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PubMed1997

Intraoperative monitoring of facial nerve antidromic potentials during acoustic neuroma surgery.

The present paper presents monopolar recording of facial nerve antidromic potentials as an alternative technique to facial electromyography for the continuous monitoring of the facial nerve during acoustic neuroma surgery. The investigation involved 22 patients undergoing acoustic neuroma surgery via a retrosigmoid approach (tumour sizes ranging from 5 to 28 mm). Bipolar electrical stimulation of the marginalis mandibulae was performed to elicit facial nerve antidromic potentials. Stimulus intensity ranged from 2 to 6 mA with a delivery rate of 7/sec. A silver wire monopolar electrode positioned intracranially on the proximal portion of the acoustic facial bundle was used to record antidromic potentials. To define the specific origin of the action potentials and acquire normative data, monopolar and bipolar recordings of facial nerve antidromic potentials were performed in 15 subjects undergoing retrosigmoid vestibular neurectomy for Meniere's disease. The average facial nerve antidromic potential latency was 4.2 (+/- 0.6) msec in subjects with acoustic neuroma and 3.3 (+/- 0.2) msec in subjects with Meniere's disease. Facial nerve antidromic potentials furnished near real-time information about intraoperative facial nerve damage and postoperative facial nerve function during acoustic neuroma surgery. Facial nerve antidromic potentials may provide additional information to conventional EMG. They allow the use of endplate blockers, yield quantitative estimation of facial nerve conduction properties in terms of amplitude and latency, and allow actual continuous monitoring of the facial nerve.

Adult↗

PubMed1982

Identification of serious hearing loss with acoustic reflex data. Clinical experience with some new guidelines.

The acoustic stapedial reflex was activated by a broad-band noise signal for 326 adult subjects. Two groups were formed on the basis of pure-tone audiometry findings. Two hundred and four subjects were normal hearers or showed, at most, a mild hearing loss with a pure-tone average (500, 1000, 2000, and 4000 Hz) of less than 35 dB HL. One hundred and twenty-two subjects showed a serious hearing sensitivity impairment with a pure-tone average of 35 dB HL or greater. These acoustic reflex data were then applied prospectively in the identification of hearing impairment. Hearing sensitivity status was accurately differentiated in over three-fourths of the population. Serious hearing loss was invariably found for subjects with acoustic reflex threshold levels equal to or greater than 110 dB SPL, whereas it was effectively ruled-out by acoustic reflex thresholds in the 60 through 80 dB SPL range. The proportion of subjects with clinically significant hearing impairment is described for intermediate acoustic reflex threshold levels. These guidelines are offered as a feasible first step in clinical differentiation of hearing sensitivity status.

Adult↗

PubMed1997

Improved intensity coding at faster click-rates within the acoustic reflex pathway.

This investigation was designed to study the effect of click repetition rates on the slopes of the ipsilateral acoustic reflex growth functions. Sixteen normal female subjects within the age range 20 to 26 years participated in the study. Following the determination of ipsilateral acoustic reflex thresholds at the click repetition rates of 50, 100, 150, 200, 250 and 300 clicks/sec, reflex amplitudes were measured at 5 and 10 dB above the threshold values. The amplitudes of the acoustic reflex grew more rapidly at higher click rates, resulting in steeper slopes of the acoustic reflex growth functions. These results suggest better coding of intensity at higher click repetition rates within the ipsilateral acoustic reflex pathway.

Adult↗

PubMed2006

Use of the acoustic impulse-response technique for the nondestructive assessment of Manchego cheese texture.

Manchego cheese pieces were hit with an impact probe and the acoustic response was recorded, analyzed, and used to assess the textural characteristics of the cheese pieces. The textural parameters measured by traditional instrumental methods increased during ripening, although the pattern of the increase was different for different batches. For the 2 acoustic impact probes used in this study, a change in the frequency spectrum took place as cheese matured, increasing higher frequencies and the energy content. Multiple linear regression (MLR) and partial least square regression (PLSR), considering the acoustical variables extracted from the spectrum, allowed for a good estimation of cheese texture. The textural characteristics of the cheese surface and in particular the maximum force in compression experiments (R(2) > 0.937 for MLR and R(2) > 0.852 for PLSR) were accurately predicted by the acoustic method; however, the texture of the central layers of the cheese are poorly assessed (R(2) < 0.720). The results obtained show the feasibility of using acoustic systems to assess Manchego cheese texture, aiding its classification.

Acoustics↗

PubMed2002

The facial nerve in medial acoustic neuromas.

