Downbeat nystagmus: a clinical and pathophysiological review.

Downbeat nystagmus (DBN) is a neuro-otological finding frequently encountered by clinicians dealing with patients with vertigo. Since DBN is a finding that should be understood because of central vestibular dysfunction, it is necessary to know how to frame it promptly to suggest the correct diagnostic-therapeutic pathway to the patient. As knowledge of its pathophysiology has progressed, the importance of this clinical sign has been increasingly understood. At the same time, clinical diagnostic knowledge has increased, and it has been recognized that this sign may occur sporadically or in association with others within defined clinical syndromes. Thus, in many cases, different therapeutic solutions have become possible. In our work, we have attempted to systematize current knowledge about the origin of this finding, the clinical presentation and current treatment options, to provide an overview that can be used at different levels, from the general practitioner to the specialist neurologist or neurotologist.

Evolution of Hyperventilation-Induced Nystagmus in Acute Unilateral Vestibulopathy-Interpretative Model and Etiopathogenetic Hypotheses.

Hyperventilation induces metabolic changes that can elicit nystagmus (hyperventilation-induced nystagmus, HVIN) in various vestibular disorders, revealing vestibular imbalance and bringing out central or peripheral asymmetries. In acute unilateral vestibulopathy (AUVP, namely vestibular neuritis), hyperventilation can induce different patterns of nystagmus (excitatory, inhibitory, or negative), disclosing or modifying existing static vestibular asymmetries through its ability to invalidate compensation or increase peripheral excitability. In this context, we followed the evolutionary stages of HVIN in AUVP across 35 consecutive patients, with the goal of assessing alterations in the oculomotor pattern caused by hyperventilation over time. In the acute phase, the incidence of the excitatory pattern (and the strongly excitatory one, consisting of a reversal nystagmus evoked by hyperventilation) was significantly higher compared to the inhibitory pattern; then, a progressive reduction in the incidence of the excitatory pattern and a concomitant gradual increase in the incidence of the inhibitory one were observed in the follow-up period. Assuming the role of the ephaptic effect and the transient loss of vestibular compensation as opposing mechanisms, i.e., excitatory and inhibitory, respectively, the oculomotor pattern evoked by hyperventilation is the result of the interaction of these two factors. The data obtained allowed us to hypothesize an interpretative model regarding the pathogenetic aspects of responses evoked by hyperventilation and the etiologies of the disease: according to our hypotheses, the excitatory pattern implies a neuritic (viral) form of AUVP; instead, the inhibitory (and negative) one can be an expression of both the neuritic (viral) and vascular forms of the disease.

Pediatric normative data for a novel and fast speech perception test in noise.

OBJECTIVES: Communicating in noisy settings can be difficult due to interference and environmental noise, which can impact intelligibility for those with hearing impairments and those with normal hearing threshold. Speech intelligibility is commonly assessed in audiology through speech audiometry in quiet environments. Nevertheless, this test may not effectively assess hearing challenges in noisy environments, as total silence is rare in daily activities. A recently patented method, known as the SRT50 FAST, has been developed for conducting speech audiometry in noise. This new method enables the acceleration and simplification of free field speech audiometry tests involving competition noise. This study aims to establish normative scores and standardize the SRT50 FAST method as a test for evaluating speech perception in noise in pediatric patients. METHODS: The study included 30 participants with normal hearing, consisting of 11 females and 19 males, ranging in age from 6 to 11 years. A series of speech audiometry tests were conducted to determine the speech reception threshold 50% (SRT50) in competing conditions. This included testing both the fast mode (SRT50 FAST) currently being studied and the traditional method (SRT50 CLASSIC). The SRT50, or Signal to Noise Ratio (SNR) at which 50% of speech recognition occurred, was investigated for both methods. RESULTS: The mean SRT50 FAST test score was -2.69 (SD = 3.15). The dataset exhibited a normal distribution with values ranging from 3.60 to -8.60. Since the scores are expressed in SRT, higher scores indicate poorer performance. We have established a threshold of 3.60 as the upper limit of the normal range, therefore, patients with scores above this threshold are considered to have abnormal results. CONCLUSIONS: This study aimed to establish normative data for the evaluation of free field speech in noise recognition using the SRT50 FAST method in the pediatric population. This method accurately investigates the necessary signal-to-noise ratio for achieving 50% recognition scores with bisyllabic words in a quick manner. The ultimate objective is to employ this test to identify the optimal configuration of hearing rehabilitation devices, particularly for pediatric patients with hearing aids and/or cochlear implants. Additionally, it can be used to assess pediatric patients with unilateral hearing loss.

