French Society of ENT (SFORL) guidelines (short version): Audiometry in adults and children

IntroductionFrench Society of ENT (SFORL) good practice guidelines for audiometric examination in adults and children.MethodsA multidisciplinary working group performed a review of the scientific literature. Guidelines were drawn up, reviewed by an independent reading group, and finalized in a consensus meeting.ResultsAudiometry should be performed in an acoustically controlled environment (< 30 dBA); audiometer calibration should be regularly checked; and patient-specific masking rules should be systematically applied. It should be ensured that masking is not overmasking. Adult pure-tone audiometry data should be interpreted taking account of clinical data, speech audiometry and impedancemetry. In case of discrepancies between clinical and pure-tone and speech audiometry data, objective auditory tests should be perform. In children aged 2 years or younger, subjective audiometry should be associated to behavioral audiometry adapted to the child's age. In suspected hearing impairment, behavioral audiometry should be systematically supplemented by objective hearing tests to determine and confirm the level and type of hearing impairment.     

Telemedicine in Audiology. Best practice recommendations from the French Society of Audiology (SFA) and the French Society of Otorhinolaryngology-Head and Neck Surgery (SFORL)

ObjectivesAccess to diagnosis and treatments for auditory disorders and related pathologies has regressed in France during the COVID-19 pandemic, posing a risk to the patient's chance of recovery. This best practice recommendations guide aims to list the existing technological solutions for the remote examination of a patient with hearing complaint, and to outline their benefits and, where applicable, their limitations.MethodsThe recommendations were developed both from the clinical experience of the medical experts who drafted the guide, and from an extensive review of the literature dealing with clinical practice recommendations for tele-audiology. Tele-audiometry solutions were identified on the basis of a search engine query carried out in April 2020, prior to verification of their availability on the European market.ResultsVideo otoscopy solutions allow for the teletransmission of images compatible with a high-quality diagnosis, either by connecting via internet to a tele-health platform or using a smartphone or a tablet with an iOS or Android operating system. Using the same telecommunication methods, it is possible to remotely conduct a pure-tone audiometry test in accordance with standard practice, a speech-in-quiet or a speech-in-noise audiometry test, as well as objective measures of hearing. Clinical and paraclinical examinations can be accessed by the physician to be interpreted on a deferred basis (asynchronous tele-audiology). Examinations can also be conducted in real time in a patient, at any age of life, as long as a caregiver can be present during the installation of the transducers or the acoumetry. Tele-audiology solutions also find application in the remote training of future healthcare professionals involved in the management of deafness and hearing impairment.ConclusionUnder French law, tele-otoscopy is a medical procedure that is either a tele-expertise (asynchronous adive) or a teleconsultation act (synchronous advice). Subjective and objective evaluation of the patient's hearing functions can be done remotely provided that the listed precautions are respected.     

Hearing in Noise Test Brazil: standardization for young adults with normal hearing

IntroductionIndividuals with the same ability of speech recognition in quiet can have extremely different results in noisy environments.ObjectiveTo standardize speech perception in adults with normal hearing in the free field using the Brazilian Hearing in Noise Test.MethodsContemporary, cross-sectional cohort study. 79 adults with normal hearing and without cognitive impairment participated in the study. Lists of Hearing in Noise Test sentences were randomly in quiet, noise front, noise right, and noise left.ResultsThere were no significant differences between right and left ears at all frequencies tested (paired t − 1 test). Nor were significant differences observed when comparing gender and interaction between these conditions. A difference was observed among the free field positions tested, except in the situations of noise right and noise left.ConclusionResults of speech perception in adults with normal hearing in the free field during different listening situations in noise indicated poorer performance during the condition with noise and speech in front, i.e., 0°/0°. The values found in the standardization of the Hearing in Noise Test free field can be used as a reference in the development of protocols for tests of speech perception in noise, and for monitoring individuals with hearing impairment.     

