: Our data suggest that mutations in GJB2 are the leading cause of moderate-to-profound congenital inherited deafness in the midwestern United States. Screening of the GJB2 mutation can be offered to individuals with congenital deafness with high sensitivity and specificity by screening only for the 35delG mutation. A positive finding should establish an etiologic diagnosis and affect genetic counseling.

Performance of 2- and 3-year-old children and prediction of 4-year from 1-year performance.

OBJECTIVE: To examine whether children perform better when they receive cochlear implants when they are 2 to 4 years of age than when they are older, and to determine whether 4-year performance can be predicted from 1-year results. METHOD: Children in two age groups (2 to 4, 4 to 9 years) were tested for performance, and the age groups were compared. Children were also tested 1 and 4 years after implantation. RESULTS: The results suggest that the "implanted young" group scored higher than the "implanted old" group after 36 months, and that 1-year performance is helpful in predicting 4-year performance. CONCLUSION: It may be desirable for children to undergo implantation when they are under 2 years of age, provided that appropriate selection criteria can be determined.

Performance over time of adult patients using the Ineraid or nucleus cochlear implant.

This study examined the average and individual performance over time of 49 adult cochlear implant subjects. Subjects were randomly assigned to receive either the Ineraid cochlear implant, with analog processing, or the Nucleus cochlear implant, with feature-extraction processing. All subjects had postlingual profound bilateral sensorineural hearing loss and received no significant benefit from hearing aids before implantation. Group data were examined in two ways. First, only subjects who had complete data over the test period were examined. Second, an analysis of all available data was carried out by mixed linear-model analysis. In this analysis, to account for missed follow-ups at the planned intervals, data consisting of the observations closest in time to the planned test times were modeled by natural splines with knots at the planned follow-up times. Contrasts between all pairs of planned follow-up times for each device were tested, as were contrasts between devices at each planned follow-up time. Results indicated little difference between the performance of the Ineraid and Nucleus subjects in their level of performance or their rate of learning. Postimplantation performance was typically superior to preimplantation performance within 9 months, and continued to improve up to 18-30 months depending on the speech perception measure. In some subjects, improvements in speech perception measures were observed up to four or five years postimplantation. There was also evidence that three subjects had a decrement in overall speech perception performance, although their postimplantation scores were always higher than their preimplantation scores. In at least one subjects this was likely a result of age-related cognition decrements.

Cochlear implant use by prelingually deafened children: the influences of age at implant and length of device use.

This study focused on long-term speech perception performances of 34 prelingually deafened children who received multichannel cochlear implants manufactured by Cochlear Corporation. The children were grouped by the age at which they received cochlear implants and were characterized by the amount of time they used their device per day. A variety of speech perception tests were administered to the children at annual intervals following the connection of the external implant hardware. No significant differences in performance are evident for children implanted before age 5 compared to children implanted after age 5 on closed-set tests of speech perception ability. All children demonstrated an improvement in performance compared to the pre-operative condition. Open-set word recognition performance is significantly better for children implanted before age 5 compared to children implanted after age 5 at the 36-month test interval and the 48-month test interval. User status, defined by the amount of daily use of the implant, significantly affects all measures of speech perception performance except pattern perception.

Initial independent results with the Clarion cochlear implant.

OBJECTIVE: This paper reports some preliminary findings from patients, implanted at the University of Iowa, using the Advanced Bionics Clarion cochlear implant (version 1.0). We compared the performance of patients using both simultaneous analog and nonsimultaneous pulsatile processing strategies. The performance of Clarion patients was also compared with a group of patients who were using either the feature-extraction Nucleus cochlear implant or the compressed-analog Ineraid cochlear implant. DESIGN: One aim was to compare the analog and pulsatile stimulation in 19 patients using the Clarion implant. This aim could be accomplished only partially because of difficulties encountered in adequately fitting patients with the analog strategy. A second aim was to compare the Clarion users' performance with feature-extraction Nucleus and compressed-analog Ineraid patients. Comparisons were made with all patients having 9 mo experience postimplantation. RESULTS: Subjects performed better using the pulsatile mode compared with the analog mode. All subjects chose to use the pulsatile strategy after the first 3 mo of the study. Results comparing performance at 9 mo with our compressed-analog Ineraid and feature-extraction Nucleus patients indicated, in general, better average performance for the Clarion users. CONCLUSIONS: We conclude that the pulsatile version of the Clarion cochlear implant typically produces superior performance to the analog version of that device at this stage in its development. After 9 mo of experience, users of the Clarion implant are performing better than are users of the feature-extraction Nucleus and compressed-analog Ineraid cochlear implants with comparable amounts of experience.