Evaluation of Cochlear Symptoms in Migraine Patients without Vestibular Migraine and/or Ménière's Disease.

Migraine pathogenic pathways may selectively target the cochlea. A qualitative and quantitative analysis of cochlear symptoms in migraine patients without vestibular migraine and/or Méniere's disease was conducted. We examined 60 consecutive patients with history of cochlear symptoms, including fullness, tinnitus, and hearing loss. Patients were divided into two groups based on migraine history: M (migraine) and nM (no migraine). The incidence of migraine was compared to a homogeneous control group with dysfunctional and inflammatory dysphonia without cochlear symptoms. The type, time of onset, recurrence, bilaterality of symptoms, and hearing threshold were analyzed. The incidence of migraine was significantly higher (p = 0.04) in patients with cochlear symptoms than in the control group. The onset of symptoms is significantly earlier (p < 0.05) in the presence of migraine. The fullness, recurrence, and bilaterality of symptoms are associated with migraine in a statistically significant way (p < 0.05). Pure tone audiometry shows a statistically significant increase in the hearing threshold (500-1000 Hz) in group M. Based on developing findings, cochlear migraine may be considered as a novel clinical entity, like vestibular migraine. It would be the expression, in the absence of vertiginous symptoms, of a selective suffering of the anterior labyrinth by known operating mechanisms of migraine.

Practice of Monitoring Cisplatin-Induced Ototoxicity by Audiology, ENT, and Oncology Specialists: A Survey-Based Study in a Single Italian Medical Center.

Ototoxic drugs can result in hearing loss and tinnitus. Early detection of the ototoxic process can help minimize or prevent these consequences. The American Speech-Language-Hearing Association has provided guidelines for monitoring ototoxicity, whereas Italy has not yet implemented a national monitoring protocol. This study aims to assess the current state of ototoxicity monitoring in patients receiving cisplatin therapy. A self-administered survey has been used to gather information from oncologists, audiologists, and ENT specialists. The research was conducted at Santa Maria della Misericordia hospital in Perugia. Two questionnaires were administered, one to ENT/audiology specialists and another to oncology specialists. Both questionnaires were used to collect information on awareness of chemotherapy-induced ototoxicity. A comprehensive understanding of cisplatin-induced ototoxicity has been widely established (100%). The most commonly reported audiological symptoms by patients were hearing loss (100%) and tinnitus (87.5%). The majority of ENT and audiologists (93.8%) and oncologists (92.9%) expressed the need for a specific ototoxic monitoring program. However, they noted the absence of a well-defined ototoxicity monitoring protocol. A well-established and efficient ototoxic monitoring system facilitates early detection of ototoxic hearing loss and subsequent rehabilitation of inevitable hearing impairment.

Skull-vibration-induced nystagmus test in patients who are candidates for intratympanic gentamicin injection.

Objective: This study aims to evaluate the utility of the skull-vibration-induced nystagmus test (SVINT) in the selection of patients with Ménière's disease (MD) for intratympanic injection of gentamicin. To date the indications for this treatment have been based only on subjective elements. Methods: A retrospective study was performed in 20 patients diagnosed with unilateral MD. SVINT were performed monthly and the evoked responses were evaluated. After 6 months, the results from patients who were candidates for gentamicin treatment (G group) were compared with those who did not need it (nG group). Correlation with Dizziness Handicap Inventory (DHI) score was evaluated. Results: 120 tests were performed. Positive SVINTs were identified in 52 cases (43.3%) and included excitatory nystagmus in 18 (34.7%), inhibitory nystagmus in 28 (53.8%), and atypical pattern in 6 cases (11.5%). A significant increase excitatory nystagmus was recorded in group G (p = 0.00001). Moreover, there was a significant increase in the DHI score in group G compared with the nG group (p < 0.0001) and in patients with evoked excitatory nystagmus. Conclusions: The finding of excitatory nystagmus during SVINTs performed on several occasions in the follow-up prior to intratympanic injection of gentamicin strengthens this therapeutic choice.

Plastic changes induced by muscle focal vibration: A possible mechanism for long-term motor improvements.

