Speech Comprehension Test Research Articles

Relationship between speech intelligibility and comprehension in the presence of poor acoustics and poor voice quality

Noisy classrooms with poor acoustics decrease children’s speech understanding and comprehension. The signal quality is also often degraded by voice disorders that have a prevalence of 60% among teachers. Emerging evidence demonstrates that cognitive factors such as working memory (WM), attention, and inhibitory control (IC) also mediate children’s ability to recognize speech in noise. Speech intelligibility and comprehension tests were performed in a sound-proof booth with xx normal-hearing elementary students. The vocal material was recorded by an actor with normal and mimicked dysphonic voice. Babble noise was added to obtain 2 signal-to-noise (SNR) ratios at 0 and −12 dB. The test was administered using Qualtrics to collect intelligibility and comprehension scores, and measure response time to evaluate listening effort. Children’s WM and IC were also evaluated to explain individual differences. Results showed a statistically significant decrease in performance and increase in response time for the highest SNR and the dysphonic voice with a more detrimental effect on comprehension. This research determined how listening comprehension interacts with speech recognition and cognitive factors in children, providing pilot data to examine the variability of students' learning experience in classrooms when auditory input is degraded by poor acoustics and poor voice quality.

A functional test for hearing aids outcomes assessment

We present a functional test for speech understanding called hearing aids (HAs) objective outcomes – HO2 (pronounced as /hɑ:t/) app. It uses natural speech stimuli and generates word level accuracies, phonetic, and broad-phonetic confusion matrices. In the current best practices, hearing loss (HL) is diagnosed using pure tone audiometry (PTA). While PTA is also a functional test, it characterizes only sound detection ability of discrete pure tones, but not overall speech intelligibility due to cochlear impairments leading to sensorineural hearing loss. HO2 app stimuli are based on minimal contrast sets (MCS) of words in a given language. Each word within a subgroup of MCS words differ in a minimal set of (acoustic) phonetic features resulting in a different meaning—phonemics of the given language. The tool includes configuration parameters to include video and closed captions to minimize the role of higher level (cortical) language processes. Researchers can save HO2 app experimental conditions in a configuration file and share with others for repeatability and reproducibility. We present the feasibility of normal and hearing-impaired subjects (mild and moderate HL) to self-administer speech comprehension tests in multiple listening conditions using HO2 app. For the hearing-impaired subjects, results in unaided and aided conditions are presented.

Subjective Voice Handicap and Vocal Tract Discomfort in Patients With Cochlear Implant

Changes in the auditory system, for example due to hearing impairment, can cause changes in breathing, phonation, and articulation. Aim of this study was to provide first data on subjective Voice Handicap and Vocal Tract Discomfort in subjects with hearing impairment and cochlear implant (CI) after initial fitting. Prospective cross-sectional study METHODS: A total of 111 participants (57 female and 54 male) between 20 and 85 years of age (mean=58.21, SD=14.96) were recruited between October 2019 and March 2020 from the Clinic of Otorhinolaryngology at Medical University of Hannover. Participants were tested after initial CI fitting, six weeks after implantation, using the German version of the VTD (Vocal Tract Discomfort) Scale and VHI (9i) (Voice Handicap Index) as well as speech comprehension tests and a specifically developed questionnaire evaluating data concerning voice usage and other influential factors. Statistics included descriptive analysis, group comparisons (t-Test), Pearson correlation coefficient between VTD Scale and VHI, and hearing status. Patients with CI did show low scores in VTD Scale and VHI-9i (VTD mean=7.85 [SD=10.4]; VHI-9i mean=4.04 [SD=5.77]). We found neither a correlation between any of the speech comprehension tests and the VTD Scale nor the VHI-9i. Further, we could show no correlation between subjective Voice Handicap and/or Vocal Tract Discomfort and age or the kind of treatment. Patients included in this study did not show more subjective Voice Handicap or Vocal Tract Discomfort than normal hearing peers. Scores of VTD Scale and VHI-9i did not depend on the duration of hearing loss, speech comprehension, kind of treatment or age.

