TTC7A mutation must be considered in patients with repeated intestinal atresia associated with early inflammatory bowel disease: Two new case reports and a literature review.

TTC7A mutations cause multiple neonatal intestinal atresias with early inflammatory bowel disease and severe combined immunodeficiency. There are no treatment protocols for this rare disease. Two new cases are described for which radical early treatment measures - total enterectomy, home parenteral nutrition, immunoglobulin therapy and intravenous antibiotic prophylaxis - have allowed both patients to develop optimally.

Development of auditory asymmetry in transient evoked otoacoustic emissions in pre-term infants.

We previously reported that transient evoked otoacoustic emissions (TEOAEs) continue to develop after the onset of cochlear function in pre-term infants from 34 to 39 weeks of conceptional age (Morlet et al., 1996). The time-course of development differed between genders. Reported here are findings of further analysis of data from the study cohort, comprising 1020 ears of 510 pre-term neonates (conceptional age ranging from 34 to 39 weeks), demonstrating developmental differences between right and left ears. The left ear of female pre-term infants showed enhancement of TEOAE amplitude at low and medium frequencies with age, whereas differences were less dramatic in the right ear. In male infants, TEOAE amplitude decreased in several frequency bands at high frequencies, above 4 kHz, between 34 and 39 weeks conceptional age; most developmental differences were found to be more dramatic in the right than in the left ear. It is tempting to speculate that these developmental features underlie well-known inter-aural asymmetries that have been demonstrated in the adult human.

[Systematic screening of deafness at a maternity ward using evoked otoacoustic emissions: practical aspects and parental attitudes]. / Dépistage systématique de la surdité en maternité par otoémissions acoustiques provoquées: aspects pratiques et attitudes parentales.

OBJECTIVE: Evaluation of the feasibility and parental attitudes towards a hearing screening programme using evoked otoacoustic emissions, implemented in a maternity ward in France. METHODS: A hearing screening test using transiently evoked otoacoustic emissions (TEOAE) was proposed to each baby, and an anonymous questionnaire was given to parents to assess their attitudes towards the screening procedure. RESULTS: Although the refusal of the test reached 16% (mainly during the first two weeks of the program), more than 92% of parents judged the test as being useful, and 65% wished it to be systematically done. However, nearly 35% of parents admitted to have a low level anxiety about being unnecessarily worried by the test results. One hundred and twenty-four babies were screened. Fifty three per cent of the tests have been performed in less than ten minutes, with an average of 12.2 minutes. This duration does not include delays due to programme and babies management. False positive rate (uni or bilateral fail) was 10.5% at the first stage. Repeating the test before discharge decreased the false positive rate to 6.5%. CONCLUSION: Although limited in time, this study shows that a systematic hearing screening programme using TEOAE is possible and should be done in France. False positive rate was below 7%, and the test was considered as useful by more than 90% of parents, although knowledge about deafness in childhood and its consequences were clearly insufficient.

EEG bispectral index and hypnotic component of anaesthesia induced by sevoflurane: comparison between children and adults.

This prospective study was designed to evaluate the correlation between the electroencephalographic bispectral index (BIS) and the hypnotic component of anaesthesia (CA) induced by sevoflurane in 27 children and 27 adult patients. BIS and CA were compared at loss of consciousness (LOC) and on recovery of consciousness (ROC). Mean (SD) BIS decreased significantly at LOC in children and adults from 94 (2.7) to 87.4 (4) and from 96.2 (2) to 86.7 (4.4), respectively, without any difference between groups. Correlation coefficients (p) between BIS and CA at LOC were -0.761 in children and -0.911 in adults. BIS increased significantly at ROC in children and adults from 74.1 (4.2) to 86.7 (2) and from 80.2 (5) to 90.7 (3), respectively, without any difference between groups. Correlation coefficients between BIS and CA in ROC were -0.876 in children and -0.837 in adults. BIS values at ROC were not different from those at LOC in either group. These data demonstrate that BIS correlates with the hypnotic component of anaesthesia induced by sevoflurane in children as well as in adults.

[Hearing disorders screening in neonates at risk]. / Dépistage des troubles auditifs chez des nouveau-nés à risque.