Repetitive focal vibrations can induce positive and persistent after-effects. There is still no satisfactory interpretation of the underlying mechanisms. A rationale, which can provide consistency among different results, is highly desirable to guide both the use of the application and future research. To date, interpretive models are formulated to justify the results, depending on the specific protocol adopted. Indeed, protocol parameters, such as stimulus intensity and frequency, intervention time and administration period, are variable among different studies. However, in this article, we have identified features of the protocols that may allow us to suggest a possible common mechanism underlying the effectiveness of focal vibration under different physiologic and pathologic conditions. Since repetitive focal muscle vibration induces powerful and prolonged activation of muscle proprioceptors, we hypothesize that this intense activation generates adaptive synaptic changes along sensory and motor circuits. This may lead to long-term synaptic potentiation in the central network, inducing an enhancement of the learning capability. The plastic event could increase proprioceptive discriminative ability and accuracy of the spatial reference frame and, consequently, improve motor planning and execution for different motor functions and in the presence of different motor dysfunctions. The proposed mechanism may explain the surprising and sometimes particularly rapid improvements in motor execution in healthy and diseased individuals, regardless of specific physical training. This hypothetic mechanism may require experimental evidence and could lead to extend and adapt the application of the "learning without training" paradigms to other functional and recovery needs.

Induction and Cancellation of Self-Motion Misperception by Asymmetric Rotation in the Light.

Asymmetrical sinusoidal whole-body rotation sequences with half-cycles at different velocities induce self-motion misperception. This is due to an adaptive process of the vestibular system that progressively reduces the perception of slow motion and increases that of fast motion. It was found that perceptual responses were conditioned by four previous cycles of asymmetric rotation in the dark, as the perception of self-motion during slow and fast rotations remained altered for several minutes. Surprisingly, this conditioned misperception remained even when asymmetric stimulation was performed in the light, a state in which vision completely cancels out the perceptual error. This suggests that vision is unable to cancel the misadaptation in the vestibular system but corrects it downstream in the central perceptual processing. Interestingly, the internal vestibular perceptual misperception can be cancelled by a sequence of asymmetric rotations with fast/slow half-cycles in a direction opposite to that of the conditioning asymmetric rotations.

Treatment of Far-Advanced Otosclerosis: Stapedotomy Plus Hearing Aids to Maximize the Recovery of Auditory Function-A Retrospective Case Series.

Far-advanced otosclerosis (FAO) refers to severe otosclerosis with scarce auditory functions. The identification of the best method to correctly listen to sound and speech has a large impact on patients' quality of life. We retrospectively analyzed the auditory function of 15 patients affected by FAO who were treated with stapedectomy plus hearing aids independent of the severity of their auditory deficit before surgery. The combination of surgery and hearing aids allowed excellent recovery of the perception of pure tone sounds and speech. Four patients, because of poor auditory thresholds, needed a cochlear implant after stapedectomy. Despite being based on a small sample of patients, our results suggest that stapedotomy plus hearing aids could improve the auditory capacities of patients with FAO independent of their auditory thresholds at T0. The careful selection of patients is fundamental to obtain the best outcomes.

Persistent Postural Perceptual Dizziness in Episodic Vestibular Disorders.

Benign Paroxysmal Positional Vertigo (BPPV), Vestibular Migraine (VM), and Meniere Disease (MD) are among the most common episodic vestibulopathies. Persistent Postural Perceptual Dizziness (PPPD) is a chronic functional vestibular disorder that can arise in patients suffering from one or more of these conditions. We analyzed the role of these vestibular disorders as single or multiple associated comorbidities and as a precipitating condition for PPPD. A total of 376 patients suffering from dizziness with a known history of single or multiple vestibular disorders were preliminarily evaluated. We conducted a careful anamnesis to determine whether the reported dizziness could meet the diagnostic criteria for PPPD. PPPD was diagnosed in 24 cases; its incidence in patients with history of a single comorbidity or multiple vestibular comorbidities was 3.9% and 22.4%, respectively. BPPV, VM, and MD were identified as a precipitating condition in 2.34%, 16.45%, and 3.92%, respectively. BPPV constituted a precipitating condition mainly at the first episode. We observed that the presence of multiple vestibular comorbidities (BPPV, VM, and MD) in patients' clinical history increased the risk of PPPD. VM plays a significant role in representing a precipitating condition for PPPD, both when present individually or in association with the other vestibular disorders.