Using speech comprehension to qualify communication in classrooms: Influence of listening condition, task complexity and students’ age and linguistic abilities

Oral communication is a fundamental part of teaching and learning in classrooms. Correct reception of the teacher’s message is a necessary condition for good communication, though not sufficient to ensure that students will fully grasp its meaning. The traditional approach to the acoustic qualification of classrooms based on speech intelligibility alone might fail to capture the real impact of listening conditions on speech communication. A first aim of this study was to explore the use of a speech comprehension task combined with an assessment of listening effort as an alternative, more thorough way to qualify classroom acoustics. The speech comprehension task involved listening to sentences and was proposed to children aged 11–13 (N = 171). The test was administered collectively in the children’s classroom in three different listening conditions. A second aim of the study was to use the speech comprehension test to investigate the impact of task difficulty, listening condition, and individual characteristics on speech communication. For this scope the task difficulty was manipulated by varying the syntactic complexity of the sentences. Data were acquired on both percentages of correct answers and response times, the latter being indicative of listening effort. With reference to the aims of the study, the results indicate that: (i) testing speech comprehension enables a comprehensive and ecological qualification of the impact of classroom acoustics on real-world listening abilities; and (ii) the effect of listening conditions on sentence comprehension is mediated by sentence complexity, and by listeners’ age and linguistic abilities.

Effect of Parkinson Disease on Emotion Perception Using the Persian Affective Voices Test

Emotion perception plays a major role in proper communication with people in different social interactions. Nonverbal affect bursts can be used to evaluate vocal emotion perception. The present study was a preliminary step to establishing the psychometric properties of the Persian version of the Montreal Affective Voices (MAV) test, as well as to investigate the effect of Parkinson disease (PD) on vocal emotion perception. The short, emotional sound made by pronouncing the vowel "a" in Persian was recorded by 22 actors and actresses to develop the Persian version of the MAV, the Persian Affective Voices (PAV), for emotions of happiness, sadness, pleasure, pain, anger, disgust, fear, surprise, and neutrality. The results of the recordings of five of the actresses and five of the actors who obtained the highest score were used to generate the test. For convergent validity assessment, the correlation between the PAV and a speech prosody comprehension test was examined using a gender- and age-matched control group. To investigate the effect of the PD on emotion perception, the PAV test was performed on 28 patients with mild PD between ages 50 and 70 years. The PAV showed a high internal consistency (Cronbach's α = 0.80). A significant positive correlation was observed between the PAV and the speech prosody comprehension test. The test-retest reliability also showed the high repeatability of the PAV (intraclass correlation coefficient = 0.815, P ≤ 0.001). A significant difference was observed between the patients with PD and the controls in all subtests. The PAV test is a useful psychometric tool for examining vocal emotion perception that can be used in both behavioral and neuroimaging studies.

Speech audiometry and data logging in CIpatients : Implications for adequate test levels.

As part of postoperative cochlear implant (CI) diagnostics, speech comprehension tests are performed to monitor audiological outcome. In recent years, atrend toward improved suprathreshold speech intelligibility in quiet and an extension of intelligibility to softer sounds has been observed. Parallel to audiometric data, analysis of the patients' acoustic environment can take place by means of data logging in modern CI systems. Which speech test levels reflect the individual listening environment in arelevant manner and how can these be reflected in aclinical audiometric setting? In aretrospective analysis, data logs of 263adult CI patients were evaluated for sound level and the listening situation (quiet, speech in quiet, noise, speech in noise, music, and wind). Additionally, monosyllabic word comprehension in quiet was analyzed in experienced CI users at presentation levels of 40-80 dB. For the sound level in the acoustic environment of postlingually deafened adult CI users, data logging shows amaximum occurrence of speech signals in the range of 50-59 dB. This demonstrates the relevance of everyday speech comprehension at levels below 60 dB. Individual optimization of speech intelligibility with aCI speech processor should not be performed in the range of 65-70 dB only, but also at lower levels. Measurements at 50 dB currently seem to be auseful addition.