Evaluation of the possible effect of magnetic resonance imaging noise on peripheral hearing organ with the otoacoustic emission

PurposeThe aim of this study is to evaluate the effect of noise produced by magnetic resonance imaging (MRI) device on hearing by using objective and subjective audiological assessments.MethodsA total of 38 patients between the ages of 18 and 50 without hearing loss, and had performed MRI for brain, head, neck or cervical imaging were included in this prospective clinical study. Pure tone audiometry, speech audiometry, high frequency audiometry, transient evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emission (DPOAE) were performed before and after MRI.ResultsThere was no statistically significant difference in TEOAE, pure tone audiogram, high frequency audiogram and speech audiogram thresholds. In DPOAE, the median value before and after MRI at the frequency of the left ear at 4.0 kHz was 13.6 (8.5–19.9) and 15.7 (8.9–20.7) SNR respectively (p > .05). The median value before MRI at the right ear 4.0 kHz frequency was 14.1 (9.1–20.5) SNR, whereas the median value after MRI was 13.2 (8.8–19.8 SNR (p = 0,03). There was no statistically significant difference in other frequencies in DPOAE.ConclusionsThis is the first objective study that examines the MRI noise on speech audiometry and otoacoustic emission together. However, the effect of MRI noise on hearing pathway is still doubt. Based on the difference at 4 kHz frequency on DPOAE; on-earphones may not sufficiently protect the patients from the MRI noise and this issue should deserve further research.     

Cochlear implant in a subject affected by the Chudley-McCullough Syndrome

Objectives: The Chudley-McCullough Syndrome (CMS) is a rare autosomal-recessively inherited disorder caused by mutations in the GPSM2 gene, characterised by deafness and brain anomalies. The purpose of this paper is to report about a case of cochlear implant (CI) procedure in a subject affected by CMS.

Methods: A 31-year-old subject affected by CMS referred to our centre requiring an evaluation for a CI, as the results with her hearing aids, which she had been using since she was 2-years-old, were unsatisfactory. A profound bilateral sensorineural hearing loss was pointed out. Pure tone audiometry in free field with hearing aids and speech perception results were poor. The subject was counselled about the surgical procedure and the surgery was performed with no complications.

Results: The cochlear implant was switched on 22 days after surgery and the subject began speech therapy training. After 1 year, hearing and speech perception results were satisfactory. The hearing threshold in free field with the CI was around 30?dB, and the open set speech perception score reached 55% in silence.

Conclusions: The reported case demonstrates that CI is a feasible and safe procedure in subjects with CMS. Furthermore, since satisfactory hearing and speech perception results were achieved we recognise that cochlear implant should be considered the best option for hearing restoration in subjects with CMS and profound sensorineural hearing loss.     

Characteristics and determinants of music appreciation in adult CI users

The main objective of this study was to assess the associations between self-reported listening habits and perception of music and speech perception outcomes in quiet and noise for both unilateral cochlear implant (CI) users and bimodal (CI in one ear, hearing aid in contra-lateral ear) users. Information concerning music appreciation was gathered by means of a newly developed questionnaire. Moreover, audiological data (pure-tone audiometry, speech tests in noise and quiet) were gathered and the relationship between speech perception and music appreciation is studied. Bimodal users enjoy listening to music more in comparison with unilateral CI users. Also, music training within rehabilitation is still uncommon, while CI recipients believe that music training might be helpful to maximize their potential with current CI technology. Music training should not be exclusively reserved for the good speech performers. Therefore, a music training program (MTP) that consists of different difficulty levels should be developed. Hopefully, early implementation of MTP in rehabilitation programs can enable adult CI users to enjoy and appreciate music and to maximize their potential with commercially available technology. Furthermore, because bimodal users consider the bimodal stimulation to be the most enjoyable way to listen to music, CI users with residual hearing in the contra-lateral ear should be encouraged to continue wearing their hearing aid in that ear.     

Audiological Evaluation of Affected Members from a Dutch DFNA8/12 (<Emphasis Type="Italic">TECTA</Emphasis>) Family