Critical Issues in the Management of Newborn Hearing Screening in the Time of COVID-19 in Umbria, Italy.

Hearing impairment is the most frequent of the sensorial defects in humans, and if not treated promptly, can severely impair cognitive and spoken language skills. For this reason, a universal newborn hearing screening (UNHS) has been established. The purpose of our study is to examine, by means of a retrospective analysis, the results of the UNHS program in the Umbria region during the spread of COVID-19 (2020-2021), comparing the same data from the years 2011-2012, to understand if the program has improved. Our study has shown how the coverage rate of well born babies' (WB) screening has significantly increased to currently meet the JCIH benchmark. The percentage of WB referrals significantly decreased in 2020-2021, another indicator of the screening program's greater efficiency in Umbria. However, a critical issue has emerged: the percentage of those lost to follow-up is greater than 30%, well above the benchmark. As far as the COVID-19 pandemic has certainly had a significant impact, it is necessary to carefully monitor those who do not access the diagnostic level. To emphasize the importance of a proper screening program, it will be helpful to strengthen the computerized data collection system and create an information network between audiologists, pediatricians and families.

Prevention of Recurrent Benign Paroxysmal Positional Vertigo: The Role of Combined Supplementation with Vitamin D and Antioxidants.

Benign paroxysmal positional vertigo (BPPV) usually has a favorable course, although it is possible to observe BPPV with a high recurrence rate. Previous studies suggested that vitamin D deficiency might affect BPPV recurrences, and oxidative stress might play a complementary role in BPPV pathogenesis. This multicentric trial aimed to evaluate the effectiveness of oral nutritional supplementation with a compound of alpha-lipoic acid, Carnosine, and Zinc (LICA® (Difass International, Coriano (RN), Italy)), vitamins of group B and vitamin D in preventing BPPV recurrences. A total of 128 patients with high recurrence-BPPV were randomized in three arms: Arm 1 consisted of subjects with "insufficient" or "deficient" vitamin D blood levels, treated with daily oral supplementation of LICA®, vitamins of group B and vitamin D3 (800 UI), Arm 2 included BPPV subjects with "sufficient" vitamin D who did not receive any nutritional support, and Arm 3 included subjects with a "sufficient" serum concentration of vitamin D who received supplementation with a compound of LICA® and Curcumin. After six months of follow-up, a significant reduction of BPPV relapses compared to the baseline was found only in Arm 1 (−2.32, 95% CI: 3.41−1.62, p-value < 0.0001). Study results suggested that oral nutritional supplementation with vitamin D3 plus antioxidants can prevent relapses in patients suffering from high recurrence-BPPV.

Adaptive perceptual responses to asymmetric rotation for testing otolithic function.

This study aimed to test the role of the otolithic system in self-motion perception by examining adaptive responses to asymmetric off-axis vertical rotation. Self-movement perception was examined after a conditioning procedure consisting of prolonged asymmetric sinusoidal yaw rotation of the head on a stationary body with hemicycle faster than the other hemicycle. This asymmetric velocity rotation results in a cumulative error in spatial self-motion perception in the upright position that persists over time. Head yaw rotation conditioning was performed in different head positions: in the upright position to activate semicircular canals and in the supine and prone positions to activate both semicircular canals and otoliths with the phase of otolithic stimulation reversed with respect to activation of the semicircular canals. The asymmetric conditioning influenced the cumulative error induced by four asymmetric cycles of whole-body vertical axis yaw rotation. The magnitude of this error depended on the orientation of the head during the conditioning. The error increased by 50% after upright position conditioning, by 100% in the supine position, and decreased by 30% in the prone position. The enhancement and reduction of the perceptual error are attributed to otolithic modulation because of gravity influence of the otoliths during the conditioning procedure in supine and prone positions. These findings indicate that asymmetric velocity otolithic activation induces adaptive perceptual errors such as those induced by semicircular canals alone, and this adaptation may be useful in testing dynamic otolithic perceptual responses under different conditions of vestibular dysfunction.

Inhibition of androgenic pathway impairs encoding of cerebellar-dependent motor learning in male rats.

