Vestibular myogenic potentials evoked by air-conducted stimuli at safe acoustic intensity levels retain optimal diagnostic properties for superior canal dehiscence syndrome

Background: Vestibular-evoked myogenic potential (VEMP) is commonly conducted with air-conducted (AC) stimuli whose intensity may exceed the prudential levels of acoustic exposure in susceptible subjects.

Objectives: To determine the diagnostic accuracy of AC VEMP for superior canal dehiscence syndrome (SCDS) at lowered acoustic stimulation levels.

Material and methods: VEMP was tested in 10 SCDS patients and in 10 age/sex matched control subjects. VEMP were recorded on cervical muscles (cVEMP) and extraocular muscles (oVEMP) in response to short AC tone bursts at 500, 1000 and 2000?Hz delivered at 80?dB nHL (103?dB peSPL). Parameters of interest were the response amplitude and the frequency tuning.

Results: VEMP evoked by AC stimuli at safe acoustic stimulation levels did effectively separate SCDS patients from healthy controls. The separation was optimal at all the frequencies tested, however 500?Hz resulted the best VEMP tuning frequency, especially at oVEMP.

Conclusions: Lowering the AC stimulation to the levels compatible with testing of patients susceptible to acoustic exposure didn’t affect the VEMP diagnostic properties for SCDS.

Significance: SCDS may be screened by VEMP even among subjects susceptible for acoustic exposure.     

High-speed digital imaging and electroglottography of tracheoesophageal phonation by Amatsu's method

Background. Our previous findings have indicated that the thyropharyngeal muscles form a retropharyngeal prominence during alaryngeal phonation via the TE fistula. This prominence forms a so-called ‘neoglottis’, which is thought to function as the vibratory source. To better understand the mechanism of TE phonation, we analyzed the vibration of the neoglottis using electroglottography (EGG) and a high-speed digital imaging system. Patients and methods. Two volunteers who use TE phonation for their daily speech communication were subjected to this study. The vibrations of the neoglottis were recorded simultaneously as EGG and high-speed imaging with acoustic signals. Results. The vibrations of the neoglottis, recorded by means of high-speed digital imaging, were exactly synchronized with the waveforms of the acoustic signals and EGG. Conclusions. These results further confirm the neoglottis as the source of vibration during tracheoesophageal (TE) phonation.     

Compensatory mechanisms affect sensorimotor integration during ongoing vocal motor acts in marmoset monkeys

Any transmission of vocal signals faces the challenge of acoustic interferences such as heavy rain, wind, animal or urban sounds. Consequently, several mechanisms and strategies have evolved to optimize signal‐to‐noise ratio. Examples to increase detectability are the Lombard effect, an involuntary rise in call amplitude in response to masking ambient noise, which is often associated with other vocal changes such as call frequency and duration, as well as the animals’ capability of limiting calling to periods where noise perturbation is absent. Previous studies revealed vocal flexibility and various audio‐vocal integration mechanisms in marmoset monkeys. Using acoustic perturbation triggered by vocal behaviour, we investigated whether marmosets are capable of exhibiting changes in call structure when perturbing noise starts after call onset or whether such effects only occur if noise perturbation starts prior to call onset. We show that marmosets are capable of rapidly modulating call amplitude and frequency in response to such noise perturbation. Vocalizations swiftly increased call frequency after noise onset indicating a rapid effect of perturbing noise on vocal motor production. Call amplitudes were also affected. Interestingly, however, the marmosets did not exhibit the Lombard effect as previously reported but decreased call intensity in response to noise. Our findings indicate that marmosets possess a general avoidance strategy to call in the presence of ambient noise and suggest that these animals are capable of counteracting a previously thought involuntary audio‐vocal mechanism, the Lombard effect. These findings will pave the way to investigate the underlying audio‐vocal integration mechanisms explaining these behaviours.     

Diagnosis and Management of Dural Sinus Thrombosis following Resection of Cerebellopontine Angle Tumors

Objective Lateral sinus thrombosis is a potentially devastating but seldom studied complication of cerebellopontine angle (CPA) tumor surgery. Systemic anticoagulation in the early postoperative period has often been avoided due to the potential risks of intracranial hemorrhage. Design Retrospective review. Setting Tertiary referral center. Main Outcome Measures The goal of this study was to identify the frequency, treatment, and outcomes in patients who develop postoperative venous sinus thrombosis following CPA tumor surgery and receive early systemic anticoagulation. Results Of 43 patients with CPA tumors, we report five patients (11.6%) with transverse and/or sigmoid sinus thrombosis following resection of the tumor, four of which were detected on routine early postoperative noncontrast computed tomography (CT) scan. The thrombosis was confirmed in all cases with CT venography or magnetic resonance venography. Affected patients had significantly larger tumors than controls and tended to undergo longer operations. These patients were treated with immediate anticoagulation (intravenous heparin, followed by Coumadin for 6 months) without complication. Conclusion Venous sinus thrombosis is an underrecognized complication of CPA surgery, but it can be diagnosed in the early postoperative period by noncontrast CT imaging. Early postoperative initiation of systemic anticoagulation appears safe and effective to prevent the progression of thrombosis and its consequences.     

Reconstruction of the facial nerve in acoustic neurinoma surgery. juxtapontine–intratemporal nerve graft

Five cases of large acoustic neurinomas (diameter 2.5 cm) with involvement of the facial nerve in the tumour capsule are presented. The preoperative function of the facial nerve was normal. During surgery, in order to achieve a radical tumour removal, the facial nerve was severed juxtapontine. Reconstruction was performed at the same procedure using a 5-6 cm long sural nerve graft. Thus the central juxtapontine stump was joined to the peripheral stump in the facial nerve canal of the petrous bone. After six months, all five patients exhibited a well functioning mimic and a good eyelid function. At the one year control four patients had normal nerve function clinically and one patient still showed asymmetrical mimic.     

Repair sequences in dysarthric conversational speech: A study in interactional phonetics

This paper presents some findings from a case study of repair sequences in conversations between a dysarthric speaker, Chris, and her interactional partners. It adopts the methodology of interactional phonetics, where turn design, sequence organization, and variation in phonetic parameters are analysed in unison. The analysis focused on the use of segmental and prosodic variation found during attempts by Chris to repair a previously identified trouble source. The results indicate that trouble sources were extremely common in the recorded conversations, but that repair attempts were almost always communicatively successful. Analysis of the fragments revealed that repair sequences are often collaborative achievements, with the participant's conversational partners signalling the specific trouble source within a turn, or providing feedback about repair attempts. It was also observed that successful repair attempts were not always simple repetitions of the trouble source, but varied in other linguistic areas. It is suggested that intelligibility repairs should be studied using both experimental and qualitative methods.