Speech Comprehension Difficulties in Chronic Tinnitus and Its Relation to Hyperacusis.

Objective: Many tinnitus patients complain about difficulties regarding speech comprehension. In spite of the high clinical relevance little is known about underlying mechanisms and predisposing factors. Here, we performed an exploratory investigation in a large sample of tinnitus patients to (1) estimate the prevalence of speech comprehension difficulties among tinnitus patients, to (2) compare subjective reports of speech comprehension difficulties with behavioral measurements in a standardized speech comprehension test and to (3) explore underlying mechanisms by analyzing the relationship between speech comprehension difficulties and peripheral hearing function (pure tone audiogram), as well as with co-morbid hyperacusis as a central auditory processing disorder.Subjects and Methods: Speech comprehension was assessed in 361 tinnitus patients presenting between 07/2012 and 08/2014 at the Interdisciplinary Tinnitus Clinic at the University of Regensburg. The assessment included standard audiological assessments (pure tone audiometry, tinnitus pitch, and loudness matching), the Goettingen sentence test (in quiet) for speech audiometric evaluation, two questions about hyperacusis, and two questions about speech comprehension in quiet and noisy environments (“How would you rate your ability to understand speech?”; “How would you rate your ability to follow a conversation when multiple people are speaking simultaneously?”).Results: Subjectively-reported speech comprehension deficits are frequent among tinnitus patients, especially in noisy environments (cocktail party situation). 74.2% of all investigated patients showed disturbed speech comprehension (indicated by values above 21.5 dB SPL in the Goettingen sentence test). Subjective speech comprehension complaints (both for general and in noisy environment) were correlated with hearing level and with audiologically-assessed speech comprehension ability. In contrast, co-morbid hyperacusis was only correlated with speech comprehension difficulties in noisy environments, but not with speech comprehension difficulties in general.Conclusion: Speech comprehension deficits are frequent among tinnitus patients. Whereas speech comprehension deficits in quiet environments are primarily due to peripheral hearing loss, speech comprehension deficits in noisy environments are related to both peripheral hearing loss and dysfunctional central auditory processing. Disturbed speech comprehension in noisy environments might be modulated by a central inhibitory deficit. In addition, attentional and cognitive aspects may play a role.

Cognitive assessment at bedside for iPad: A preliminary validation of a novel cognitive test for stroke patients.

Cognitive impairments are frequent in stroke. Cognitive testing is important for research, prognostication and planning in sub-acute stroke, but poses difficulties due to aphasia, hemineglect, hemiplegia and fatigue. We present the first steps towards a validation of a novel iPad-based test battery: Cognitive Assessment at Bedside for iPad (CABPad). Stroke patients and age matched healthy controls were tested with CABPad including tests for aphasia, neglect, episodic memory, attention span, executive function, working memory, mental speed, anosognosia, motor speed and depression. A re-test was performed after 1 month. Furthermore, a group of stroke patients was tested with CABPad and traditional neuropsychological tests. Fifty-four patients and 48 healthy controls were included in the first phase. Fifty-three patients (98%) were able to complete at least one test and 50 (92%) all tests at the first test point. Mean test duration in patients was 39 min (range 30-60). We found significant differences in test results at baseline between the two groups. Episodic memory mean difference: 8.5 (95% confidence interval: 4.3, 12.7). Symbol Digit Coding mean difference: 16.3 (95% confidence interval: 10.8, 21.7). The second phase included 16 patients. We found adequate to excellent correlation in the majority of the tests. The CABPad Speech Comprehension test and the Auditory Word Recognition subtest of the Western Aphasia Battery correlated with r = 0.82, p < 0.001. CABPad is useful for cognitive testing in stroke patients. It is easy to use for the examiner and patients alike. Immobile patients can be tested at bedside, irrespectively of upper extremity paresis, and the assessment can be performed in a relatively short timespan.

A Dynamic Speech Comprehension Test for Assessing Real-World Listening Ability.

