Single-sided deafness affects language and auditory development - a case-control study.

OBJECTIVES: To examine auditory, linguistic and cognitive outcomes of children with single-sided deafness (SSD). An increasing body of research suggests that children with SSD lag behind with respect to their normal hearing (NH) peers. In this study, we tap into certain developmental skills. DESIGN: Case-control study. PARTICIPANTS: Twenty-one children with SSD between 5 and 15 years of age participated. Per child with SSD, two NH control children were matched on age and gender. OUTCOME MEASURES: Morphology, syntax and vocabulary were examined, and performance was assessed in depth by focusing on subskills and type of errors made. Furthermore, tests of short-term and working memory were conducted, and aspects of hearing disability were assessed by means of the speech spatial and qualities of hearing questionnaire (SSQ). MAIN RESULTS: The children with SSD lagged behind in their scores on the three language tests and showed some differences to the NH group concerning type of errors and difficulty of the several subskills. Furthermore, scores on the SSQ indicated that in daily life, the children with SSD experience problems in spatial hearing and in understanding speech in noisy situations and that the effort they have to put into listening and in understanding speech is considerably greater than in NH children. CONCLUSIONS: This study showed differences between children with SSD and NH children on several language skills and on auditory behaviour. Possibly, early intervention could prevent such language difficulties and minimise problems with spatial hearing and speech understanding.

The importance of early home-based guidance (EHBG) for hearing-impaired children and their families in Flanders.

This state-of-the-art report describes the rationale and evidence for family-centred early intervention after newborn hearing screening (NHS). More specifically, we document the organisation and practice of early home-based guidance (EHBG) in Flanders, as well as the new challenges and paradigm shifts induced by NHS. Since the introduction of NHS, the number of participants with bilateral hearing loss entering one of the five EHBG centres in Flanders (one in each of the region's provinces) before the age of twelve months has doubled. About half of the screened population receive EHBG and about 80% of them do so before the age of six months. However, there is enormous variation between the different provinces and this has still to be clarified.

Newborn hearing screening and cochlear implantation: impact on spoken language development.

OBJECTIVES: This study retrospectively evaluates the effect of newborn hearing screening on age at diagnosis, age at cochlear implantation and spoken language development in severely hearing-impaired children. METHODS: Age at diagnosis, age at cochlear implantation and language development were evaluated in a group of early screened (n = 149) and a group of late screened (n = 139) severely hearing-impaired children. Language outcomes were quantified as language quotients (LQs) on the Reynell Developmental Language Scales and Schlichting Expressive Language Test at 1,2, and 3 years after cochlear implantation. RESULTS: Early screened children were significantly younger than late screened children at the time of hearing loss diagnosis and cochlear implantation. Furthermore, early screening was associated with better receptive and expressive spoken language skills after cochlear implantation. CONCLUSION: The results of this retrospective study indicate that the newborn hearing screening program in Flanders and The Netherlands resulted in earlier intervention in deaf children, which beneficially influenced spoken language development.

A one year prospective study of neurogenic stuttering following stroke: incidence and co-occurring disorders.

UNLABELLED: In this prospective study, data on incidence, stuttering characteristics, co-occurring speech disorders, and recovery of neurogenic stuttering in a large sample of stroke participants were assessed. Following stroke onset, 17 of 319 participants (5.3%; 95% CI, 3.2-8.3) met the criteria for neurogenic stuttering. Stuttering persisted in at least 2.5% (95% CI, 1.1-4.7) for more than six months following the stroke. Participants with comorbid aphasia presented with a significantly higher frequency of stuttering compared to the group without aphasia (U=13.00, p((1-tailed))=.02) but no difference was found for participants with co-occurring dysarthria and/or cognitive problems. Participants with neurogenic stuttering did not differ from those without stuttering in terms of stroke risk factors or stroke etiologic subtypes. Although the incidence of stuttering following stroke is lower than that for aphasia or dysarthria, these results show that clinicians should take neurogenic stuttering into account when assessing stroke participants' speech and language. LEARNING OUTCOMES: : Readers will be able to: (1) understand the need for systematic, prospective studies in neurogenic stuttering; (2) know the incidence and prevalence of neurogenic stuttering following stroke; and (3) know how neurogenic stuttering co-occurs with other speech-language disorders following stroke.