In DFNA8/12, an autosomal dominantly inherited type of nonsyndromic hearing impairment, the TECTA gene mutation causes a defect in the structure of the tectorial membrane in the inner ear. Because DFNA8/12 affects the tectorial membrane, patients with DFNA8/12 may show specific audiometric characteristics. In this study, five selected members of a Dutch DFNA8/12 family with a TECTA sensorineural hearing impairment were evaluated with pure-tone audiometry, loudness scaling, speech perception in quiet and noise, difference limen for frequency, acoustic reflexes, otoacoustic emissions, and gap detection. Four out of five subjects showed an elevation of pure-tone thresholds, acoustic reflex thresholds, and loudness discomfort levels. Loudness growth curves are parallel to those found in normal-hearing individuals. Suprathreshold measures such as difference limen for frequency modulated pure tones, gap detection, and particularly speech perception in noise are within the normal range. Distortion otoacoustic emissions are present at the higher stimulus level. These results are similar to those previously obtained from a Dutch DFNA13 family with midfrequency sensorineural hearing impairment. It seems that a defect in the tectorial membrane results primarily in an attenuation of sound, whereas suprathreshold measures, such as otoacoustic emissions and speech perception in noise, are preserved rather well. The main effect of the defects is a shift in the operation point of the outer hair cells with near intact functioning at high levels. As most test results reflect those found in middle-ear conductive loss in both families, the sensorineural hearing impairment may be characterized as a cochlear conductive hearing impairment.     

Guidelines (short version) of the French Society of Otorhinolaryngology (SFORL) on pediatric cochlear implant indications

ObjectivesThe authors present the guidelines of the French Society of Otorhinolaryngology – Head and Neck Surgery (Société française d’oto-rhino-laryngologie et de chirurgie de la face et du cou – SFORL) on the indications for cochlear implantation in children.MethodsA multidisciplinary work group was entrusted with a review of the scientific literature on the above topic. Guidelines were drawn up, based on the articles retrieved and the group members’ individual experience. They were then read over by an editorial group independent of the work group. The guidelines were graded as A, B, C or expert opinion, by decreasing level of evidence.ResultsThe SFORL recommends that children with bilateral severe/profound hearing loss be offered bilateral cochlear implantation, with surgery before 12 months of age. In sequential bilateral cochlear implantation in children with severe/profound hearing loss, it is recommended to reduce the interval between the two implants, preferably to less than 18 months. The SFORL recommends encouraging children with unilateral cochlear implants to wear contralateral hearing aids when residual hearing is present, and recommends assessing perception with hearing-in-noise tests. It is recommended that the surgical technique should try to preserve the residual functional structures of the inner ear as much as possible.     

Comparing musicians and non-musicians in signal-in-noise perception

Abstract

Objectives: The objective is to compare musicians and non-musicians in signal-in-noise perception.Design: Participants underwent the following tests: (1) High-frequency (HF) audiometry, (2) QuickSIN (a test for speech perception in noise), and (3) Binaural Masking Level Difference (BMLD) test (a test that examines the hearing threshold of a low-frequency tone from noise masking when the phase of the signal or noise in one ear is reversed with respect to the phase of the signal or noise in the other ear, i.e. the difference in the threshold for detection of the tone in noise under the S_πN_o and S_oN_o conditions).Study sample: Thirty-four healthy young normal-hearing listeners including 17 musicians (M) and 17 non-musicians (NM).Results: There were no study group difference in HF audiometry and QuickSIN. The M group had a significantly better performance under the S_oN_o but not under the S_πN_o condition. As a result, the BMLD value (S_oN_o–S_πN_o) was significantly smaller in the M group than in the NM group.Conclusions: There is a musicians’ advantage in binaural tone-in-noise detection in the BMLD task under the S_oN_o condition, suggesting that long-term music training positively shapes the auditory system.     

Phrases in noise test (PINT) Brazil: effectiveness of the test in children with hearing loss

IntroductionOne of the main implications of hearing impairment is the difficulty in perceiving speech sounds, especially in noisy environments. Thus, the frequency-modulated system is considered an important educational tool for children with hearing impairment because it improves speech perception in acoustically-unfavorable environments, such as in the classroom. The assessment of speech perception in noise is included in the verification protocol of this device.ObjectivesTo verify the effectiveness of the phrases in noise test Brazil in children with hearing impairment using an frequency-modulated system.MethodsThis was a cross-sectional cohort study. The sample included 40 children, aged 4 years to 11 years and 11 months old, divided into 4 groups: (1) 10 normal hearing children; (2) 13 children with hearing aids and frequency-modulated system; (3) 12 children using cochlear implant and fitted with the frequency-modulated system; and (4) 5 children diagnosed with auditory neuropathy spectrum disorder, fitted with hearing aids and/or cochlear implant and with the frequency-modulated system. The phrases in noise test Brazil was used to evaluate speech perception in noise under the conditions with and without the frequency-modulated system. For the statistical analysis of the data, a significance level of 5% (p < 0.05) was adopted.ResultsThere was a significant difference between the groups when they were evaluated with the frequency-modulated system. The test was also validated through concurrent and convergent validation measures. Phrases in noise test Brazil is a viable option for monitoring auditory performance in noise in different groups of children with hearing impairmen.ConclusionPhrases in noise test Brazil was effective in assessing speech perception in noise and may contribute to the improvement of the indication, fitting and follow-up protocols for the frequency-modulated system use.     

