Is the digit triplet test an effective and acceptable way to assess speech recognition in adults using cochlear implants in a home environment?

OBJECTIVES: To evaluate the validity of the Digit Triplet Test (DTT) in a simulated home environment for measuring speech recognition in adults with cochlear implants by comparing the result to clinic speech perception tests. To evaluate the acceptability of the DTT in adults using cochlear implants. METHODS: A prospective single-centre study with the following outcomes: • DTT Speech Reception Threshold • Clinic speech perception tests (BKB sentences in quiet and noise, City University of New York sentences with lip-reading) • A satisfaction questionnaire to assess patient perception of the DTT Sixteen people using cochlear implants aged from 43 to 83 years took part. RESULTS: • Eighty-eight percent of participants were able to be tested on the DTT; there were no floor or ceiling effects. • DTT SRT was highly correlated with clinic BKB sentence scores in quiet and adaptive noise, and participants felt positive about using the DTT for home testing. CONCLUSION: The majority of adults using cochlear implants in this study were able and willing to use the DTT to test their speech recognition in a simulated home environment. The DTT SRT was highly correlated with traditional clinic sentence scores, supporting its validity as a home test for hearing in adults using cochlear implants. Hearing testing in the clinic is still the gold standard of clinical care for people with cochlear implants, but a home test could provide a useful addition.

United Kingdom national paediatric bilateral project: Results of professional rating scales and parent questionnaires.

OBJECTIVES: This fourteen-centre project used professional rating scales and parent questionnaires to assess longitudinal outcomes in a large non-selected population of children receiving simultaneous and sequential bilateral cochlear implants. METHODS: This was an observational non-randomized service evaluation. Data were collected at four time points: before bilateral cochlear implants or before the sequential implant, one year, two years, and three years after. The measures reported are Categories of Auditory Performance II (CAPII), Speech Intelligibility Rating (SIR), Bilateral Listening Skills Profile (BLSP) and Parent Outcome Profile (POP). RESULTS: Thousand and one children aged from 8 months to almost 18 years were involved, although there were many missing data. In children receiving simultaneous implants after one, two, and three years respectively, median CAP scores were 4, 5, and 6; median SIR were 1, 2, and 3. Three years after receiving simultaneous bilateral cochlear implants, 61% of children were reported to understand conversation without lip-reading and 66% had intelligible speech if the listener concentrated hard. Auditory performance and speech intelligibility were significantly better in female children than males. Parents of children using sequential implants were generally positive about their child's well-being and behaviour since receiving the second device; those who were less positive about well-being changes also generally reported their children less willing to wear the second device. CONCLUSION: Data from 78% of paediatric cochlear implant centres in the United Kingdom provide a real-world picture of outcomes of children with bilateral implants in the UK. This large reference data set can be used to identify children in the lower quartile for targeted intervention.

United Kingdom national paediatric bilateral project: Demographics and results of localization and speech perception testing.

OBJECTIVES: To assess longitudinal outcomes in a large and varied population of children receiving bilateral cochlear implants both simultaneously and sequentially. METHODS: This observational non-randomized service evaluation collected localization and speech recognition in noise data from simultaneously and sequentially implanted children at four time points: before bilateral cochlear implants or before the sequential implant, 1 year, 2 years, and 3 years after bilateral implants. No inclusion criteria were applied, so children with additional difficulties, cochleovestibular anomalies, varying educational placements, 23 different home languages, a full range of outcomes and varying device use were included. RESULTS: 1001 children were included: 465 implanted simultaneously and 536 sequentially, representing just over 50% of children receiving bilateral implants in the UK in this period. In simultaneously implanted children the median age at implant was 2.1 years; 7% were implanted at less than 1 year of age. In sequentially implanted children the interval between implants ranged from 0.1 to 14.5 years. Children with simultaneous bilateral implants localized better than those with one implant. On average children receiving a second (sequential) cochlear implant showed improvement in localization and listening in background noise after 1 year of bilateral listening. The interval between sequential implants had no effect on localization improvement although a smaller interval gave more improvement in speech recognition in noise. Children with sequential implants on average were able to use their second device to obtain spatial release from masking after 2 years of bilateral listening. Although ranges were large, bilateral cochlear implants on average offered an improvement in localization and speech perception in noise over unilateral implants. CONCLUSION: These data represent the diverse population of children with bilateral cochlear implants in the UK from 2010 to 2012. Predictions of outcomes for individual patients are not possible from these data. However, there are no indications to preclude children with long inter-implant interval having the chance of a second cochlear implant.