The present report concerns a three year, eight month hearing screening in 1 531 high-risk neonates by means of two successive transient evoked otoacoustic emissions (TEOAE) recordings followed, cin cases of suspected hearing loss, by brainstem auditory evoked potential (BAEP) recording and otolaryngology (ORL) consultation. After TEOAE1 and 2 and BAEP testing, 1 361 infants (88.9%) were declared normal, and 170 (11%) suspected of hearing loss. Of these 170, 58 showed bilateral and 26 unilateral impairment. Definite hearing loss on ORL consultation was diagnosed in 14 infants (0.9% of the screened population as a whole); 22 are still followed, while 86 (5.6%) failed to consult for diagnosis. The mean age on diagnosis of definite hearing loss on ORL consultation was 9.9 +/- 4.9 (range 4-20) months. Several auditory function risk factors have been proved to be more frequent in deaf than in normal children. Our results show that early hearing loss screening in at-risk neonates needs to be pursued.

Effect of sleep stages on synchronized spontaneous otoacoustic emissions in pre-term neonates.

OBJECTIVES: In infants, auditory tests are mainly performed during sleep, since they spend most of their time asleep, and because quiet is required for the duration of the recording session to obtain a precise and reliable response. The aim of this study was to investigate the effect of sleep stages on synchronized spontaneous otoacoustic emissions (sSOAEs) in pre-term neonates at the age where the sleep states begin to be well established and auditory screening can be performed in a neonatology unit before discharge. METHODS: Synchronized SOAEs were repeatedly recorded during a polygraphic sleep recording using the Otodynamic ILO88 system in 10 pre-term neonates at 36 weeks post-conception. RESULTS: Variations of sSOAE peak numbers occurred in each subject during the recording session. There was no clear relation between sSOAE peak number fluctuations and the different sleep stages. CONCLUSIONS: The sSOAE variations appeared to be closely related to experimental conditions, i.e. the mean background noise level. sSOAEs with the highest amplitude were always recorded; however, those with the smallest amplitude were the first to disappear from the recordings with higher background noise.

Acuteness of preoperative factors to predict hearing preservation in acoustic neuroma surgery.

OBJECTIVES: To determine in patients with acoustic neuromas the predictive factors of hearing preservation according to clinical, radiological, and electrophysiological parameters and to evaluate, for each of these predictive factors, the percentage of patients with preserved hearing. STUDY DESIGN: The study involved 107 candidates for hearing preservation attempt. Mean age was 49.7 +/- 11.4 years. Quantitative and qualitative parameters were prospectively studied. Quantitative parameters were age, duration of functional complaints, hearing loss assessed by pure tone and speech audiometry, and auditory brainstem responses (ABRs). Qualitative parameters (expressed in percentage of presence) were sex, functional complaints, vestibular deficit revealed by vestibular testings, well-shaped ABRs, wave I, III, or V of ABRs, and transient evoked otoacoustic emissions (TEOAEs). METHODS: Patients were divided into two groups according to whether their hearing was preserved (52.3%) or not preserved (47.7%). First, quantitative and qualitative factors were compared between both groups to identify predictive factors. Second, all patients were considered together and the percentage of hearing preservation was determined according to the presence of each predictive factor. RESULTS: The results confirmed the predictive value of classic parameters such as preoperative hearing level, radiological data, and trace of ABRs. They also emphasized the predictive role of other parameters such as short duration of hearing loss, presence of wave III in ABRs, and presence of TEOAEs. CONCLUSIONS: The size of the tumor and the preoperative hearing levels are longstanding predictive factors of hearing preservation in acoustic neuroma surgery, and candidates for hearing preservation are therefore now selected according to these factors. This study added more recent predictive factors and, among the 10 factors identified as predictive, the most relevant to hearing preservation were the presence of TEOAEs (69.7%), short duration of hearing loss (66.7%), and presence of wave III in ABRs (66.7%).

Development of human cochlear active mechanism asymmetry: involvement of the medial olivocochlear system?