Many listeners with hearing loss report particular difficulties with multitalker communication situations, but these difficulties are not well predicted using current clinical and laboratory assessment tools. The overall aim of this work is to create new speech tests that capture key aspects of multitalker communication situations and ultimately provide better predictions of real-world communication abilities and the effect of hearing aids. A test of ongoing speech comprehension introduced previously was extended to include naturalistic conversations between multiple talkers as targets, and a reverberant background environment containing competing conversations. In this article, we describe the development of this test and present a validation study. Thirty listeners with normal hearing participated in this study. Speech comprehension was measured for one-, two-, and three-talker passages at three different signal-to-noise ratios (SNRs), and working memory ability was measured using the reading span test. Analyses were conducted to examine passage equivalence, learning effects, and test-retest reliability, and to characterize the effects of number of talkers and SNR. Although we observed differences in difficulty across passages, it was possible to group the passages into four equivalent sets. Using this grouping, we achieved good test-retest reliability and observed no significant learning effects. Comprehension performance was sensitive to the SNR but did not decrease as the number of talkers increased. Individual performance showed associations with age and reading span score. This new dynamic speech comprehension test appears to be valid and suitable for experimental purposes. Further work will explore its utility as a tool for predicting real-world communication ability and hearing aid benefit.

Schooling Relates to Mental Health Problems in Adolescents with Cochlear Implants-Mediation by Hearing and Family Variables.

Aim of this multicenter study was to investigate whether schooling relates to mental health problems of adolescents with cochlear implants (CI) and how this relationship is mediated by hearing and family variables. One hundred and forty secondary school students with CI (mean age = 14.7 years, SD = 1.5), their hearing parents and teachers completed the Strengths and Difficulties Questionnaire (SDQ). Additional audiological tests (speech comprehension tests in quiet and noise) were performed. Students of special schools for hearing impaired persons (SSHIs) showed significantly more conduct problems (p < 0.05) and a significantly higher total difficulty score (TDS) (p < 0.05) compared to students of mainstream schools. Mental health problems did not differ between SSHI students with sign language education and SSHI students with oral education. Late implanted students and those with indication for additional handicaps were equally distributed among mainstream schools and SSHIs. However, students in SSHIs were more restricted to understand speech in noise, had a lower social background and were more likely to come from single-parent families. These factors were found to be partial mediators of the differences in mental health problems between the two school types. However, no variable could explain comprehensively, why students of SSHIs have more mental health problems than mainstream pupils.

Development and preliminary evaluation of a new test of ongoing speech comprehension

Objective: The overall goal of this work is to create new speech perception tests that more closely resemble real world communication and offer an alternative or complement to the commonly used sentence recall test. Design: We describe the development of a new ongoing speech comprehension test based on short everyday passages and on-the-go questions. We also describe the results of an experiment conducted to compare the psychometric properties of this test to those of a sentence test. Study sample: Both tests were completed by a group of listeners that included normal hearers as well as hearing-impaired listeners who participated with and without their hearing aids. Results: Overall, the psychometric properties of the two tests were similar, and thresholds were significantly correlated. However, there was some evidence of age/cognitive effects in the comprehension test that were not revealed by the sentence test. Conclusions: This new comprehension test promises to be useful for the larger goal of creating laboratory tests that combine realistic acoustic environments with realistic communication tasks. Further efforts will be required to assess whether the test can ultimately improve predictions of real-world outcomes.

Cognitive spare capacity: evaluation data and its association with comprehension of dynamic conversations.

It is well-established that communication involves the working memory system, which becomes increasingly engaged in understanding speech as the input signal degrades. The more resources allocated to recovering a degraded input signal, the fewer resources, referred to as cognitive spare capacity (CSC), remain for higher-level processing of speech. Using simulated natural listening environments, the aims of this paper were to (1) evaluate an English version of a recently introduced auditory test to measure CSC that targets the updating process of the executive function, (2) investigate if the test predicts speech comprehension better than the reading span test (RST) commonly used to measure working memory capacity, and (3) determine if the test is sensitive to increasing the number of attended locations during listening. In Experiment I, the CSC test was presented using a male and a female talker, in quiet and in spatially separated babble- and cafeteria-noises, in an audio-only and in an audio-visual mode. Data collected on 21 listeners with normal and impaired hearing confirmed that the English version of the CSC test is sensitive to population group, noise condition, and clarity of speech, but not presentation modality. In Experiment II, performance by 27 normal-hearing listeners on a novel speech comprehension test presented in noise was significantly associated with working memory capacity, but not with CSC. Moreover, this group showed no significant difference in CSC as the number of talker locations in the test increased. There was no consistent association between the CSC test and the RST. It is recommended that future studies investigate the psychometric properties of the CSC test, and examine its sensitivity to the complexity of the listening environment in participants with both normal and impaired hearing.