Brief Assessment of Parental Perception (BAPP): Development and validation of a new measure for assessing paediatric outcomes after bilateral cochlear implantation.

OBJECTIVE: In contrast to previous clinical practice, current guidelines recommend bilateral cochlear implantation in children, resulting in a cohort of children who initially received one implant, but have subsequently had a second, contralateral implant. This study aimed to explore satisfaction and quality of life in children implanted simultaneously or sequentially. DESIGN: A novel measure of satisfaction and quality of life following paediatric bilateral cochlear implantation (the Brief Assessment of Parental Perception; BAPP) was developed and preliminary validation undertaken as part of a large, national project of bilateral implantation. Children's parents completed the measure yearly for up to three years following implantation. STUDY SAMPLE: Children from 14 UK implant centres were recruited into the study; data were available for 410 children one year post-implantation. RESULTS: The BAPP was found to have good face and convergent validity, and internal consistency. Results indicated very high levels of satisfaction with the devices, and improvements in quality of life. However there was evidence that children implanted sequentially were less willing to wear their second implant in the first two years than those children receiving simultaneous implants. CONCLUSION: Simultaneous and sequential cochlear implants have a positive impact on the quality of life of deaf children.

United Kingdom national paediatric bilateral audit.

Prior to 2009, UK public funding was mainly only available for children to receive unilateral cochlear implants. In 2009, the National Institute for Health and Clinical Excellence (NICE) published guidance for cochlear implantation following their review. According to these guidelines, all suitable children are eligible to have simultaneous bilateral cochlear implants or a sequential bilateral cochlear implant if they had received the first before the guidelines were published. NICE stated that they would review this decision in 2011. In preparation for this review, 13 UK cochlear implant centres formed a consortium, and the decision was made to carry out a multi-centre audit. The audit involves collecting data from simultaneously and sequentially implanted children at three intervals: before bilateral cochlear implants or before the sequential implant, 1 year after bilateral implants, and 2 years after bilateral implants. The measures include localization, speech recognition in quiet and background noise, speech production, listening, vocabulary, parental perception, quality of life, and surgical data including complications. The audit has now passed the 1-year point, and data have been received on more than 400 children. Preliminary results will be available a year later.

Normative findings of electrically evoked compound action potential measurements using the neural response telemetry of the Nucleus CI24M cochlear implant system.

One hundred and forty-seven adult recipients of the Nucleus 24 cochlear implant system, from 13 different European countries, were tested using neural response telemetry to measure the electrically evoked compound action potential (ECAP), according to a standardised postoperative measurement procedure. Recordings were obtained in 96% of these subjects with this standardised procedure. The group results are presented in terms of peak amplitude and latency, slope of the amplitude growth function and ECAP threshold. The effects of aetiological factors and the duration of deafness on the ECAP were also studied. While large intersubject variability and intrasubject variability (across electrodes) were found, results fell within a consistent pattern and a normative range of peak amplitudes and latencies was established. The aetiological factors had little effect on the ECAP characteristics. However, age affected ECAP amplitude and slope of the amplitude growth function significantly; i.e., the amplitude is higher in the lowest age category (15-30 years). Principal component analysis of the ECAP thresholds shows that the thresholds across 5 electrodes can be described by two factors accounting for 92% of the total variance. The two factors represent the overall level of the threshold profiles ('shift') and their slopes across the electrode array ('tilt'). Correlation between these two factors and the same factors describing the T- and C-levels appeared to be moderate, in the range of 0.5-0.6.

Comparison between NRT-based MAPs and behaviourally measured MAPs at different stimulation rates--a multicentre investigation.

Seventeen adult subjects participated in a multicentre trial to compare the performance between an NRT-based MAP and their behavioural MAP. The NRT-based MAP was made using a correction factor to predict T/C levels, calculated from the difference between the ECAP threshold ('T-NRT') and the measured T/C levels at electrode 10, as described by Brown et al. (2000). A secondary aim was to compare T/C levels in behavioural MAPs at different stimulation rates with the predicted T/C levels in NRT-based MAPs. Performance with both MAPs was evaluated using CNC words and sentences. Variations in the T/C levels between all MAPs were found, although results of the speech discrimination tests demonstrated no statistically significant difference between behavioural and NRT-based MAPs.

Preliminary neural response telemetry results.