Functional benefit of the bone-anchored hearing aid with different auditory profiles: objective and subjective measures.

OBJECTIVES: To examine sentence recognition and self-report outcomes in hearing-impaired persons with different auditory profiles and who were fitted unilaterally with a bone-anchored hearing aid. STUDY-DESIGN: Prospective cohort study. SETTING: Tertiary referral unit. PATIENTS: Data were collected of six patients with single-sided deafness (SSD), seven with a mild to severe hearing loss at the bone-anchored hearing aid side and (near-)normal hearing at the other side and six with a severe bilateral hearing loss. MAIN OUTCOME MEASUREMENTS: Sound field thresholds, and sentence recognition in noise (presented from different angles) with bone-anchored hearing aid, without bone-anchored hearing aid and with bone-anchored hearing aid and other ear occluded. In addition, the Speech, Spatial and Qualities of hearing scale and the Abbreviated Profile of Hearing Aid Benefit questionnaire were administered as self-report measures. RESULTS: Patients with single-sided deafness listened mainly with their non-bone-anchored hearing aid ear, although the bone-anchored hearing aid lifted the head shadow effect. Patients with mild to severe hearing loss at the bone-anchored hearing aid side and (near-)normal hearing at the other side performed significantly differently in aided and unaided conditions and even regained limited binaural sensitivity with the device. The latter was also true for the patients with severe bilateral hearing loss. However, their hearing loss at the non-bone-anchored hearing aid side was too great to contribute to hearing and they listened predominantly with their bone-anchored hearing aid. Self-report outcomes provided useful information on hearing disability, although this information was not significantly differently for the 3 groups of patients. CONCLUSIONS: The bone-anchored hearing aid enhanced performance in different hearing configurations, albeit to different extents.

Prevalence of tinnitus and audiometric shape.

OBJECTIVES: Studies of tinnitus are often conducted on patient populations presenting for treatment. It is, however, difficult to generalise prevalence numbers and aetiological results from these studies to a healthy, elderly population. The first aim of our study was to determine the prevalence of tinnitus in an otologically screened population between 55 and 65 years old. Secondly, both prevalence and the specific characteristics of tinnitus were compared in subjects with either a flat audiogram, a high-frequency gently sloping audiogram or a high-frequency steeply sloping audiogram. METHODS: 1147 subjects (549 males and 598 females) were recruited through population registers and underwent thorough clinical and audiological examinations. Subjects who reported tinnitus in the general questionnaire about medical history and environmental exposure were invited to complete an additional questionnaire on tinnitus history. RESULTS: The prevalence of tinnitus was 19.3% according to the general questionnaire on medical health and environmental exposure and 11.8% according to the additional detailed tinnitus-specific questionnaire. Furthermore, our results indicate that gender has a significant effect (tinnitus is more common in males than in females), as does audiometric configuration (tinnitus is more common in subjects with a high-frequency steeply sloping audiogram than in subjects with a flat audiogram). Both effects were significant in noise-/solvent-exposed subjects, as well as in non-exposed subjects. Finally, comparison of "tinnitus characteristics" in subjects categorised by audiogram configuration revealed significant differences in loudness, pitch, temporal variability and family history of tinnitus.

Digital hearing aids and future directions for hearing aids.

In recent years many technical evolutions have been applied in hearing aids. In this paper differences between analog, programmable and fully digital hearing aids, the basic and supplementary functions of a hearing aid, and some important issues and future directions for digital hearing aids will be mentioned.

Psychophysical evidence for a general temporal processing deficit in children with dyslexia.