The differential effects of direct and indirect speech on discourse comprehension in Dutch and English listeners with and without aphasia

Background: In a previous study, we demonstrated that narratives containing direct speech constructions were easier to comprehend than narratives with indirect speech constructions for Dutch listeners with and without aphasia. There were two possible explanations for this finding: either that direct speech has increased liveliness compared to indirect speech or that direct speech is less grammatically complex.Aims: This study aimed to provide further insight into the mechanisms underlying the differences between direct and indirect speech constructions on discourse comprehension in Dutch. More specifically, it aimed to examine the role that the grammatical characteristics of direct and indirect speech play in discourse comprehension success by comparing English- and Dutch-speaking individuals with and without aphasia.Methods & Procedures: An English version of the Dutch iPad-based Direct Speech Comprehension (DISCO) test was developed. Twenty individuals with aphasia and 19 neurologically healthy control participants were presented with spoken narratives that contained either direct or indirect speech constructions. Their performance was compared to that of the participants of the Dutch DISCO study. To assess the effect of language on performance, we conducted a single analysis in which we contrasted the English data with the Dutch data.Outcomes & Results: Control participants performed better than participants with aphasia; English-speaking participants performed worse than Dutch participants, and narratives containing direct speech were easier to comprehend than narratives with indirect speech constructions. However, a subsequent analysis including only individuals with aphasia showed that the Dutch group differed from the English-speaking group: direct speech was only beneficial for the Dutch participants with aphasia.Conclusions: This study expanded on the findings of a previous study, in which a facilitating effect of direct over indirect speech constructions for audiovisual discourse comprehension was found. The differential effects of direct speech on comprehension in Dutch and English showed that rather than one or other explanation being “correct”, both liveliness and grammatical characteristics play a role in discourse comprehension success. Grammatically less complex constructions (direct speech) are not necessarily always easier to comprehend than grammatically more complex constructions (indirect speech) for individuals with aphasia. In our study grammatically simple constructions introduced grammatical ambiguity and therefore possible interpretation difficulties for the English-speaking participants with aphasia.

Effects of room acoustics on subjective workload assessment while performing dual tasks

This investigation examines the subjective workload assessments of individuals using the NASA Task Load Index (TLX), as they performed speech comprehension tests under assorted room acoustic conditions. This study was motivated due to the increasing diversity in US classrooms. Both native and non-native English listeners participated, using speech comprehension test materials produced by native English speakers in the first phase and by native Mandarin Chinese speakers in the second phase. The speech materials were disseminated in an immersive listening environment to each listener under 15 acoustic conditions, from combinations of background noise level (three levels from RC-30, 40, and 50) and reverberation time (five levels from 0.4 to 1.2 seconds). During each condition, participants completed assorted speech comprehension tasks while also tracing a moving dot for an adaptive rotor pursuit task. At the end of each acoustic condition, listeners were asked to assess the perceived workload by completing the six-item NASA TLX survey, e.g., mental demand, perceived performance, effort, and frustration. Results indicate that (1) listeners’ workload assessments degraded as the acoustic conditions became more adverse, and (2) the decrement in subjective assessment was greater for non-native listeners.