Cerebellar-dependent learning is essential for the adaptation of motor and no motor behaviors to changing contexts, and neuroactive steroids-mainly referred to as estrogens-may regulate this process. However, the role of androgens in this process has not been established, although they may affect cerebellar physiology. Thus, this study aims to determine whether the activation of androgenic neural pathways may take part in controlling the vestibuloocular (VOR) and optokinetic reflexes (OKR), which depend on a defined cerebellar circuitry. To answer this question, we acutely blocked the activation of androgen receptors (Ars) using systemic administration of the Ars antagonist flutamide (FLUT; 20 mg/Kg) in peripubertal male rats. Then, we evaluated the FLUT effect on general oculomotor performance in the VOR and OKR as well as VOR adaptive gain increases and decreases. We used a paradigm causing fast VOR adaptation that combined in phase/out phase visuo-vestibular stimulations. We found that FLUT impaired the gain increase and decrease in VOR adaptation. However, FLUT altered neither acute nor overtime basal ocular-motor performance in the VOR or OKR. These findings indicate that the activation of androgenic neural pathways participates in phenomena leading to fast VOR adaptation, probably through the modulation of plasticity mechanisms that underlie adaptation of this reflex. Conversely, androgens may not be essential for neural information processing demands in basal ocular-motor reflexes. Moreover, our results suggest that androgens, possibly testosterone and dihydrotestosterone, could rapidly regulate motor memory encoding in the VOR adaptation, acting at both cerebellar and extracerebellar plasticity sites.

OTOPLAN, Cochlear Implant, and Far-Advanced Otosclerosis: Could the Use of Software Improve the Surgical Final Indication?

Cochlear implant surgery in far-advanced otosclerosis can be challenging due to the degenerative process that affects the cochlea. We used OTOPLAN® to plan and define the details of surgery in a patient with such severe alteration of the cochlea that cochlear implant could be contraindicated. A 73-year-old man affected by bilateral far-advanced otosclerosis, previously treated by bilateral stapedotomy, presented 0% of speech discrimination using bilateral hearing aids. A unilateral cochlear implant was planned. The patient underwent radiologic investigation pre-surgery with temporal bone computer tomography, magnetic resonance imaging, and OTOPLAN. Radiology confirmed bilaterally advanced signs of fenestral and cochlear otosclerosis with large osteolytic cavities along the whole cochlea leading to the mixture of endolymph and perilymph. The OTOPLAN identified the alteration of the cochlea in detail. Based on the results of the software, we used a perimodiolar implant on the left ear. No intraoperative or post-operative surgical complications were observed. The patient was checked 6 months after surgery, he did not refer any problems and obtained 75% of speech discrimination at 65 dB. Our case suggests that OTOPLAN is a useful tool in far-advanced otosclerosis because careful planning of the surgery can positively affect the results. Despite the complexity of the anatomy, the software exactly described the real intrasurgical finding. We think that the use of OTOPLAN might improve the surgical indication.

Disruption of self-motion perception without vestibular reflex alteration in ménière's disease.

BACKGROUND: Self-motion misperception has been observed in vestibular patients during asymmetric body oscillations. This misperception is correlated with the patient's vestibular discomfort. OBJECTIVE: To investigate whether or not self-motion misperception persists in post-ictal patients with Ménière's disease (MD). METHODS: Twenty-eight MD patients were investigated while in the post-ictal interval. Self-motion perception was studied by examining the displacement of a memorized visual target after sequences of opposite directed fast-slow asymmetric whole body rotations in the dark. The difference in target representation was analyzed and correlated with the Dizziness Handicap Inventory (DHI) score. The vestibulo-ocular reflex (VOR) and clinical tests for ocular reflex were also evaluated. RESULTS: All MD patients showed a noticeable difference in target representation after asymmetric rotation depending on the direction of the fast/slow rotations. This side difference suggests disruption of motion perception. The DHI score was correlated with the amount of motion misperception. In contrast, VOR and clinical trials were altered in only half of these patients. CONCLUSIONS: Asymmetric rotation reveals disruption of self-motion perception in MD patients during the post-ictal interval, even in the absence of ocular reflex impairment. Motion misperception may cause persistent vestibular discomfort in these patients.

Persistent postural perceptual dizziness following paroxysmal positional vertigo in migraine.