Behavioural performance and self-report measures in children with unilateral hearing loss due to congenital aural atresia

ObjectiveTo explore the behavioural and functional performance of a group of children with conductive unilateral hearing loss (UHL) due to congenital aural atresia.MethodTwelve children aged 7 to 16 years (M_age 10.0, SD 3.1 years) formed the UHL group and 15 age-matched children (M_age 9.5, SD 3.6 years) with normal hearing formed the control group. Auditory skills were assessed using tests of sound localisation, spatial speech perception in noise, and self-ratings of auditory abilities (Listening Inventory for Education; LIFE and Speech, Spatial and Qualities of Hearing scale; SSQ).ResultsWhen speech was directed to the good ear, performance was poorer than for normal hearing controls. Sound localisation abilities were impaired in children with UHL. Children with UHL reported higher levels of difficulties in classroom settings compared to children with normal hearing, particularly for activities involving listening in noise and focused listening activities. Older children self-report and parents report difficulties for their children across all SSQ scales.ConclusionsChildren with UHL showed a wide range of auditory difficulties. As expected, speech recognition in noise differed from controls. Sound localisation abilities were variable; greater variability was seen for right ear hearing losses suggesting that some of these children may have developed compensatory mechanisms. Younger children identified listening difficulties for school situations where focussed auditory attention was needed. Older children and parents reported greatest difficulty for activities requiring perception of the direction, distance, and movement of sound. Higher levels of effort and inability to ignore sounds were reported as major difficulties.     

Open fitting: performance verification of receiver in the ear and receiver in the aid

ObjectiveTo verify the receiver in the ear and receiver in the aid adaptations by measuring in situ the speech perception and users’ level of satisfaction.MethodsThe study was approved by the research ethics committee (Process: 027/2011). Twenty subjects older than 18 years with audiological diagnosis of mild and moderate bilateral descending sensorineural hearing loss were evaluated. The subjects were divided into two groups, where G1 (group 1) was fitted with open-fit hearing aids with the built-in receiver unit (receiver in the ear) and G2 (group 2) was fitted with open-fit hearing aids with RITE. A probe microphone measurement was performed to check the gain and output provided by the amplification and for assessment of speech perception with Hearing in Noise Test with and without hearing aids. After a period of six weeks of use without interruption, the subjects returned for follow-up and answered the Satisfaction with Amplification in Daily Life questionnaire, and were again subjected to Hearing in Noise Test.ResultsBoth groups presented better test results for speech recognition in the presence of noise.ConclusionGroups 1 and 2 were satisfied with the use of hearing aids and improved speech recognition in silent and noisy situations with hearing aids.     

Relative contributions of auditory and cognitive functions on speech recognition in quiet and in noise among older adults

IntroductionHearing acuity, central auditory processing and cognition contribute to the speech recognition difficulty experienced by older adults. Therefore, quantifying the contribution of these factors on speech recognition problem is important in order to formulate a holistic and effective rehabilitation.ObjectiveTo examine the relative contributions of auditory functioning and cognition status to speech recognition in quiet and in noise.MethodsWe measured speech recognition in quiet and in composite noise using the Malay Hearing in noise test on 72 native Malay speakers (60–82 years) older adults with normal to mild hearing loss. Auditory function included pure tone audiogram, gaps-in-noise, and dichotic digit tests. Cognitive function was assessed using the Malay Montreal cognitive assessment.ResultsLinear regression analyses using backward elimination technique revealed that had the better ear four frequency average (0.5–4 kHz) (4FA), high frequency average and Malay Montreal cognitive assessment attributed to speech perception in quiet (total r² = 0.499). On the other hand, high frequency average, Malay Montreal cognitive assessment and dichotic digit tests contributed significantly to speech recognition in noise (total r² = 0.307). Whereas the better ear high frequency average primarily measured the speech recognition in quiet, the speech recognition in noise was mainly measured by cognitive function.ConclusionsThese findings highlight the fact that besides hearing sensitivity, cognition plays an important role in speech recognition ability among older adults, especially in noisy environments. Therefore, in addition to hearing aids, rehabilitation, which trains cognition, may have a role in improving speech recognition in noise ability of older adults.     