OBJECT: Functional results after surgery for acoustic neuromas that have little or no growth within the internal auditory canal are controversial, because these medial tumors can grow to a considerable size within the cerebellopontine angle (CPA) before symptoms occur. METHODS: A prospective study was designed to evaluate the surgical implications of the course of the facial nerve within the CPA on medial acoustic neuromas. This study included a consecutive series of 22 patients with medial acoustic neuromas (mean size 32 mm, range 17-52 mm) who underwent surgery via a suboccipitolateral approach between 1997 and 2001. All patients underwent pre- and postoperative magnetic resonance imaging and preoperative electromyography (EMG). Evaluation was based on continuous intraoperative EMG monitoring and video recordings of the procedure. All patients were reevaluated at a mean of 19 months (6-50 months) postsurgery. Preoperative evaluation of facial nerve function revealed House-Brackmann Grade I in six, Grade II in 14, and Grade III in two patients. During surgery a distinct splitting of the nerve at the root exit zone through its intracisternal course was seen in eight patients and documented by selective electrical stimulation. The facial nerve was separated into a smaller portion that ran cranially and parallel to the trigeminal nerve, and a larger portion on the anterior tumor surface. Both components joined anterior to the porus without major spreading of the nerve bundle. In two cases the nerve was found on the posterior surface of the cranial tumor. In one case the facial nerve entered the porus of the canal at its lower part, obtaining the expected anatomical position proximally within the middle portion of the canal. An anterior cranial, middle (five cases each), or caudal course (two cases) was seen in the remaining patients. After surgery, facial nerve function deteriorated in most cases; on follow-up evaluation House-Brackmann Grade I was found in 11, Grades II and III in 10, and Grade V in one patient. CONCLUSIONS: The facial nerve requires special attention in surgery for medial acoustic neuromas, because an atypical course of the nerve can be expected in the majority of cases. A split course of the nerve was found in 36% of the cases presented. Meticulous use of intraoperative facial nerve stimulation and continuous monitoring ensures facial nerve integrity and offers good functional results in patients with medial acoustic neuromas.

Adult↗

PubMed1989

Temporal integration of acoustic and cutaneous stimuli shown in the blink reflex.

Temporal integration of pairs of brief blink-eliciting acoustic and cutaneous stimuli was investigated to determine if there was integration of stimuli from different modalities. Reflexes elicited by a tone burst or by a brief electrical shock to the supraorbital nerve followed by a second tone burst or shock at short stimulus onset asynchronies (SOAs) were larger and faster than control reflexes elicited by a single stimulus identical to the lead stimulus of the stimulus pairs. Reflex amplitude was augmented at longer SOAs where there was no effect on latency. Temporal integration was evident for all stimulus pairs, showing that it is due, at least in part, to processes that occur outside specific sensory pathways. Heterogeneous stimulus pairs produced greater reflex enhancement than did homogeneous stimulus pairs. This finding was examined further in Experiment 2, which showed that reflex enhancement with pairs of acoustic pulses was unaffected by the frequency of the second stimulus, suggesting that sensory masking was not acting to suppress reflex expression with acoustic pulse pairs. Integration of reflexogenic acoustic stimuli shown in the blink reflex is restricted to shorter intervals than is integration of acoustic stimuli shown by psychophysical procedures, suggesting that the two methods reflect different aspects of stimulus processing. Integration of reflexogenic stimuli may result from summation of activity associated more directly with reflex expression than with perceptual awareness.

Acoustic Stimulation↗

PubMed1995

[Precision and problems in interpretation of acoustic rhinometry in cases of nasal mass lesion].

Precision and problems in interpretation of results obtained by acoustic rhinometry (AR) in cases of mass lesion in the nasal cavity were evaluated with two models, a simple tubal model and a model based on the cast of a cadaver's nasal cavity (cadaver model), and with a human subject. A simple tubal model of 2 cm inside diameter was used. Spherical claies with volumes of 1, 2, 3, and 3.5 cm3, located at same point in the tube, were measured by AR, and a high correlation was found between the clay volume calculated by AR and the real volume of the clay (r = 0.996). But the peak of decrease on the acoustic curve caused by clay was seen a bit posterior to the point where it was actually located. In the entire segment posterior to the peak on the acoustic curve, the value of the area was shown to be smaller than the value of the control. And the large the volume of clay, the greater the degree of decrease in this segment. In the study using the cadaver model, a pill (0.3 cm3) was put at nine sites in the nasal cavity, and AR was performed in each case. The results were compared with the control curve. The decrease in the area on the acoustic curve corresponding to the site of pill placement was recognized, as in the simple tubal model study, and a decrease in the area in the posterior segment of the acoustic curve was also observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustics↗

PubMed1999

[Evaluation of hearing by studying acoustic distortion products in noise-induced hearing loss].