OBJECTIVE: This prospective study aimed to investigate the role of migraine in favouring the onset of persistent postural perceptual dizziness (PPPD) following paroxysmal positional vertigo (PPV). METHODS: A group of patients who came to our attention suffering of PPV with or without migraine and/or vestibular migraine (VM) was examined. Three months after the resolution, an anamnestic research was conducted aimed at establishing whether any patient-related dizziness could meet the diagnostic criteria for PPPD. RESULTS: 12 of the 240 patients recruited met the diagnostic criteria for PPPD for an overall incidence of 5%, with 3 (1.85%) belonging to the non-migraine group and 9 (11.5%) to the migraine group. In the latter, 6 (28.6%) patients with VM and 3 (5.26%) without VM were affected. CONCLUSIONS: The study shows a significant increase of PPPD diagnosis in migraine compared to patients without migraine (p = 0.003). Within migraine there was a significant increase in those with VM compared to patients without VM (p = 0.0016). No difference emerged between patients without migraine and migraine patients without VM (p > 0.05). The presence of VM in patient's history, but not migraine without VM, appears to significantly increase the incidence of PPPD in patients with PPV.

Pseudo-spontaneous nystagmus increases Bow and Lean Test accuracy.

OBJECT: The aim of this study was to evaluate the effectiveness of the Bow and Lean Test (BLT) based on nystagmus intensity and direction evaluation (NID-BLT) in the diagnosis of benign paroxysmal positional vertigo of the lateral semicircular canal (LSC-BPPV). We hypothesised that the presence of a pseudo-spontaneous nystagmus increases the diagnostic accuracy of the test. METHODS: The BLT was performed in 32 subjects affected by LSC-BPPV. RESULTS: BLT was positive in 27 cases with a sensitivity of 84.3% and an accuracy of 70.4%. In other words, it was possible to carry out a BPPV root canal diagnosis (LSC) with BLT in 27 patients, of whom 19 also received a diagnosis of side and form. Pseudo-spontaneous nystagmus was detected in 15 patients, all of whom were BLT positive. In these patients, a clear diagnosis of form and side was also obtained in 14 cases (accuracy 93.3%). In the 12 patients without pseudo-spontaneous nystagmus and BLT positive, a diagnosis of side and form was reached in 5 cases (accuracy 41.6%). The comparison between percentages (Chi square test) showed a significant difference (p = 0.038). CONCLUSIONS: The presence of a pseudo-spontaneous nystagmus, as an expression of more mobile debris within the canal or a more deflectable cupula, increases the accuracy of the BLT.

Efficacy of Epley's canalith repositioning procedure according to the number of repetitions in the same session: comparison of three protocols.

BACKGROUND: The canalith repositioning manoeuvre (CRM) described by Epley remains a grade A recommended treatment for Benign Paroxysmal Positional Vertigo (BPPV) of the posterior semicircular canal (PSC). However, significant variability in the efficacy of Epley CRM has been reported. AIMS: To compare the treatment efficacy of different combinations of the Epley CRM and Dix-Hallpike retest. MATERIAL AND METHODS: Patients with PSC BPPV were divided into one of the following three treatment groups. Manoeuvre group (M): patients underwent a single Epley CRM without subsequent Dix-Hallpike retesting. Manoeuvre-Control group (MC): patients underwent up to three Epley CRM followed by Dix-Hallpike retesting until nystagmus resolution. Manoeuvre-Control-Manoeuvre group (MCM): A similar procedure to that used in the MC group except that, after the negative Dix-Hallpike retest, there was an additional CRM. RESULTS: A more favourable tendency for recovery was observed in the MCM group. There was a positive odds ratio of 1.1 between groups M and MC at the first control, 2.7 between groups M and MCM, and 2.5 between groups MC and MCM. CONCLUSIONS AND SIGNIFICANCE: Close repetition of a single Epley CRM after the first effective one would allow a positional retest to be combined with a reduction in the risk of persistent/recurrent BPPV.

Auditory perception is influenced by the orientation of the trunk relative to a sound source.

The study investigated how hearing depends on the whole body, head and trunk orientation relative to a sound source. In normal hearing humans we examined auditory thresholds and their ability to recognize logatomes (bi-syllabic non-sense words) at different whole body, head and trunk rotation relative to a sound source. We found that auditory threshold was increased and logatome recognition was impaired when the body or the trunk were rotated 40° away from a sound source compared to when the body or the trunk was oriented towards the sound source. Conversely, no effects were seen when only the head was rotated. Further, an increase of thresholds and impairment of logatome recognition were also observed after unilateral vibration of dorsal neck muscles that induces, per se, long-lasting illusory trunk displacement relative to the head. Thus, our findings support the idea that processing of acoustic signals depends on where a sound is located within a reference system defined by the subject's trunk coordinates.