Directivity and noise reduction in hearing aids: speech perception and benefit

Hearing aid.AimTo compare the performance, benefit and satisfaction of users of ITE, CIC and BTE digital hearing aid with noise reduction and omnidirectional and directional microphones.Method34 users of hearing aid were evaluated by means of speech perception in noise tests and APHAB and IOI self assessment questionnaires. Prospective study.ResultsBetter results were obtained by users of ITE, CIC and directional hearing aids, however, no statistical significance was found between the groups.ConclusionDirectivity improved speech perception in noise and benefit in daily life situations.     

Benefits of amplification for unaided speech discrimination in age-related hearing loss with flat type audiogram

ObjectiveThe present study aimed to investigate whether hearing aid use can induce improvement as acclimatization effect in unaided speech perception in patients with age-related hearing loss.MethodsFifty ears in 41 patients (age range: 65-91 years) diagnosed as age-related hearing loss were enrolled in this study. They used hearing aids for more than 8 hours per day. Unaided speech audiometry using 67-S Japanese monosyllabic word list was performed one or two years after the commencement of hearing aid use. The changes in the unaided speech discrimination score before and after the commencement of hearing aid use were analyzed. To investigate factors for improvement, the patients’ backgrounds in terms of age, sex, pure tone average, unaided maximum speech discrimination score, fitting period (one year/two years), fitting ear (bilateral/unilateral), audiogram type (flat-type/other-type), and the level of amplification were also analyzed.ResultsSignificant improvement in the unaided speech discrimination score after hearing aid use was seen only in the flat-type audiogram group. More than half of older patients in the flat-type audiogram group improved their unaided maximum speech discrimination score 10 % or more. The analysis of aided hearing thresholds revealed that the flat-type audiogram group had significantly lower thresholds of 3kHz and 4kHz than the other-type audiogram group. The age, sex, pure tone average, fitting period, fitting ear, functional gain were not influential factors for improvement. On the other hand, unaided maximum speech discrimination score before using hearing aid and aided hearing threshold at 4kHz had a negative correlation with improvement.ConclusionThe findings suggested that older patients with age-related hearing loss whose audiogram is a flat type can benefit from amplification as means of improving their unaided speech perception since flat-type audiogram can be more easily adjusted to sufficiently amplify speech sound at high frequencies. It should be considered that the potential for experience-dependent plasticity is retained even in older adults.     

The advantages of sound localization and speech perception of bilateral electric acoustic stimulation

Conclusion: Bilateral electric acoustic stimulation (EAS) effectively improved speech perception in noise and sound localization in patients with high-frequency hearing loss. Objective: To evaluate bilateral EAS efficacy of sound localization detection and speech perception in noise in two cases of high-frequency hearing loss. Methods: Two female patients, aged 38 and 45 years, respectively, received bilateral EAS sequentially. Pure-tone audiometry was performed preoperatively and postoperatively to evaluate the hearing preservation in the lower frequencies. Speech perception outcomes in quiet and noise and sound localization were assessed with unilateral and bilateral EAS. Results: Residual hearing in the lower frequencies was well preserved after insertion of a FLEX²⁴ electrode (24 mm) using the round window approach. After bilateral EAS, speech perception improved in quiet and even more so in noise. In addition, the sound localization ability of both cases with bilateral EAS improved remarkably.     

Beidohriger Zahlentest im St?rger?usch nach Sauer

Objective

For the determination of speech intelligibility in the expertise of hearing loss, the Freiburg speech test (number test and monosyllable test) is recommended in the Federal Republic of Germany. In the former German Democratic Republic, Sauer’s binaural number test with 70?dB background noise (“beidohriger Zahlentest”, BZT) was a standard element in expert opinions and was used in the calculation of bodily injury (“K?rperschaden”). In the current practice, a hearing test in noise is still lacking. The present study analyzes whether and to what degree the impairment (“Grad der Sch?digungsfolgen”, GdS) changes when also considering Sauer’s test.