A within-subject comparison of adult patients using the Nucleus F0F1F2 and F0F1F2B3B4B5 speech processing strategies.

This study compares the Nucleus F0F1F2 and F0F1F2B3B4B5 (also known as "Multipeak") of "Mpeak") processing schemes in 17 patients wearing the Mini Speech Processor. All patients had at least 18 months implant experience using the F0F1F2 processing strategy. For this study, they were switched to the F0F1F2B3B4B5 processing strategy for 3 months. They then returned to using the F0F1F2 strategy for 3 months, then used the F0F1F2B3B4B5 strategy again for 3 months, and lastly used the F0F1F2 strategy for 3 months. Performance' was evaluated with both schemes after each interval, using speech recognition tests and subjective ratings. Overall, differences between the results for the two processing schemes were not large. Average performance was somewhat better for the F0F1F2B3B4B5 strategy for word and sentence identification, but not for any of the other speech measures. Superior performance was observed in 8 patients with the F0F1F2B3B4B5 strategy. However, 6 of the 8 individuals were significantly better on only one of the six speech measures in the test battery. The other 2 patients performed better on two of the speech measures. Superior performance was also observed in 3 patients with F0F1F2 strategy for consonant recognition. For the remaining patients, there was little difference in their performance with the two strategies. Information transmission analyses indicated that the F0F1F2B3B4B5 strategy transmitted consonant duration and frication cues more efficiently than F0F1F2. Experience with one strategy appeared to benefit performance with the other strategy.

Performance of adult Ineraid and Nucleus cochlear implant patients after 3.5 years of use.

Forty-two postlingually deafened adult patients, 21 with a formant extraction version of the Nucleus cochlear implant and 21 with the Ineraid cochlear implant (analog processing), were evaluated on a series of speech perception tests after using their implants for about 3.5 years. A wide range of performance was observed across patients for both devices. All but 4 patients showed an enhancement in their lipreading ability with the implant. Word recognition averaged about 14-19% correct, and word recognition in sentences averaged about 43-49% correct for the two implant groups. Average performance was superior with the Ineraid implant on consonant recognition in noise. An information transmission analysis suggested that vowel perception was influenced by first- and third-formant frequency for the Nucleus, and first-formant and fundamental frequency for the Ineraid patients. It appeared that the Ineraid device was more effective, on average, at conveying information about consonant nasality and frication. For consonant perception, nasality and frication contributed most to the total information transmitted for both implant types. Both devices had difficulty conveying information about vowel second-formant frequency and consonant place information. These scores at 3.5 years are substantially elevated from preoperative performance and, overall, the patients clearly benefit from their implant.

Acquisition of speech by children who have prolonged cochlear implant experience.

The four purposes of this investigation were to assess whether children acquire intelligible speech following prolonged cochlear-implant experience and examine their speech error patterns, to examine how age at implantation influences speech acquisition, to assess how speech production and speech perception skills relate, and to determine whether cochlear implant recipients who formerly used simultaneous communication (speech and manually coded English) begin to use speech without sign to communicate. Twenty-eight prelinguistically deafened children who use a Nucleus cochlear implant were assigned to one of three age groups, according to age at implantation: 2-5 yrs (N = 12), 5-8 yrs (N = 9), and 8-15 yrs (N = 7). All subjects had worm a cochlear implant for at least 24 mos, and an average of 36 mos. All subjects used simultaneous communication at the time of implantation. Subjects performed both imitative and structured spontaneous sampling speech tasks. The results permit the following conclusions: (a) children who have used a cochlear implant for at least 2 yrs acquire some intelligible speech; (b) children who receive a cochlear implant before the age of 5 yrs appear to show greater benefit in their speech production skills than children who are older, at least after a minimum of 2 yrs of use; (c) children who recognize more speech while wearing their cochlear implants are likely to speak more intelligibly; and, (d) signing does not disappear from a child's communication mode following implantation.

Deriving passage difficulties for a tracking study via the Cloze technique.

