Marco Manfrin

New insights into vestibular-saccade interaction based on covert corrective saccades in patients with unilateral vestibular deficits

In response to passive high-acceleration head impulses, patients with low vestibulo-ocular reflex (VOR) gains often produce covert (executed while the head is still moving) corrective saccades in the direction of deficient slow phases. Here we examined 23 patients using passive, and 9 also active, head impulses with acute (< 10 days from onset) unilateral vestibular neuritis and low VOR gains. We found that when corrective saccades are larger than 10°, the slow-phase component of the VOR is inhibited, even though inhibition increases further the time to reacquire the fixation target. We also found that 1) saccades are faster and more accurate if the residual VOR gain is higher, 2) saccades also compensate for the head displacement that occurs during the saccade, and 3) the amplitude-peak velocity relationship of the larger corrective saccades deviates from that of head-fixed saccades of the same size. We propose a mathematical model to account for these findings hypothesizing that covert saccades are driven by a desired gaze position signal based on a prediction of head displacement using vestibular and extravestibular signals, covert saccades are controlled by a gaze feedback loop, and the VOR command is modulated according to predicted saccade amplitude. A central and novel feature of the model is that the brain develops two separate estimates of head rotation, one for generating saccades while the head is moving and the other for generating slow phases. Furthermore, while the model was developed for gaze-stabilizing behavior during passively induced head impulses, it also simulates both active gaze-stabilizing and active gaze-shifting eye movements.NEW & NOTEWORTHY During active or passive head impulses while fixating stationary targets, low vestibulo-ocular gain subjects produce corrective saccades when the head is still moving. The mechanisms driving these covert saccades are poorly understood. We propose a mathematical model showing that the brain develops two separate estimates of head rotation: a lower level one, presumably in the vestibular nuclei, used to generate the slow-phase component of the response, and a higher level one, within a gaze feedback loop, used to drive corrective saccades.

From CT scanning to 3D printing technology: a new method for the preoperative planning of a transcutaneous bone-conduction hearing device

SUMMARY The aim of the present study was to assess the feasibility and utility of 3D printing technology in surgical planning of a transcutaneous bone-conduction hearing device (Bonebridge®) (BB), focusing on the identification of the proper location and placement of the transducer. 3D printed (3DP) models of three human cadaveric temporal bones, previously submitted to CT scan, were created with the representation of a topographic bone thickness map and the sinus pathway on the outer surface. The 3DP model was used to detect the most suitable location for the BB. A 3DP transparent mask that faithfully reproduced the surface of both the temporal bone and the 3DP model was also developed to correctly transfer the designated BB area. The accuracy of the procedure was verified by CT scan: a radiological marker was used to evaluate the degree of correspondence of the transducer site between the 3DP model and the human temporal bone. The BB positioning was successfully performed on all human temporal bones, with no difficulties in finding the proper location of the transducer. A mean error of 0.13 mm was found when the transducer site of the 3DP model was compared to that of the human temporal bone. The employment of 3D printing technology in surgical planning of BB positioning showed feasible results. Further studies will be required to evaluate its clinical applicability.The aim of the present study was to assess the feasibility and utility of 3D printing technology in surgical planning of a transcutaneous boneconduction hearing device (Bonebridge®) (BB), focusing on the identification of the proper location and placement of the transducer. 3D printed (3DP) models of three human cadaveric temporal bones, previously submitted to CT scan, were created with the representation of a topographic bone thickness map and the sinus pathway on the outer surface. The 3DP model was used to detect the most suitable location for the BB. A 3DP transparent mask that faithfully reproduced the surface of both the temporal bone and the 3DP model was also developed to correctly transfer the designated BB area. The accuracy of the procedure was verified by CT scan: a radiological marker was used to evaluate the degree of correspondence of the transducer site between the 3DP model and the human temporal bone. The BB positioning was successfully performed on all human temporal bones, with no difficulties in finding the proper location of the transducer. A mean error of 0.13 mm was found when the transducer site of the 3DP model was compared to that of the human temporal bone. The employment of 3D printing technology in surgical planning of BB positioning showed feasible results. Further studies will be required to evaluate its clinical applicability.

Validation of the Italian Version of the Dizziness Handicap Inventory, the Situational Vertigo Questionnaire, and the Activity-Specific Balance Confidence Scale for Peripheral and Central Vestibular Symptoms

Neurophysiological measurements of the vestibular function for diagnosis and follow-up evaluations provide an objective assessment, which, unfortunately, does not necessarily correlate with the patients’ self-feeling. The literature provides many questionnaires to assess the outcome of rehabilitation programs for disequilibrium, but only for the Dizziness Handicap Inventory (DHI) is an Italian translation available, validated on a small group of patients suffering from a peripheral acute vertigo. We translated and validated the reliability and validity of the DHI, the Situational Vertigo Questionnaire (SVQ), and the Activities-Specific Balance Confidence Scale (ABC) in 316 Italian patients complaining of dizziness due either to a peripheral or to a central vestibular deficit, or in whom vestibular signs were undetectable by means of instrumental testing or clinical evaluation. Cronbach’s coefficient alpha, the homogeneity index, and test–retest reproducibility, confirmed reliability of the Italian version of the three questionnaires. Validity was confirmed by correlation test between questionnaire scores. Correlations with clinical variables suggested that they can be used as a complementary tool for the assessment of vestibular symptoms. In conclusion, the Italian versions of DHI, SVQ, and ABC are reliable and valid questionnaires for assessing the impact of dizziness on the quality of life of Italian patients with peripheral or central vestibular deficit.