To study the functional development of the medial olivocochlear system, transient-evoked otoacoustic emission suppression experiments were conducted in 73 ears of 38 pre-term and 11 full-term neonates. The continuous contralateral stimulation was a broad band white noise, presented at 70 dB SPL. Efferent suppression was determined by subtracting the without-contralateral stimulation condition from the with-contralateral stimulation condition. Across this population, a mean suppression effect of contralateral stimulation on transient-evoked otoacoustic emissions was found, with most of the suppression effect observed after 8 ms. The amount of suppression is linearly, positively correlated with the conceptional age. In the subgroup of bilaterally tested neonates, the suppression of transient-evoked otoacoustic emissions is similar in the right ear and the left ear in subjects whose conceptional age is less than 36 weeks and significantly higher in the right ear than in the left ear in older neonates. This last observation was seen at frequencies where transient-evoked otoacoustic emission amplitudes became higher in the right ear than in the left ear as the conceptional age increased, a finding already reported in adults. This study shows that the functional adult pattern of the medial efferent system, probably involved in the detection of signals in noise such as speech sounds, seems to appear gradually in neonates and represents one of the several arguments in favor of functional auditory lateralization in humans, with a right ear advantage.

Vestibular evoked myogenic potentials in humans: a review.

The human vestibule has preserved an ancestral sound sensitivity and it has been suggested that a reflex could originate from this property, thus inducing cervical muscle microcontractions secondary to strong acoustic stimulations. This reflex is assumed to originate in the saccule, the afferent pathways being either the vestibulocochlear nerve or the inferior vestibular nerve, and the efferent pathways the vestibulospinal tract. Averaging these muscular responses allows vestibular evoked myogenic potentials (VEMPs) to be obtained. The responses consist of two alternatively positive and negative successive waves (p13-n23, p33-n43). The characteristics of this reflex are defined in the literature as follows: it has been established that VEMP amplitude depends on muscular tension. All studies give concording evidence that in healthy subjects the first component of VEMP is more consistent than the second. Binaural stimulation is always responsible for responses of greater amplitude than those obtained from monaural stimulation. Following monaural stimulation, however, VEMPs are either of greater amplitude on the muscle ipsilateral to the stimulation or of the same amplitude on both muscles. There is consensus in the literature demonstrating that VEMP amplitude depends on stimulus intensity: the threshold of VEMP occurrence is clearly above auditory level but varies from one individual to the next. In the 1970s, recordings performed in cases of specific audiovestibular defects suggested that the reflex receptor could be the saccule. More recent studies suggest that the cochlea too could be involved in the response. Likewise, while a number of studies tend to demonstrate that VEMPs depend on vestibular integrity, others suggest that afferent pathways could be of both cohlear and vestibular origin. Finally, while it has been suggested that VEMP efferent pathways travel through the vestibulospinal tract, whether it is the lateral or the medial vestibulospinal tract that is concerned remains to be clarified. A few points regarding VEMP receptors and afferent and efferent pathways call for further investigation. They are inaccurate for use in routine vestibular examination. Once precise receptor localization and pathways are clarified, VEMP recording will provide both a straightforward non-invasive exploration of each vestibule independently and an attractive method by which to explore otolithic receptors and vestibulospinal pathways.

Auditory screening in high-risk pre-term and full-term neonates using transient evoked otoacoustic emissions and brainstem auditory evoked potentials.

The present report concerns a 3 year, 8 month hearing screening in 1531 high-risk neonates by means of two successive transient evoked otoacoustic emission (TEOAE) recordings followed, in cases of suspected hearing loss, by brainstem auditory evoked potential (BAEP) recording and otolaryngology (ORL) consultation. After TEOAE 1 and 2 and BAEP testing, 1361 infants (88.9%) were declared normal, and 170 (11.1%) suspected of hearing loss. Of these 170, 58 showed bilateral and 26 unilateral impairment. Definite hearing loss on ORL consultation was diagnosed in 14 infants (0.9% of the screened population as a whole); 22 are still being followed, while 86 (5.6%) failed to consult for diagnosis. The mean age on diagnosis of definite hearing loss was 9.9 +/- 4.9 (range 4-20) months. Several auditory function risk factors proved more frequent in deaf than in normal children. Our results show that early hearing loss screening in at-risk neonates needs to be pursued.

Autoregulation of human inner ear blood flow during middle ear surgery with propofol or isoflurane anesthesia during controlled hypotension.

