B Napolitano

Vestibular compensation: analysis of postural re-arrangement as a control index for unilateral vestibular deficit.

&NA; Patients with an acute unilateral vestibular lesion show an impaired balance control.The initial presentation is vertigo followed by postural instability; but with time, the global balance functions can be completely restored by a process called vestibular compensation. The aim of our study was to evaluate short and long‐term variations of postural parameters in 20 patients affected by vestibular neuritis (VN), and to compare these patients to 20 normal individuals using computerized static posturography (CSP) along with patient feedback throughout the spectral frequency analysis. This analysis showed in patients with no residual dizziness a frequency shift of body sway from low to middle frequencies as a probable expression of the compensatory strategies used by the central nervous system. On the other hand, patients with persistence of postural instability did not show any frequency shift. Our results seem to provide an early index of a proper occurring compensation so that we can adjust therapeutic protocols according to each patients functional modifications.

Early and Phasic Cortical Metabolic Changes in Vestibular Neuritis Onset

Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [18F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients’ cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients’ subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about early, fast-changing, and complex cortical responses to pathological vestibular unbalanced processing.

The AESOP robot system for video-assisted rigid endoscopic laryngosurgery

Surgeons may occasionally encounter difficulty in visualizing the whole larynx with a direct laryngoscope. In such cases, rigid endoscopic laryngosurgery using a direct laryngoscope is an optimal solution. Multidirectional examination of the larynx using rigid endoscopes during direct laryngoscopy, leads to better control and management of the ventricle, inferior surface of the vocal fold and subglottis, and the anterior commissure. Currently, 0°, 30°, 70° and 120° angled rigid telescopes are used worldwide. Our experience in telescopic endolaryngeal surgery provided us the opportunity to work with AESOP 3000 (automated endoscope system for optimal positioning), coupling a robotic arm to a rigid endolaryngeal telescope. The use of this device allows the surgeon to control the field of view and operate with both hands. A total of 20 patients presenting a laryngeal lesion were randomly selected and included in this study undergoing a robot-assisted procedure. Three of 20 patients presented a difficult laryngeal exposure with direct laryngoscopy due to a rigid, short neck (1 male, 1 female) and prominent teeth (1 male). We used Karl Storz Hopkins II long rigid endoscopes having 0°, 30° and 70° direction of view, a Storz Xenon 300 cold light, a Storz Tricam SL camera, the Kleinsasser direct laryngoscope. The instruments we used are all commercially available for microlaryngeal surgery and included upward curved instruments in case of difficult laryngeal exposure. The operative equipment was the same for all procedures. We evaluated the acquisition of skills in controlling the AESOP 3000, the feasibility of a single surgeon performing procedures with this machine, and any advantages that it might offer to endolaryngeal surgery. The use of robotic devices improves the precision of surgical procedures, offering surgeons a more comfortable working position, particularly for longer procedures, and without an assistant to hold the camera.

Posturography frequency analysis of sound-evoked body sway in normal subjects.

Sound-evoked activation of the vestibular system has been suggested for a long time, and myogenic potentials have been recorded at the level of different muscular groups while a high intensity sound was applied. The aim of this study was to analyse sound-evoked postural responses in normal subjects and to correlate them with the activation of the vestibular system. Body sway was measured by posturography and elaborated through spectral frequency analysis in 40 healthy volunteers in the basal condition and after applying a sound stimulus monoaurally. Spectral frequency analysis results showed a significant increase, in presence of stimulus, of body sway at low and middle frequencies only on the lateral plane and in the closed-eyes condition. As it seems that these frequency ranges are mainly under vestibular control, our results suggest that sound activates specifically the vestibular system, and posturography during sound stimulation represents an alternative approach to assess vestibular function.

Experimental and clinical aspects of the efferent auditory system

The discovery of active mechanisms in the cochlea and the efferent auditory pathways from the brain to the cochlea demonstrated the existence of a modulation of the auditory input in the central nervous system (CNS). Otoacoustic emissions (OAEs) are weak signals that can be recorded in the ear canal and are considered a byproduct of an active process from the outer hair cells (OHCs) to the basilar membrane. The efferent auditory system plays an inhibitory role on the activity of OHCs; its stimulation reduces auditory nerve response, basilar membrane motility and OAEs amplitude. Indirect stimulation by contralateral sound is also inhibitory; a reduction of OAEs amplitude can be recorded and such an effect disappears after olivocochlear bundle section. The efferent system seems to play a role in detection of signals in noise, protection in noise-induced cochlear damage, development of hearing and processing of complex auditory signals. With respect to clinical application, OAEs suppression after contralateral auditory stimulation seems to be the only objective and non-invasive method for evaluation of the functional integrity of the medial efferent system, and, therefore, for evaluation of the structures lying along its course, at least up to the level of inferior colliculi.