Severe to profound deafness may be associated with MYH9-related disease: report of 4 patients.

SUMMARY MYH9-related disease (MYH9-RD) is a rare genetic syndromic disorder characterised by congenital thrombocytopenia and is associated with the risk of developing progressive sensorineural hearing loss, nephropathy and presenile cataracts during childhood or adult life. All consecutive patients enrolled in the Italian Registry for MYH9-RD with severe to profound deafness were included in a retrospective study. The study population involved 147 Italian patients with MYH9-RD: hearing loss was identified in 52% of cases and only 4 patients (6%) presented severe to profound deafness at a mean age of 33 years. Deafness was associated with mild spontaneous bleeding in all patients and with kidney involvement in 3 cases. Cochlear implantation was carried out in 3 cases with benefit, and no major complications were observed. Diagnosis was performed about 28 years after the first clinical manifestation of MYH9-RD, which was never suspected by an otolaryngologist. The clinical and diagnostic aspects of 4 patients with severe to profound deafness are discussed with a focus on therapeutic implications.

Development of a novel Italian speech-in-noise test using a roving-level adaptive method: adult population-based normative data

SUMMARY In recent years the increasing development of hearing devices has led to a critical analysis of the standard methods employed to evaluate hearing function. Being too far from reality, conventional investigation of hearing loss based on pure-tone threshold audiometry and on mono/disyllabic word lists, presented in quiet conditions, has been shown to be inadequate. A speech-in-noise test using a roving-level adaptive method employs target and competing signals varying in level in order to reproduce everyday life speaking conditions and explore a more complete sound range. Up to now, only few roving-level adaptive tests have been published in the literature. We conducted a rovinglevel adaptive test in healthy Italian adults to produce new normative data on a language of Latin origin.

I test audiologici adattivi nella valutazione della funzione uditiva: il Signal Reception Threshold (SRT) nei soggetti normoacusici

Speech in noise test is a new type of hearing test that simulates an everyday listening situation in a very realistic way: in order to achieve this goal sentences and masking noise are sent simultaneously to the patient. This makes it possible to obtain reliable information about the level of intelligibility of a patient, that must be considered to make the best choice, whether it is diagnostic or therapeutic. A clinical trial was conducted from June 2011 at our institution: 50 normoacusic volunteers were submitted to a Speech in noise test and it has been obtained a range of values indicative of the level of normoacusia regard to this new kind of test.

Gli impianti cocleari nelle più comuni sindromi genetiche otorinolaringoiatriche: overview della letteratura ed analisi critica

L’incidenza delle sordita congenite e del 3 per mille nati vivi mentre e dell’1 per mille quella dei bambini che sviluppano sordita prima dell’eta scolare. Il 60% delle sordita prelinguali sono dovute a cause ereditarie. Questo tipo di sordita sono di tipo profondo e spesso bilaterale per cui non si puo raggiungere un livello soddisfacente di recupero uditivo utilizzando le protesi tradizionali; per questo motivo si ricorre all’impianto cocleare che ripristina la percezione sonora. In questo lavoro verra riconsiderata la letteratura esistente in merito all’efficacia dell’impianto cocleare come terapia chirurgica delle sordita genetiche sindromiche tenendo presente la rarita delle patologie e quindi il numero esiguo di casi.

Monitoraggio intraoperatorio del nervo facciale negli interventi otorinolaringoiatrici

Il monitoraggio intraoperatorio e una tecnica che consente di controllare la funzionalita del nervo facciale e di ottenere informazioni in tempo reale sull’insorgenza di eventuali traumatismi nel corso di un intervento chirurgico, dove il chirurgo viene avvisato da un allarme sonoro. Dopo un breve accenno al percorso storico che ha portato a tale tecnica, questo lavoro vuole sottolinearne l’importanza ed i relativi vantaggi; vengono inoltre analizzate le caratteristiche tecniche, gli interventi in cui e indicato applicarlo ed i limiti presentati da questo tipo di metodica.

La Sindrome di Alport: focalizzazione degli aspetti otorinolaringoiatrici nell’ambito di una patologia rara

Con questo lavoro si vuole presentare l’andamento clinico del paziente affetto dalla Sindrome di Alport, descrivendone la sintomatologia con particolare approfondimento all’ambito otorinolaringoiatrico. Inoltre si discute della terapia con l’intervento chirurgico di impianto cocleare, i benefici e l’utilita che si possono raggiungere anche con l’ausilio delle tecniche riabilitative. Per una miglior analisi viene presentato un caso della nostra Clinica Otorinolaringoiatrica, sottolineando il fatto che attualmente non sono presenti in letteratura studi clinici o singoli casi di impianto cocleare effettuato in pazienti affetti da Sindrome di Alport.