The hypothesis of a general (i.e. cross-modal) temporal processing deficit in dyslexia was tested by examining rapid processing in both the auditory and the visual system in the same children with dyslexia. Participants were 10- to 12-year-old dyslexic readers and age-matched normal reading controls. Psychophysical thresholds were estimated for auditory gap and visual double flash detection, using a two-interval, two-alternative forced-choice paradigm. Significant group differences were found for the auditory and the visual test. Furthermore, temporal processing measures were significantly related to word and pseudo-word reading skills. As 70% of the dyslexic readers had significantly higher thresholds than controls for both auditory and visual temporal processing, the evidence tends to support the hypothesis of a general temporal processing deficit in children with dyslexia.

Comparison of procedures to determine electrical stimulation thresholds in cochlear implant users.

OBJECTIVE: This study was designed to evaluate threshold estimation procedures for cochlear implantees, both for clinical and research purposes. Precision and testing time of eight procedures were evaluated. These procedures included three variations of two adaptive tasks and two variations of an adjustment procedure. DESIGN: Electrical thresholds were obtained with eight different procedures. For each procedure, one of three tasks was combined with one of four decision strategies. With the adjustment task, current level was adjusted from "inaudible" to "just audible" or from "clearly audible" to "just audible." With the two adaptive tasks (i.e., "count the number of pulses" and "choose the interval with the pulse"), current level was adjusted during the sequence of trials by subjects' preceding responses according to three decision criteria (Levitt, 1971). Experimental data were collected on both an apical and a basal channel of six Laura cochlear implantees, and test-retest measures were obtained for each procedure, channel and subject. Moreover, total testing time was recorded in each test, to examine the trade-off with precision, and to investigate the feasibility of the procedures in a clinical setting. RESULTS: In general, the "count the pulses" procedures yield higher threshold values than the "choose the interval with the pulse" and adjustment procedures. Precision was not a statistically significant factor, although the test-retest variation was approximately a factor of 2 larger in the adjustment procedures than in the adaptive procedures. Test duration differences were large. Moreover, analyses of the adaptive procedures showed that a stable estimate requires at least six reversals and that the first four reversals should not be taken into account for threshold estimation. CONCLUSIONS: In a clinical setting, where precision and time are important parameters, precise thresholds can be obtained with the adjustment procedure. However, for research purposes, it is advised to use the "choose the interval with the pulse" task together with one of the transformed up-down decision criteria.

Gap detection in single- and multiple-channel stimuli by LAURA cochlear implantees.

Gap-detection thresholds were determined for different complex patterns of electrical stimulation in four postlingually deafened LAURA cochlear implantees, to examine the nature of within- and across-channel auditory processes in more detail. Gap detectability was examined as a function of stimulus complexity (one, two, or three channels), channel distance within and across multichannel pre- and post-gap markers, stimulus asymmetry, and pulse rate. All markers roved in duration from 200 to 500 ms to ensure that subjects were not using overall stimulus duration as a cue. Gap-detection thresholds for all subjects were short (< 5 ms) when the pre- and post-gap markers stimulated the same single or multiple channels, even when the distance between simultaneously stimulated channels was large (exp. 1). For some subjects, gap detectability was more difficult in the across-channel condition, when the pre- and post-gap markers each stimulated different channels, although performance improved substantially in most subjects after extensive training (exp. 2). Additional tests with random maskers also suggest that neural interaction only affects performance mildly, and that the magnitude of the gap-detection threshold probably depends more on the subject's cognitive (in)ability to attend to the temporal gap than on the temporal acuity of their auditory system. Other stimulus conditions showed a difference in performance related to the order of the markers: gap thresholds were longer when the pre-gap marker stimulated one channel and the post-gap marker stimulated two or more channels, than vice versa (exp. 3). In addition, gap thresholds of three of the subjects increased with decreasing pulse rate from 1250 to 400 pps, a finding which may be related to the rate of the speech processing strategies used by each individual implantee (exp. 4).

Natural vowel and consonant recognition by Laura cochlear implantees.