The effects of direct and indirect speech on discourse comprehension in Dutch listeners with and without aphasia

Background: Research on language comprehension in aphasia has primarily focused on comprehension of isolated words and sentences. Even though previous studies have provided insights into comprehension abilities of individuals with aphasia at the word and grammatical level, our understanding of the nature and extent of their language comprehension (dis)abilities is not yet complete. In contrast to the highly restricted semantic and syntactic interpretation of sentences, discourse comprehension requires additional pragmatic and non-linguistic skills.Aims: The purpose of this study was to assess language comprehension in individuals with and without aphasia at the discourse level. In particular, it addressed the question of whether the use of direct speech, compared to indirect speech, affects comprehension of narrative discourse in Dutch aphasic and non-brain-damaged (NBD) listeners.Methods & Procedures: The Direct Speech Comprehension (DISCO) test was developed to examine the effects of manipulating direct vs. indirect speech on discourse comprehension. Twenty-three individuals with aphasia and 20 NBD participants were presented with spoken narratives that contained either direct or indirect speech reports. The narratives were presented audio-visually on an iPad, and comprehension was assessed with yes/no questions.Outcomes & Results: The performance of the participants with aphasia was significantly poorer than that of the NBD participants. Moreover, a main effect for condition type was found, indicating that narratives with direct speech reports were better understood than narratives with indirect speech reports by listeners with and without aphasia. There was no interaction between group and condition type indicating that this main effect held for both the aphasic and the NBD listeners. However, for the participants with aphasia, there was an interaction between condition and Token Test error score indicating that the positive effect of direct speech constructions diminishes for individuals with poorer comprehension.Conclusions: Direct speech constructions facilitate language comprehension in listeners with and without aphasia. One explanation for this finding is the occurrence of additional “layers” of communication, such as intonation and facial expression, often accompanying direct speech constructions. An alternative account is the degree of grammatical complexity: In Dutch, the syntactic construction of indirect speech requires embedding, whereas in direct speech the introductory sentence and the quote are both main clauses. The finding that the beneficial effect of direct speech on language comprehension diminishes for individuals with severe aphasia may indicate that the DISCO is too difficult for them to reveal an effect of a subtle manipulation such as that of condition type.

Extending Communication for Patients with Disorders of Consciousness

The difficulty of distinguishing disorders of consciousness from certain disorders of communication leads to the possibility of false diagnosis. Our aim is to communicate with patients with disorders of consciousness through asking them to answer questions with "yes/no" by performing mental imagery tasks using functional magnetic resonance imaging (fMRI). A 1.5 T fMRI study with 5 patients and a control group is presented. Speech comprehension, mental imagery, and question-answer tests were performed. The imagery task of mental calculation produced equally distinct activation patterns when compared to navigation and motor imagery in controls. For controls, we could infer answers to questions based on imagery activations. Two patients produced activations in similar areas to controls for certain imagery tasks, however, no activations were observed for the question-answer task. The results from 2 patients provide independent support of similar work by others with 3 T fMRI, and demonstrate broader clinical utility for these tests at 1.5 T despite lower signal-to-noise ratio. Based on the control results, mental calculation adds a robust imagery task for use in future studies of this kind.

Anwendung des „Sprachverständnistests für komplexe syntaktische Strukturen (nach D.V. Bishop)“ bei 6- bis 8-jährigen Grundschülern

Standardized tests for speech comprehension have been lacking for the diagnostic investigation of primary school children with problems in hearing and speech development. The informal speech comprehension test for complex syntactic structures ("Sprachverständnistest für komplexe syntaktische Strukturen", SKSS), a shortened and in Swiss German translated modification of the Test for Reception of Grammar of Bishop, was analyzed for its logical validity of content, difficulty indices, selectivity, reliability and standard values in percent. We conducted the SKSS on 64 primary school children (first grade, average age 6.9 years) and 84 primary school children (second grade, average age 8.2 years). Four test sentences were excluded because of their ambiguous nature. The remaining 26 test sentences most often indicated low difficulty. However, there was an obvious difference between the two groups in terms of difficulty as well reliability. Based on our results, the test proved to be useful for screening. It allows both quantitative and qualitative interpretations.

A middle ear implant, the Symphonix Vibrant Soundbridge: retrospective study of the first 125 patients implanted in France.