Material and methods

In a collective of 78 patients with hearing loss (66 patients with high-frequency hearing loss and 12 patients with pancochlear hearing loss) and 22 normal hearing controls, the following audiometric measurements were conducted: pure tone audiometry, speech audiometry (Freiburg speech test), free field audiometry with and without noise, and Sauer’s test. Subsequently, the hearing loss for both sides was calculated taking into consideration the values obtained with and without Sauer’s test, and the respective GdS was determined.

Results

Patients with high-frequency hearing loss and pancochlear hearing loss had a trend for higher GdS (approximately 2 and 5%, respectively), compared to the established algorithm without the use of hearing tests in noise. However, neither the Mann–Whitney U-test nor the Bland–Altman analysis yielded relevant differences between the two methods to calculate the GdS.

Conclusion

The routine implementation of Sauer’s test in the expertise of hearing loss cannot be recommended, since no relevant change in the GdS can be expected. This is especially true for high-frequency hearing loss. In pancochlear hearing loss, use of Sauer’s test can be considered if problems concerning hearing in situations with background noise are present—at least until more advanced hearing tests optimized for use in noise have been integrated into the tables for GdS calculation.     

Predicting speech perception outcomes following cochlear implantation in adults with unilateral deafness or highly asymmetric hearing loss

Objective: Unilateral deafness and highly asymmetric hearing loss can impair listening abilities in everyday situations, create substantial audiological handicap, and reduce overall quality of life. Preliminary evidence suggests that cochlear implantation may be effective in reversing some of these detrimental effects. Patient-level data from existing studies were re-analysed to explore potential factors that may be predictive of improved speech perception scores following implantation.

Methods: Logistic regression modelling examined whether improved speech perception following implantation under various listening conditions was related to the duration of deafness of the severe-to-profoundly deaf ear and/or the level of hearing in the better ear.

Results: Patients with a shorter duration of deafness were more likely to improve in listening conditions that created a less favourable SNR at the implanted ear than the non-implanted ear. Those with more residual hearing in the better ear were more likely to improve in the listening condition that created a less favourable SNR at that ear.

Discussion: The analysis suggests that characteristics of both ears may be relevant when seeking to identify those candidates who are likely to obtain benefit to speech perception following cochlear implantation.     

Bone conductive implantation in asymmetric hearing loss (AHL)

Abstract

Background: Bone conductive implants (BCI) represent one possible solution for rehabilitation of single-sided deafness (SSD).

Aims: The aim of the present study was to verify the efficacy of bone conduction implantation in subjects with unilateral severe-to-profound hearing loss and contralaterally impaired hearing, that is, asymmetric hearing loss (AHL), and to compare it with known BCI indications for SSD.

Material and methods: Twenty-one subjects received BCI for either SSD or AHL. All of the subjects underwent a battery of audiological and subjective tests, Data were collected and statistically evaluated within and between the SSD group and the AHL group.

Results: A PTA threshold gain was observed in AHL patients along with improved values in speech audiometry in quiet and noise. The two visual analogue scale evaluations (QoL and QoS) and the GBI showed significantly better scores in AHL patients compared to SSD patients.

Conclusions: BCI provided improvement for auditory or speech recognition in AHL subjects, as compare to SSD. From these findings, it is possible to predict a positive role of BCI for some audiological aspects of AHL subjects that are generally not present or not detectable in SSD cases.     

Bimodal studies using adaptive dynamic range optimization (ADRO) technology

This study investigated the effects of adaptive dynamic range optimization (ADRO) processing for six bimodal listeners who used a hearing aid in one ear and a cochlear implant in the other. 'Bimodal' refers to the use of acoustic and electrical stimulation together. Bimodal speech recognition thresholds with the Japanese hearing in noise test were significantly lower for two ADRO devices than two non-ADRO devices in quiet, in noise from the front, and in noise from the implanted side. When the noise was presented from the non-implanted side there was no significant difference between the ADRO and non-ADRO conditions. The hearing aid measure of contrast questionnaire indicated that participants preferred ADRO in 77.3% of situations. ADRO was especially preferred in more difficult situations. The ADRO processing was designed for use in bimodal prostheses, and this study confirmed that speech intelligibility and sound quality improvements are obtainable by using ADRO in a bimodal context.