UNLABELLED: We used controlled hypotension to obtain a bloodless cavity during middle ear surgery under an optical microscope. No previous study has assessed the effect of controlled hypotension on inner ear blood flow (IEF) autoregulation in humans receiving propofol or isoflurane anesthesia. In the present study, the IEF autoregulation was determined using laser Doppler flowmetry in combination with transient evoked otoacoustic emissions (TEOAEs) during controlled hypotension with sodium nitroprusside in 20 patients randomly anesthetized with propofol or isoflurane. A coefficient of IEF autoregulation (Ga) was determined during controlled hypotension, with a Ga value ranging between 0 (no autoregulation) and 1 (perfect autoregulation). During controlled hypotension with propofol, IEF remained stable (1%+/-6%; P > 0.05) but decreased by 25%+/-8% with isoflurane (P < 0.05). The Ga was higher during propofol anesthesia (0.62+/-0.03) than during isoflurane anesthesia (0.22+/-0.03; P < 0.0001). Under propofol anesthesia, there were individual relationships between TEOAE amplitude and change in IEF in four patients. Such a correlation was not observed under isoflurane anesthesia. These results suggest that human IEF is autoregulated in response to decreased systemic pressure. Furthermore, isoflurane has a greater propensity to decrease cochlear autoregulation and function than propofol. IMPLICATIONS: The present study shows that inner ear blood flow is autoregulated under propofol, but not isoflurane, anesthesia during controlled hypotension in humans during middle ear surgery. Further studies are needed to explore the postoperative auditory functional consequences of the choice of the anesthetic drug used in middle ear surgery.

Effect of anesthesia on transient evoked otoacoustic emissions in humans: a comparison between propofol and isoflurane.

The influence of general anesthesia (GA) on auditory brainstem responses (ABRs) has been widely studied in humans whereas few studies have been devoted as yet to its effect on cochlear micromechanical properties. This study was aimed at evaluating: (1) the effect of GA on transient evoked otoacoustic emissions (TEOAEs) in humans (n=10), and (2) to compare the effects induced by two different anesthetic agents: propofol (n=5) and isoflurane (n=5). The TEOAEs were continuously monitored together with hemodynamic patterns describing various measures of blood pressure. (1) The GA induced a decrease in TEOAE amplitude and TEOAE amplitude was significantly correlated with the hemodynamic patterns. (2) Both anesthetic agents were responsible for a decrease in TEOAE during the first 20 min of recording. Under propofol, TEOAE amplitude increased after 20 min whereas under isoflurane TEOAEs continued to decrease. Under propofol, TEOAE amplitude was correlated with blood pressure changes in a highly significant manner, whereas under isoflurane TEOAE levels were completely independent of such hemodynamic patterns. These results infer that (1) the GA induced a decrease in TEOAE amplitude, and that (2) TEOAE changes induced by propofol could depend on the concomitant hemodynamic changes whereas isoflurane could be responsible for TEOAE changes depending on both, hemodynamic changes and its own pharmacological properties.

Is the presence of transient evoked otoacoustic emmissions in ears with acoustic neuroma significant?

One hundred sixty-eight patients admitted for acoustic neuroma removal were involved in this study. In all cases, the size of the tumor and the presence or absence of tinnitus and vertigo or dizziness were evaluated. Investigated functional procedures included bilateral measures of pure-tone audiometry (PTA), auditory brainstem response (ABR), electronystagmography (ENG), and transient evoked otoacoustic emissions (TEOAEs). Thirty-five patients (21%) had normal preoperative TEOAEs in the affected ear, whereas 133 patients (79%) failed to show reproducible responses. The aims of this study were 1. to evaluate what distinguishes patients with preoperative TEOAEs in the pathological ear (group A) from those who had no TEOAE (group B); and 2. to determine in cases of attempted hearing preservation whether preoperative TEOAE presence in the neuroma ear (group C) was predictive of postoperative hearing preservation compared with the group of patients without TEOAEs (group D). The presence of vertigo or dizziness was significantly less frequent, the age was lower, and preoperative mean PTA loss in both ears was lower in group A compared with group B. Frequency of the other studied parameters and ABR threshold were similar in both groups. When hearing preservation was attempted, the mean preoperative PTA loss of group C patients was lower in both ears compared with group D. However, postoperative mean PTA loss did not significantly differ in the two groups. In group C, the percentage of hearing preservation (66.6%) was significantly higher than the percentage of deafness (33.4%), whereas in group D the percentage of postoperative preserved audition and deafness did not significantly differ (respectively 44.4% and 55.6%). The findings suggest that 1. TEOAEs in ears with acoustic neuromas are found in younger patients with a lower preoperative mean PTA loss and are accompanied by fewer functional complaints, perhaps because preserved TEOAEs indicate a better preservation of inner ear vasculature; and, 2. along with radiological and electrophysiological investigations, TEOAE presence in the pathological ear could provide an additional criterion or predictive factor for the successful outcome of attempted hearing-conservation surgery in ears with acoustic neuromas.