In this work, the Authors want to verify the possibility of an objective method of cochlear function evaluation in subjects affected by chronic acoustic trauma, through the study of the acoustic distortion products. Undertaking 46 subjects, the researchers have demonstrated a direct correlation between the tonal acoustic threshold and that of the distortion products. This method was able to show the useful indications of an objective evaluation of acoustic capacity in non collaborating subject. Because of the large variability of intensity of the distortion products and their absence when the acoustic threshold is more than 50-60 dB HL, they by themselves, don't permit exact evaluation of the tonal threshold for a given frequency.

Acoustic Stimulation↗

PubMedDate not supplied

[Evaluation of dysarthria with the assistance of acoustic speech analysis in patients with amyotrophic lateral sclerosis].

The aim of the study was to assess dysarthria in ALS subjects using acoustic speech analysis. The study was performed in 47 definite or probable ALS patients aged 29-76 years (mean age 53.7 yr.) and in 30 age and sex matched healthy control subjects. Neurological examination showed 15 dysarthric ALS subjects. Acoustic speech analysis is a quantitative, computer-acoustic method estimating dysarthria and based on assessing of sound distance from speech sound tests. In both group the mean sound distance between chosen sounds was compared to a basic pattern and was measured on time-frequency computer acoustic analyses (delta f = 125 Hz, delta T = 9 ms, delta s = 0.5 dB). Our results demonstrated that all sounds were incorrect in all ALS subjects. These abnormalities were significantly increased in the dysarthric ALS subjects. The mean sound distances which separated ALS from control subjects is 0.2 (by Euclidian principle) in 4 out of 5 measured sounds. We suggest that it is possible to detect and measure dysarthria in ALS patients based on the acoustic speech analysis, also in the limb onset ALS subjects.

Adult↗

PubMed2001

Accuracy of acoustic rhinometry.

OBJECTIVES: The objective of this study was to evaluate the ability of acoustic rhinometry (AR) (Rhin2100, Rhinometrics, Lynge, Denmark) to accurately determine the dimensions (cross-sectional areas and volumes) of the curved and complex slit-like geometry of the nasal airway. MATERIALS AND METHODS: A plastic model representing the replicate of a decongested nasal airway was produced by stereolithographic techniques from a 3-D MRI-scan. The exact dimensions of this model was determined from a high resolution CT-scan. Dimensions perpendicular to the curved course of the acoustic pathway were compared with dimensions inferred from parallel sections. The impact of sound loss to the paranasal sinuses and the ability to detect posterior volume changes was tested in the same model. RESULTS: The error in volume determination was < 14% for the MCA and < 8% for the volumes, whereas the error reached 52% for dimensions calculated from parallel sections in the coronal plane. The influence of the simulated maxillary sinuses depend primarily on the size of the ostia and may represent an important source of error for posterior measurements, in particular after decongestion. CONCLUSIONS: The accuracy of acoustically derived dimensions of the 3-D model depend on the orientation of the planes used to calculate the dimensions of the model. Volume estimates based on the smallest cross-sectional areas in points along the acoustic pathway correlate well with acoustically derived volumes, whereas single cross-sectional areas are more susceptible to error. Sound leakage to patent sinus ostia reduce the accuracy of posterior measurements.

Acoustics↗

PubMed1975

Ipsilateral acoustic reflex stimulation in normal and sensorineural impaired ears: a preliminary report.

Ipsilateral acoustic reflex thresholds were measured at 1,000 Hz and 2,000 Hz in 38 subjects with normal hearing and in 107 subjects with a symmetrical sensorineural hearing loss. Acoustic reflex thresholds were approximately six dB better for ipsilateral vs. contralateral stimuli for both subject groups. High ipsilateral reflex thresholds were associated with larger static compliance values in the sensorineural hearing impaired subjects. Reversed reflexes (increasing compliance with muscle contraction) were observed for ipsilateral stimulation in five per cent (two) of the normal hearing subjects, and 23 percent (25) of the sensorineural hearing impaired subjects. The number of reversed reflexes was greater for subjects with higher hearing thresholds and higher ipsilateral acoustic reflex thresholds. The results suggest that quantitative use of the ipsilateral acoustic reflex requires additional research. At present it seems prudent to use ipsilateral acoustic reflex measurements as a qualitative rather than a quantitative tool, e.g. in confirming the status of one middle ear when the other has a conductive hearing loss. However, even this limited role has a considerable clinical potential.