This paper describes the neural response telemetry (NRT) results obtained from the first 30 patients tested at this centre. One hundred per cent of patients tested intra-operatively had NRT responses on at least one electrode; this compared to 82.4% of patients tested post-operatively. Reasonable correlations existed between post-operative NRT thresholds and psychophysical threshold and comfort levels, although there was too much variability for the data to be used to set these parameters directly. Post-operative NRT thresholds were always at levels audible to patients.

Cochlear implantation of a deaf blind patient with mitochondrial cytopathy.

Genetic defects of the mitochondrial DNA often cause sensorineural hearing impairment, accompaniment by disorders of organs within the body. This case report describes cochlear implantation of a 33-year-old deaf blind female with mitochondrial cytopathy. The outcome was very successful, and vastly improved quality of life for this patient. Many cases of mitochondrial cytopathy cause progressive deafness; it is, therefore, likely that other patients with this unusual disorder will present for cochlear implant assessment.

Feasibility of otoacoustic emissions as a hearing screen following grommet insertion.

Following grommet insertion, it is important to establish that there is no underlying sensorineural hearing impairment. In this hospital, approximately 1000 grommet insertions are performed each year, thus generating a heavy workload of review appointments for ENT and audiology. The present study investigates the efficacy of performing evoked otoacoustic emissions screening on 108 children when they were ready to leave the hospital following grommet insertion. Bilateral normal otoacoustic emissions were recorded in 32% (35 children), although 99% (105) of the 106 children attending the outpatient review appointment had normal hearing sensitivity. If normal hearing thresholds were established immediately following surgery, it can be argued that this obviates the need for an outpatient review appointment; however, in this study only one-third of children could be discharged after surgery. Otoacoustic emissions therefore does not represent an effective screen at this stage.

Bilateral otoacoustic emissions pass in a baby with Mondini deformity and subsequently confirmed profound bilateral hearing loss.

Evoked otoacoustic emissions are well established as a hearing screening technique and are used extensively in paediatric audiology. They are believed to originate from the outer hair cells and can be detected in almost 100% of normally hearing ears; even a mild hearing loss has been shown to abolish otoacoustic emissions. Results are presented of a baby boy born at 29 weeks' gestation requiring 77 days of neonatal care, but experiencing no complications following discharge from the neonatal unit. This child had clear bilateral evoked otoacoustic emissions at almost four months of age, but was subsequently found to have a profound bilateral hearing impairment and absent otoacoustic emissions. Radiological investigations revealed bilateral Mondini dysplasia, and this child has now been implanted with a multi-channel MXM Digisonic cochlear implant. He is progressing well and shows awareness of sound. Approximately 10 previous cases of otoacoustic emissions occurring in profoundly deaf ears have been reported in the literature. Although it is likely that this child's hearing loss was progressive in nature, the authors believe that this is the first reported case of otoacoustic emissions being recorded in the presence of Mondini dysplasia. This raises concerns about the use of neonatal screening in isolation without adequate mechanisms for later identification of hearing impairment, although it is acknowledged that it represents a rare situation.

Integrity testing of cochlear implants in the awake child.

Cochlear implantation is becoming a routine rehabilitation process for profoundly deaf adults and children. Often children are implanted at just two or three years of age and therefore the subsequent tuning of the device is challenging. Although some children demonstrate quick and reliable responses to electrical stimulation, there are others who do not respond consistently thus causing concern about the functioning of the device. It is therefore desirable to have an objective test of the integrity of the implanted electrodes. The principle of the integrity test is the measurement of voltages generated by the biphasic current pulses at the electrode array; this is accomplished using surface electrodes placed around the implanted ear, in conjunction with recording and averaging equipment typically used for evoked response testing. Traditional integrity testing usually requires a general anaesthetic in young children, however this study demonstrated a simple, quick and reliable method of obtaining results in the normally active child using ear-clip electrodes. Results are presented from 12 children tested in this way, and compared with results from 20 children who were tested in theatre using a different electrode configuration. The tests were performed in common ground stimulation mode, but some measurements were also made in bipolar + 1 and pseudo-monopolar modes. The three stimulation modes were compared, with the conclusion that common ground mode provides an efficient check of implant function in the awake child, while pseudo-monopolar mode may be preferable for anaesthetized patients. In addition, measurements were made in vitro using a functioning cochlear implant in a saline tank in order to investigate the current flow during stimulation. The standard procedure in this department is to perform a full intra-operative integrity test on all implanted children. The simplified technique is used to repeat the measurement post-operatively if required.