Connexin 26 (GJB2) mutations as a cause of the KID syndrome with hearing loss.

KID syndrome (MIM 148210) is an ectodermal dysplasia characterized by the occurrence of localized erythematous scaly skin lesions, keratitis and severe bilateral sensorineural deafness. KID syndrome is inherited as an autosomic dominant disease, due to mutations in the gene encoding gap junction protein GJB2 (connexin 26, Cx26). Cx26 is a component of gap junction channels in the epidermis and in the stria vascularis of the cochlea. These channels play a role in the coordinated exchange of molecules and ions occurring in a wide spectrum of cellular activities. In this paper we describe two patients with Cx26 mutations cause cell death by the alteration of protein trafficking, membrane localization and probably interfering with intracellular ion concentrations. We discuss the pathogenesis of both the hearing and skin phenotypes.

P6 acupressure effectiveness on acute vertiginous patients: a double blind randomized study.

OBJECTIVES The purpose of this study was to evaluate the effectiveness of P6 acupressure on vertigo and neurovegetative symptoms, its possible interference with vestibular-ocular reflex (VOR), and its clinical usefulness during acute vertigo. MATERIALS AND METHODS Two hundred and four patients, either affected by acute vertigo (n=124) or undergoing labyrinth stimulation (n=80), were randomly divided in two homogeneous groups: an experimental group A and a placebo group B. Each patient rated severity of vertigo and neurovegetative symptoms on a visuo-analogue scale ranging from 0 to 10, before and after bilateral placement of a P6 device. The latter was placed on the P6 acupressure point (appropriate placement) in Group A patients or on the dorsal part of the carpus (inappropriate placement) in the Group B patients. Furthermore, qualitative and quantitative nystagmus parameters were collected via recorded video-oculoscopy and electronystagmography. RESULTS Eighty-five percent of Group A patients reported improvement of symptoms, which was significant for neurovegetative symptoms, but not for vertigo. In contrast, only 11% of the Group B patients reported improvement. VOR analysis did not show any significant variation of qualitative and quantitative nystagmus variables. CONCLUSIONS This study demonstrated that the P6 device is effective in improving neurovegetative symptoms in patients affected by spontaneous and provoked vertigo, without any interference with VOR. Given the low cost and lack of side-effects of the P6 device, its routine application is suggested for acute vertigo and during labyrinth stimulation.

Paroxysmal positional vertigo in skeet shooters and hunters

Paroxysmal positional vertigo (PPV) is a high prevalence vestibular end organ disorder due to the detachment of the utricular otoconia floating in the posterior or lateral semicircular canal. In the majority of cases the etiology of PPV is unknown and it may follow viral infections, vascular disorders and head trauma. This report presents six cases (out of 520 diagnoses of PPV) of PPV following repeated training sessions of skeet shooting or gun shooting during animal hunting. The transmission of impulsive and vibratory energy from the shoulder to the cervical spine and the subsequent minimal whiplash injury ipsilateral to the side where the gun is placed on the shoulder may be considered to be responsible of the otoconia detachment.

Dual-energy X-ray absorptiometry analysis of body composition in patients affected by OSAS

Obstructive sleep apnoea syndrome (OSAS) is a disorder characterized by recurrent episodes of apnoea. This study evaluates the body composition in OSAS patients compared to normal weight, pre-obese and obese subjects. Body composition has been measured by dual-energy X-ray absorptiometry in the whole body and in three different body regions. Abdominal region revealed no significant differences in fat mass percentage between patients and controls and no correlation between fat mass percentage and severity of OSAS. At the level of oral region, OSAS patients showed a significant decrease of fat free mass compared to control groups. At the level of neck region, OSAS patients showed a significant increase of fat mass compared to control groups and a significant correlation between the neck fat mass percentage and severity of OSAS. Regional fat distribution constitutes a risk factor for OSAS and a prognostic factor for severity of OSAS.

Recurrent paroxysmal positional vertigo related to oral contraceptive treatment.

Benign paroxysmal positional vertigo (BPPV) is a high-prevalence vestibular end-organ disorder caused by the detachment of utricular otoconia which float in the posterior or lateral semicircular canal. In the majority of cases the etiology of BPPV is unknown and it may follow viral infection, vascular disorders or head trauma. BPPV may be recurrent, with some authors demonstrating a correlation between recurrence and female gender. We report herein on ten cases (out of 289 diagnoses of BPPV) of recurrent idiopathic BPPV, occurring in healthy women receiving oral contraceptive treatment, which ceased after treatment suspension. It has been hypothesized that the impaired water and electrolyte balance, the variations of endolymphatic pH and the impairment of glucose or lipid metabolism induced by oral contraceptive treatment may cause otoconial degeneration and subsequent otoconia detachment and BPPV. The rarity of the finding (10/289) could account for the poor attention paid to the hormonal pathogenesis of BPPV.