Acoustic Stimulation↗

PubMed2001

[Vowel selection effects on the parameters of acoustic analysis].

OBJECTIVE: To investigate if there is difference about the parameters of acoustic analysis with the different vowel |a|, |i|, |ae| and decide which vowels is best fitted to the acoustic analysis. METHOD: 40 normal and 130 pathologic voice patients accepted acoustic analysis. Each acoustic parameters such as jitter, shimmer, NNE, SDF0, SNR were compared with different vowels. RESULT: Jitter, shimmer, NNE with |i| were much lower than that with |a| and |ae| in normal cases and light hoarseness group. While the acoustic parameters with |i| were much higher than that with |a| and |ae| in moderate and heavy hoarseness group. CONCLUSION: |a| and |ae| were the preferred vowels for normal and light hoarseness group, while the |i| could supply some useful suggestion for the moderate and heavy hoarse patients.

Adolescent↗

PubMed2002

[The development and clinical application of acoustic diagnostic technique in hip joint].

This study aimed to develop a non-invasive diagnostic technique for the measurement of acoustic transmission in hip joints to reflect the dynamic response of the observed structure. This instrument consists of three sub-systems. An stimulation system applied a vibratory force at the sacrum of the test subject. A transduction system included a pair of identical microphones was installed in the tubes of two stethoscopes, which were placed at the greater trochanters on both sides for picking up the acoustic signals transmitting across the hip joints. The data acquisition and analysis system was a portable frequency analyser with a program of dual channel digital filter for measuring the power of acoustic signals in 1/3-octoscn frequency bands. Twenty-seven normal adults, 20 normal pre-school children and 40 normal neonates were recruited for the testing. Coherence function (CF) of the signal and the discrepancy (D) of bilateral hips were measured during the testing. The results from the three groups showed that there was a high coherence of the signals (CF > 0.9) and a small discrepancy (D < 3 dB) between bilateral hips in the frequency range of 200-315 Hz. For normal neonates, the frequency range (160-315 Hz) was wider in which the acoustic signals maintained a high coherence (CF > 0.94) and a smaller discrepancy (D < 2 dB) were observed between bilateral hips. This study has shown that the development of the acoustical diagnostic technique could provide a practical method with objective parameters. The results obtained in this study can offer a base for further investigation of hip disorders, particularly those related to structural abnormalities of hip joints.

Acoustic Stimulation↗

PubMed2003

[The endoscopic technique utilized in removal process of acoustic neuroma by retrosigmoid approach].

OBJECTIVE: Research into the technique and signification of reducing remnant tumor with utilizing endoscopic technique during removal of acoustic neuroma. METHOD: 15 patients proceeded the removal of acoustic tumor through retrosigmoid approach (as routine retrosigmoid-approach operation group, RRSO-G), 11 patients utilized endoscope for inspecting and eliminating remain of tumor during the proceed of the removal of acoustic neuroma through retrosigmoid approach (as retrosigmoid-approach operation combined using endoscope, RSOCE-G), all of them were examined of auditory level, vestibular function, facial nerve function, and MRI before and three months after operation. RESULT: The remain tumor were found in 3 cases of RRSO-G and no any one in RSOCE-G after operation. The rates of auditory and vestibular dysfunction, and facial paralysis have no difference between RRSO-G and RSOCE-G. CONCLUSION: It is one of expedient and safe surgery methods that the acoustic neuroma are removed through the retrosigmoid approach, and some degrees of hearing function are reserved at same time. If the endoscope is utilized during this operation, the rate of tumor remaining and neuroma recrudescing could be reduced evidently. The acoustic neuroma removed through the retrosigmoid approach combining with utilizing endoscope is a worthy method for using widely in otoneurosurgery.

Adult↗

PubMed2003

[Acoustic characteristics of classrooms].

Quality and usefulness of school rooms for transmission of verbal information depends on the two basic parameters: form and quantity of the reverberation time, and profitable line measurements of school rooms from the acoustic point of view. An analysis of the above-mentioned parameters in 48 class rooms and two gymnasiums in schools, which were built in different periods, shows that the most important problem is connected with too long reverberation time and inappropriate acoustic proportions. In schools built in the 1970s, the length of reverberation time is mostly within a low frequency band, while in schools built contemporarily, the maximum length of disappearance time takes place in a quite wide band of 250-2000 Hz. This exceeds optimal values for that kind of rooms at least twice, and five times in the newly built school. A long reverberation time is connected with a low acoustic absorption of school rooms. Moreover, school rooms are characterised by inappropriate acoustic proportions. The classrooms, in their relation to the height, are too long and too wide. It is connected with deterioration of the transmission of verbal information. The data show that this transmission is unequal. Automatically, it leads to a speech disturbance and difficulties with understanding. There is the need for adaptation of school rooms through increase of an acoustic absorption.