OBJECTIVE: This study was performed to examine whether spectral and temporal properties of speech sounds are transferred effectively by the Laura cochlear implant device, and to determine whether listeners with different levels of performance use the same type of information to understand speech. DESIGN: Twenty-five adult Laura cochlear implantees identified 12 repetitions of 10 vowels in /hVt/ utterances and 16 consonants placed in intervocalic /a/ context. The stimulus-response confusion matrices were analyzed in terms of relative information transmission scores (Miller & Nicely, 1955), and they were subjected to multidimensional INDSCAL analyses to examine whether a similar pattern of results would emerge when no prior assumptions were made about the division of categories. RESULTS: To examine perception for different levels of performance, the vowel and consonant confusion data were divided into three groups of subjects: the better, intermediate, and poorer performers. In general, the INDSCAL analyses confirmed the results obtained from the information transmission analyses. However, they also supplemented it with other perceptually relevant cues for cochlear implantees, as well as with the weightings over different perceptual dimensions for different types of performers. These analyses suggest that although all subjects use the same type of information, the better performers are more capable of using these different cues than poor performers.

Speech intelligibility in noisy environments with one- and two-microphone hearing aids.

In this study speech intelligibility in background noise was evaluated with 10 binaural hearing-aid users for hearing aids with one omnidirectional microphone and a hearing aid with a two-microphone configuration (enabling an omnidirectional as well as a directional mode). Signal-to-noise ratio (SNR) measurements were carried out for three different types of background noise (speech-weighted noise, traffic noise and restaurant noise) and two kinds of speech material (bisyllabic word lists and sentences). The average SNR improvement of the directional microphone configuration relative to the omnidirectional one was 3.4 dB for noise presented from 90 degrees azimuth. This improvement was independent of the specific type of noise and speech material, indicating that one speech-in-noise condition may yield enough relevant information in the evaluation of directional microphones and speech understanding in noise.

Developments in speech processing for cochlear implants.

The status of speech processing for cochlear implants is reviewed. Points of interest to enhance further speech intelligibility based on improved signal processing, are discussed.

Reoperation for a symptomatic double gallbladder.

A case of a complicated postoperative course after laparoscopic cholecystectomy in which, ultimately, gallbladder duplication was suspected and confirmed at laparotomy is described. The diagnostic tools, differential diagnosis, and therapy are discussed. After open cholecystectomy patients' complaints dissolved. Awareness of the possibility of a double gallbladder in case of persisting symptoms after laparoscopic cholecystectomy can lead to diagnosis of this condition at an earlier stage.

Frequency and duration discrimination of short first-formant speechlike transitions.

Frequency and duration discrimination thresholds of short rising and falling one-formant speechlike transitions without a steady state were determined by means of same/different paired comparison tasks in two experiments. When frequency extent is varied (experiment 1), just noticeable differences decrease with increasing transition duration. Expressed in Hz, thresholds are, on average, 70, 63, and 58 Hz for 20, 30, and 50 ms, respectively. However, when transition duration is varied at a constant frequency extent (experiment 2), difference limens increase with increasing duration and are, on average, 2.7, 4.5, and 4.9 ms for standard transitions of 20, 30, and 50 ms, respectively. The thresholds determined in the two experiments indicate that different psychoacoustical cues are used depending on whether final frequency (experiment 1) or transition duration (experiment 2) are varied. Both experiments were performed at two different frequency regions (between 200 and 700 Hz and between 500 and 1000 Hz), but the results did not differ per region. In addition, no significant differences were found between rising and falling transitions. Particular attention was paid to a methodological issue, viz., the extent to which sensitivity changes as a result of different proportions of catch trials. It was found that the listeners maintained the same response strategies throughout the tests, as their performance is similar, irrespective of the number of catch trials included in the testing sessions.

Pilot study to determine the interaction of oxiracetam with antiepileptic drugs.

Oxiracetam, a nootropic drug, could be of potential use in the treatment of memory disturbances in patients with epilepsy who are using antiepileptic drugs. The half-life of oxiracetam appears to be influenced by the concomitant use of carbamazepine or valproic acid, necessitating more frequent administration of oxiracetam than is recommended for other conditions. No effect was observed on the serum concentrations of these antiepileptic drugs by oxiracetam. Long term concurrent use of oxiracetam and antiepileptic agents does not appear to be contraindicated.