The Vibrant Soundbridge is an active semi-implantable middle ear implant for the rehabilitation of patients with a sensorineural hearing loss who are not able to derive adequate benefit from conventional hearing aids. A retrospective study was performed to assess the overall level of satisfaction of implanted patients and to investigate the potential determinants of postoperative success. A retrospective survey of audiological data from repeated measures and subjective data from self-assessment scales administered postoperatively was conducted to determine the degree of benefit and satisfaction for Vibrant Soundbridge implantees. Twenty-one tertiary referral and teaching hospitals. The first 125 VSB implantees implanted in France between August 1997 and May 2001 were included in the study. No clinically significant change was observed for residual hearing postoperatively. Most patients (83%) reported they were either satisfied or very satisfied with the Vibrant Soundbridge. Analysis of correlation revealed a moderate correlation (Pearson coefficient r = 0.59) between the degree of benefit reported via the patient survey and the degree of benefit reported via the Glasgow Benefit Inventory. A moderate correlation (Pearson coefficient r = 0.66) was observed between speech comprehension scores in quiet for the preoperative unaided condition and the postoperative aided Vibrant Soundbridge condition. No correlation was observed between subjective reports of satisfaction postoperatively and performance on preoperative objective tests or patient characteristics. The results indicate a high level of satisfaction with the VSB as a treatment of sensorineural hearing impairment in patients with a wide range of characteristics. Preoperative scores for unaided speech comprehension tests in quiet may be a potential indicator of success on aided Vibrant Soundbridge speech comprehension tests postoperatively but do not reflect patient satisfaction with the device reported on self-assessment scales.

The role of the promontory stimulation test in cochlear implantation

To date, 290 adults have been implanted in the cochlear implant programme in Sydney (Australia), where the promontory stimulation test (PST) is routinely used to assess implant candidacy. There has been much controversy over the exact role and value of this test. Pre- and postoperative speech comprehension tests of 150 implantees were analysed, and scores were compared with preoperative PST performances. Eighty-nine per cent of the patients perceived sound when the promontory was stimulated electrically. This group of implantees scored 81% on CID speech tests at 12 months postoperatively, compared to the minority who lacked preoperative promontory stimulability, who scored 42%. The PST is therefore predictive of greater speech benefits after implantation. It also provides an important psychophysical experience of hearing electrical sound.

Speech-specific cortical potentials--methodologic aspects and initial clinical results

The purpose of this study was to find out whether specific cortical potentials can be evoked and identified after word stimulation. The clinical relevance was to be investigated in patients with aphasic syndromes. In 20 young adults with no signs of hearing impairment and in patients with manifest aphasic syndromes, word-evoked cortical potentials were compared with those after an equivalent noise stimulus. The test words were selected from the Freiburger Speech Comprehension Test. The duration of the words was between 450 and 640 ms. The stimulus was presented monaurally. The peak level was 70 dB HL. The noise stimulus was produced by modifying a low-band noise. Potentials were measured between the ipsilateral mastoid and the contralateral forehead. Data were analysed offline. In healthy persons, the potentials after word and noise stimulation did not differ until 100 ms after the stimulus onset. After noise stimulation a negative maximum could be seen 100 ms after the stimulus onset, and a positive maximum 200 ms after the stimulus onset. After word stimulation, a positive maximum of higher amplitude than after noise stimulation was measured 150 ms after the stimulus onset, and a negative maximum was measured 270 ms after the stimulus onset. In all test persons the difference curve of word-and noise-evoked potentials revealed a speech-specific component 170 ms (N 170) after the stimulus onset. The single-word analysis showed that the potentials depend on the phonemes of the test word. The potentials do not alter when the stimulus side is changed. In patients with aphasia the potentials depend on the grade of the disturbance of speech perception: global and Wernicke's aphasia show no significant difference of speech-and noise-evoked potentials, whereas in Broca's aphasia a speech specific maximum is apparent. The speech-specific component may be regarded as a paradigm of cortical speech detection processes. Electrophysiological speech audiometry by means of word-evoked cortical potentials seems possible and may be used for clinical purposes.