Cochleovestibular afferent pathways of trapezius muscle responses to clicks in human.

Brief intense clicks cause short-latency cervical muscles microcontractions which are supposed to be of vestibular origin. Averaging these microcontractions allows myogenic vestibular evoked potentials (MVEP) to be obtained. MVEP from the trapezius muscles were investigated in normal subjects, cochleovestibular nerve-damaged patients and patients with a vestibular or a cochlear lesion. Muscular responses were recorded on right and left trapezius by averaging from surface electrodes following right and left monaural 100 dB hearing level click stimulation. In normal subjects, responses to monaural stimuli were bilateral, of equal amplitude and latency in left and right trapezia. Normal response consisted of four consecutive waves, labelled p13, n23, p32 and n40 according to their polarity (p, positive; n, negative) and mean peak latency in msec. In total unilateral cochleovestibular damaged patients, auditory stimulation of the affected side gave no MVEP either ipsilateral or contralateral to the stimulation. In the case of selective cochlear lesion, stimulation of the affected side gave MVEP which was present on ipsilateral and contralateral trapezius muscles. The four successive waves were present with a normal latency; however, amplitude was lower than that obtained after stimulation of the healthy ear. In the case of selective vestibular lesion, the four waves of MVEP were again present with normal latency but with reduced amplitude. Responses were present on both the ipsilateral and contralateral trapezius muscle. It is concluded that normal MVEP recorded on the trapezius muscles are bilateral and consist of four waves, the amplitude of which could depend on the simultaneous stimulation of both cochlear and vestibular afferents. In the case of unilateral cochlear and/or vestibular impairments responses were present on both ipsilateral and contralateral trapezius muscles. Latencies had normal values but amplitudes were reduced. MEVP recorded on trapezius muscles were absent in the case of total cochleovestibular damage.

Myogenic vestibular-evoked potentials in normal subjects: a comparison between responses obtained from sternomastoid and trapezius muscles.

Brief intense clicks cause short latency microcontraction of cervical muscles. Several studies have supported the hypothesis that these microcontractions are of vestibular origin. Averaging these muscular responses enables us to obtain myogenic vestibular evoked potential (MVEP). The receptor of these responses is thought to be the saccule, afferent pathways being the vestibular nerve and efferent pathways the vestibulospinal tract. However, discrepancies are reported with regard to results obtained in healthy subjects: some authors obtained symmetrical response to monaural clicks whereas others obtained responses of greater amplitude on the muscle ispilateral to stimulation. These discrepancies may be due to the presence of different recording sites (inion, sternomastoid or trapezius muscles). The aim of this study was to clarify MVEP results in healthy subjects, using a simple non-traumatic method, and to compare the results obtained on sternomastoid (SM) and trapezius muscles (TRP). Sixteen normal hearing healthy subjects were involved. Latencies and amplitude of both SM and TRP muscle were reproducible in the same subject. Patterns of response were similar to those obtained in previous studies. Following binaural and monaural stimulations, latencies of MVEP were symmetrical on both muscles and amplitudes tended to be greater on muscles contralateral to stimulation, which conflicts with previous results in the literature. Whatever the type of stimulation, latencies of responses obtained on SM were significantly shorter (mean = -3.8 ms), and amplitudes lower (mean = -7.1 microV), than those obtained on TRP. Binaural stimulation resulted in responses of greater amplitude compared to monaural (mean = 0.45 microV). Given the intrasubject reproducibility of the responses, these methods allow MEVP to be recorded in a standardized and reproducible way.

[Rotatory impulse test does not replace caloric tests]. / L'épreuve rotatoire impulsionnelle ne remplace pas les tests caloriques.