Double-blind placebo-controlled, neuropsychological and neurophysiological investigations with oxiracetam (CGP 21690E) in memory-impaired patients with epilepsy.

A double-blind placebo-controlled between-patient study was carried out to assess the effects of oxiracetam (CGP 21690E) on memory function in patients with epilepsy. During a 12-week period, either oxiracetam (800 mg t.i.d.) or placebo was given to 30 patients. Twenty-four of the patients had a partial epilepsy. Most patients were on monotherapy carbamazepine. Effect of oxiracetam on memory and related cognitive functions were assessed, using a computerized neuropsychological testing method, while concomitant electrophysiological changes were investigated with routine EEG registration, power spectrum analysis and auditory evoked event-related potentials (P300). Subjective evaluation of well-being was quantified with a mood rating scale. The results did not show any meaningful changes in memory function. This finding is in line with the subjective patient reports and the P300 measures.

Double-blind crossover trial of lamotrigine (Lamictal) as add-on therapy in intractable epilepsy.

A double-blind, placebo-controlled trial is reported of lamotrigine as add-on treatment in therapy-resistant epilepsy. A within-patients serial design was used, with two 3-month treatment periods and an intervening 6-week washout/crossover period. An unblinded investigator adjusted lamotrigine dosage to achieve a plasma concentration within a previously predicted therapeutic range. All patients had therapy-resistant partial seizures, some in combination with other seizure types and were without serious neurological or intellectual deficit. Of 34 patients recruited only one was withdrawn because of an adverse experience (maculo-papular rash) probably related to the experimental drug and 30 completed the trial. The other 3 withdrawals were due to default during baseline, dispensing error and cholecystectomy. There was a modest statistically significant reduction in total and partial seizures on lamotrigine compared to placebo treatment. There was no difference in adverse experiences or abnormal biochemical or haematological findings between the lamotrigine and placebo periods. The plasma concentrations of concomitantly administered antiepileptic drugs were not affected by lamotrigine treatment. It is concluded that lamotrigine shows promise as an antiepileptic drug with low toxicity.

Comparison of the effects of lamotrigine and phenytoin on the EEG power spectrum and cortical and brainstem-evoked responses of normal human volunteers.

Phenytoin and lamotrigine (a new antiepileptic drug with an animal experimental profile resembling phenytoin) have closely similar effects on the quantitative pharmaco-electroencephalogram. These characteristics do not provide a basis for the functional classification of antiepileptic drugs nor for prediction of clinical efficacy, but they do give some insight into the probable secondary psychotropic effects which may arise with use of these drugs. Central conduction in cortical (visual) and brainstem (auditory) event-related potentials are not influenced by either drug, but peripheral nerve conduction is delayed with the use of phenytoin as reflected in increased latency wave I in the brainstem auditory-evoked response. The evidence suggests that in equivalent therapeutic dosage, lamotrigine may be less neurotoxic than phenytoin.

Electroencephalographic findings in antiepileptic drug trials: a review and report of 6 studies.

A recent survey has shown that the EEG is of doubtful value as an outcome variable in clinical antiepileptic drug (AED) trials. Analysis of findings in 6 trials shows that in only two no consistent effect was seen; that in two power spectral analysis provided additional information to confirm changes in background activity; that in one a close relationship could be established between reduction in frequency of epileptiform discharges and administration of the trial drug (lamotrigine), and that in one, even though no correlation was apparent during use of the AED, there was an increase in frequency of both discharges and seizures on withdrawal (CGP 11952). In general the EEG would appear to be unsuitable as an outcome variable for assessing drug efficacy in AED trials. On the other hand it may give insight into the mode of drug action. Conceivably more efficient use could be made of the EEG if the methodology--including patient selection, consideration of circadian rhythms and of combination AED therapy, and standardized long-term recording--were to be improved and automation and quantification techniques used.