The current report demonstrates the importance of formally accounting for passage difficulty when using the tracking procedure. Cloze responses to 82 encyclopedia excerpts (343-349 words each) were obtained from a large pool of normal-hearing adults and scored verbatim. Passage difficulty, derived via ANOVA, was then defined as the deviation of a passage's mean Cloze score from the score for all passages, corrected for differences among respondents. The passage difficulties were applied in an alternating conditions tracking experiment with one adult cochlear implant user. Conditions included conventional auditory-visual and auditory-only tracking and experimental mode-switching techniques in which the talker changed modalities during the correction phase. An ANCOVA of the word-per-minute scores was conducted, with passage difficulty as a covariate and passage adjustment values as the output. Tracking rates and percentage of words correct from the beginning and end of training were examined. Use of adjusted data reversed the interpretation of performance change, demonstrating the need for determining passage difficulties a priori.

Results of multichannel cochlear implants in congenital and acquired prelingual deafness in children: five-year follow-up.

Postlingually deafened children, using multichannel cochlear implants, have achieved substantial improvement in their speech perception abilities and, in many instances, the results are better than in postlingually deafened adults. It has been suggested that children with prelingually acquired and congenital deafness would not receive similar benefits, since they have not developed an auditory memory. The purpose of this study is to analyze the speech perception and production performance over time of prelingually deafened children who have been using a multichannel cochlear implant for 1-5 years. Preliminary results comparing the effects of age at implantation and etiology of deafness on performance are also examined.

Analysis of longitudinal data with unequally spaced observations and time-dependent correlated errors.

A linear model for repeated measurements is proposed in which the correlation structure includes a transformation of the time scale. This transformation can produce nonstationary covariance structures within subjects with stationarity as a special case. Restricted maximum likelihood methods for parameter estimation are discussed. The method is applied to simulated data as well as speech recognition data from the Iowa Cochlear Implant Project. The growth curve for this audiologic performance measure is shown together with estimates of the standard errors of predictions at given months.

Slope estimation in the presence of informative right censoring: modeling the number of observations as a geometric random variable.

A method is proposed for the estimation of rate of change from incomplete longitudinal data where the number of observations made for each subject is assumed to vary depending on the level of the response variable. The proposed method involves a random slope model, in which the number of observations is modeled as a geometric distribution with its mean dependent on the individual subject's rate of change. The method adjusts for informative right censoring and provides estimates of the slopes of individual subjects as well as of the population. Under noninformative right censoring these estimators of the slopes are equivalent to Bayes estimators (Fearn, 1975, Biometrika 62, 89-100). The simulation study demonstrates that, in cases where the censoring process is informative, the proposed estimator is more efficient than either the unweighted or weighted estimator of slope. The method is illustrated by the analysis of renal transplant data.

Multivariate predictors of audiological success with multichannel cochlear implants.

To predict the audiological outcomes of 2 multichannel cochlear implants, a preoperative battery of historical, audiological, electrophysiologic, and psychologic variables from 48 postlingually deafened adults was tested in a prospective randomized clinical trial. Multivariate analyses were used to select and combine these preoperative variables in a predictive index that was significantly related to audiological outcome at 9 months. The preoperative variables included in the predictive index were duration of profound deafness, speech reading ability, residual hearing, cognitive ability, measures of compliance and engagement with treatment, and use of nonverbal communication strategies. The preoperative predictive index had correlations of .81 with the Iowa Sentences Test, and .78 with the NU-6 word understanding scores, both obtained in a sound-only test. Probability and percentile curves generated from these data offer considerable optimism in forecasting the range of likely audiological outcomes that would be realized by postlingually deafened adult candidates for multichannel cochlear implants.

Performance over time with a nucleus or Ineraid cochlear implant.

This investigation determined whether the audiological performance of cochlear implant users varied with experience. Thirteen Nucleus and 14 Ineraid subjects were evaluated at 1, 9, and 18 mo after cochlear implant connection. Ten Nucleus and five Ineraid subjects were tested at 30 mo. On average, the ability of the subjects to recognize words and phonemes in an audition-only condition improved during the first 9 mo, as did their ability to recognize spondees in noise. The phoneme scores continued to improve during the next 9 mo. Environmental sound recognition improved gradually; significant improvement from the 1 mo scores was not noted until 18 mo. About half of the subjects who demonstrated poor word recognition at 1 mo showed significantly improved percent word correct scores by 18 mo. The Nucleus and Ineraid subjects did not differ in their patterns of change over time. An information transmission analysis performed on the subjects' consonant confusion matrices showed relatively little change for the nasality and place features during the first 18 mo, and relatively large change for the voice, duration, and frication features. Most improvement in the feature scores occurred during the first 9 mo.