Acoustics↗

PubMed2003

Evaluation with acoustic rhinometry of patients undergoing sinonasal surgery.

The purpose of this study is to evaluate the use of Acoustic Rhinometry in assessing surgical outcomes in sinonasal surgery. This prospective study was carried out from January till December 2001. A group of 44 patients who presented with nasal obstruction due to various rhinologic abnormality were examined with acoustic rhinometry pre and post-operatively. They were examined with acoustic rhinometry pre and post decongestion with cocaine and adrenaline. A highly significant correlation existed between minimal cross sectional area (MCA) and the subjective feeling of nasal problem, pre and post surgery. Thus MCA is a valuable parameter to express objectively the nasal patency. The mucovascular component of the nasal cavity plays a major role in the nasal patency as determined in the pre and post-decongestion acoustic rhinometry measurement. Acoustic rhinometry is a good tool to evaluate the nasal patency in cases where sinonasal surgery is considered in correcting the abnormality as well as for the post-operative evaluation.

Adult↗

PubMedDate not supplied

Acoustic energy: a new transfection method for cancer of the prostate, cancer of the bladder and benign kidney cells.

BACKGROUND: Clinical use of gene therapy is limited by the poor efficacy and accuracy of intracellular DNA delivery. Known concepts of DNA transfection have not yet become clinical routine in the treatment of human disorders. We therefore focused on new transfection methods using different forms of acoustic energy as potentially safe and topographically applicable methods for gene delivery in the field of urology. MATERIALS AND METHODS: Three different cell lines (prostatic and urothelial cancer, benign kidney) were transfected by different forms of acoustic energy. The effect of several parameters of electromagnetic shock wave treatment (number and frequency of impulses, energy flow density and plasmid concentration) as well as focused ultrasound on the transfection rate was assessed in a standardized experimental setup. The transfection rate was measured through reporter genes (pEGFP) by FACScan. Transfection by lipofectamine and electroporation served as positive controls. RESULTS: All cell lines were transfectable by acoustic energy. Maximum transfection rate was achieved using focused ultrasound (49.5o%; 200 W, 500 ms, 200 microg/ml DNA). 31.3% of kidney cells were transfected by electromagnetic shock waves (1500 impulses, 200 microg/ml DNA, 0.5 mJ/mm2 energy density, 2 Hz). Plasmid strand breaks were identified as a limiting factor of the transfection rate. CONCLUSION: Transfection by acoustic energy, especially focused ultrasound, can be achieved at a high level in different cell lines. The possible topical application to urological organs and the low level of side-effects make acoustic energy a promising new gene therapy treatment option in urology.

Acoustics↗

PubMed2004

[Enlarged translabyrinthine resection of recurrent acoustic neuroma after suboccipital resection].

OBJECTIVE: To evaluate the technique and the outcome of enlarged translabyrinthine removal of recurrent acoustic neuromas after a suboccipital resection. METHOD: Five patients were proved to have recurrent acoustic neuromas after previous suboccipital removal procedures. Revision surgery was accomplished in these patients using the enlarged translabyrinthine approach by sufficiently removing petrous temporal bone to enlarge exposed sight during the operation. RESULT: The sizes of the recurrent tumors ranged from 2.5 to 4.0 cm. Total removal was achieved in all patients, with no death and other major complications such as intracranial infection and cerebrospinal fluid leakage. The facial nerve function was the same as pre-operative condition. There was no residual tumor showed in CT scans and MRI examinations after operation. The cerebel and brainstem resumed to normal position in each patient. No second recurrences had occurred to date at follow-up of 6 months to 2 years and 7 months. All patients recuperated and came back to work. CONCLUSION: Acoustic neuroma recurs frequently after the suboccipital surgery because there is a residual tumor inside the internal acoustic canal (IAC). The enlarged translabyrinthine approach is the most direct access to acoustic neuroma and the brainstem by which recurrent tumor can be removed is avoided during the second operation. Moreover, it is praisable that there are several advantages such as slight invasion and convenience of facial nerve orientation so as to excellent outcome of facial nerve preservation in the enlarged translabyrinthine surgery.

Aged↗