We sought to determine whether the rotatory impulsional test was capable of exploring the canalar function with sufficient precision to replace the caloric test, as it has been recently affirmed. We first compared the observed preponderance from this test with that measured during a sinusoidal (20 and 4 s) test. We observed that, in the case of a significant preponderance for a given test, there was complete redondance with the preponderance observed with any other test. The rotatory impulsional test does not present any specific advantage compared to other kinetic test as far as the observation of the preponderance phenomenon. We then compared the preponderance with the results of the caloric tests and came to the following conclusions i) the absence of preponderance does not allow us to predict the absence of vestibular deficit, due to the fact that 37% of the deficits were compensated for including acoustic neuroma; ii) the presence of a preponderance does not allow a priori to say whether it is of vestibular, cervical, or central origin and systematic caloric tests shows that almost one fourth of preponderance observed is not associated with unilateral weakness iii) supposing that a clinical argument allow us to conclude as to the probable vestibular origin of a vestibular preponderance, the direction of this preponderance does not allow us to determine which side is involved. In fact, if the undercompensated deficits are 3 times more frequent than overcompensated deficits, the proportion of preponderance not linked to a significant deficit indicates that the probability of encountering a preponderance related to a specific undercompensated deficit is approximately 50%. We thus did not find in the rotatory impulsional test any specific advantage allowing us to predict the laterality of a vestibular lesion.

Sympathetic nerve regulation of cochlear blood flow during increases in blood pressure in humans.

The purpose of this work was to show that regulation of the blood flow to the cochlea by the sympathetic nervous system occurs in humans at the level of the cochlear microcirculation during increases in blood pressure and that its involvement depends on the pressure level. Eight anaesthetized patients undergoing tympanoplasty for hearing disease took part in a pharmacological protocol of stimulation and inhibition of the autonomic nervous system (ANS) to provide variations in systolic blood pressure (BPS) and cochlear blood flow (CBF). The CBF was measured by laser-Doppler flowmetry. Changes in autonomic nerve activity were brought about by changes in baroreceptor activity (BR) initiated by the injection of an alpha adrenergic agent before and after sympathetic and parasympathetic blockade. The CBF variations (delta CBF) were plotted against BPS increases at each stage of the ANS inhibition. The BR diminished significantly after alpha blockade, after alpha and beta blockade, and after alpha and beta blockade and atropine, by 50% (P < 0.01), 29% (P < 0.05), and 95% (P < 0.001) respectively. The BPS increased significantly (P < 0.01) by 36 (SD 9)%, 47 (SD 1)%, and 67 (SD 16)% respectively. The CBF response to an increase in BPS exhibited two opposing variations in the patients: CBF decreased significantly in one group, and increased significantly in the other group. In both groups, delta CBF decrease and delta CBF increase, respectively, were significant after ANS blockade; even so the decrease and increase, respectively, levelled off at BPS around 160 mmHg before ANS blockade. For BPS below 160 mmHg, correlations between delta CBF and BPS were significant before inhibition and after inhibition of ANS. For BPS below 160 mmHg, BPS and delta CBF were not correlated before inhibition of ANS, and were significantly correlated after inhibition of ANS. For BPS below 160 mmHg, CBF response to the BPS increase was the same before and after ANS blockade, i.e. ANS control did not predominate: even so, for BPS above 160 mmHg, the CBF response to BPS increase was different before and after ANS blockade: CBF varied significantly after ANS blockade as it varied for BPS below 160 mmHg, while it remained constant before ANS blockade that elicited ANS control of CBF. In conclusion, sympathetic nerve regulation via its vasomotor tone at the level of cochlear microcirculation occurred markedly when the blood pressure was above 160 mmHg; the autonomic nervous system would appear to control the cochlear blood flow against large variations in blood flow in response to hypertensive phenomena.

Development of cochlear active mechanisms in humans differs between gender.

Despite onset of function early during the third term of gestation, the human auditory system demonstrates continued maturation, thought previously to occur primarily at the neural level. The electromotile properties of outer hair cells appear to contribute substantially to hearing sensitivity and frequency selectivity and lead to the generation of otoacoustic emissions (OAEs). This report demonstrates continued development of cochlear active mechanisms (i.e. end-organ level) after onset of cochlear function, as reflected by OAEs. Significant gender differences also are reported, corresponding to recently observed intersex differences in cochlear length and precursory to gender differences observed in the adult.