Perceptual precision of passive body tilt is consistent with statistically optimal cue integration.

When making perceptual decisions, humans have been shown to optimally integrate independent noisy multisensory information, matching maximum-likelihood (ML) limits. Such ML estimators provide a theoretic limit to perceptual precision (i.e., minimal thresholds). However, how the brain combines two interacting (i.e., not independent) sensory cues remains an open question. To study the precision achieved when combining interacting sensory signals, we measured perceptual roll tilt and roll rotation thresholds between 0 and 5 Hz in six normal human subjects. Primary results show that roll tilt thresholds between 0.2 and 0.5 Hz were significantly lower than predicted by a ML estimator that includes only vestibular contributions that do not interact. In this paper, we show how other cues (e.g., somatosensation) and an internal representation of sensory and body dynamics might independently contribute to the observed performance enhancement. In short, a Kalman filter was combined with an ML estimator to match human performance, whereas the potential contribution of nonvestibular cues was assessed using published bilateral loss patient data. Our results show that a Kalman filter model including previously proven canal-otolith interactions alone (without nonvestibular cues) can explain the observed performance enhancements as can a model that includes nonvestibular contributions.NEW & NOTEWORTHY We found that human whole body self-motion direction-recognition thresholds measured during dynamic roll tilts were significantly lower than those predicted by a conventional maximum-likelihood weighting of the roll angular velocity and quasistatic roll tilt cues. Here, we show that two models can each match this "apparent" better-than-optimal performance: 1) inclusion of a somatosensory contribution and 2) inclusion of a dynamic sensory interaction between canal and otolith cues via a Kalman filter model.

Delayed onset of rotatory self-motion perception, dysdiadochokinesia and disturbed eye pursuit caused by low-dose pregabalin.

A 30-year-old woman with chronic foot pain after an orthopaedic surgery and chronic neck pain presented to the emergency department (ED) with a history of self-rotatory vertigo with unsteadiness. She had started low-dose pregabalin, 25 mg two times a day 9 months before experiencing symptoms with the dose gradually increased to 150 mg two times a day over this period. Clinical examination revealed difficulty performing eye pursuit with left eye and dysdiadochokinesia of the left arm. Owing to a suspicion of multiple sclerosis she underwent cerebral MRI, which was normal. Pregabalin was tapered over 2 months with a complete disappearance of the symptoms. We concluded that symptoms were due to pregabalin treatment.

Flash induced afterimage versus single spot visual object influence on visual-vestibular interaction in detection threshold for self-motion perception.

In seven healthy subjects we studied the effect of flash induced afterimage on perceptual threshold for self-motion during sinusoidal vertical axis rotation compared to rotation in darkness, and rotation with subject's gaze fixed on a 'real' visual object rotated with him. For a real object we used light-emitting diode (LED) aligned with subject's head. A MOOG motion platform was used to generate motion. Single cycles of sinusoidal acceleration at four frequencies: 0.1, 0.2, 0.5, and 1Hz were used as motion stimuli. The results show that the threshold when subjects stare at an afterimage during rotation is consistently lower compared to rotation in darkness. However, compared to the threshold during rotation with a 'real' object visual fixation it is higher, significantly at frequencies 0.5 and 0.2Hz (p<0.05). The threshold is frequency dependent - it decreases with increase of the frequency (p<0.01). The probable mechanism of afterimage influence on perceptual threshold for self-motion is discussed.

Adaptation of vestibular tone studied with electrical stimulation of semicircular canal afferents.

Damage to one vestibular labyrinth or nerve causes a central tone imbalance, reflected by prominent spontaneous nystagmus. Central adaptive mechanisms eliminate the nystagmus over several days, and the mechanisms underlying this process have received extensive study. The characteristics of vestibular compensation when the tone imbalance is presented gradually or repeatedly have never been studied. We used high-frequency electrical stimulation of semicircular canal afferents to generate a vestibular tone imbalance and recorded the nystagmus produced when the stimulation was started abruptly or gradually and when it was repeatedly cycled on and off. In the acute-onset protocol, brisk nystagmus occurred when stimulation started, gradually resolved within 1 day, and reversed direction when the stimulation was stopped after 1 week. Repeated stimulation cycles resulted in progressively smaller nystagmus responses. In the slow-onset protocol, minimal nystagmus occurred while the stimulation ramped-up to its maximum rate over 12 h, but a reversal still occurred when the stimulation was stopped after 1 week, and repeated stimulation cycles did not affect this pattern. The absence of nystagmus during the 12 h ramp of stimulation demonstrates that central vestibular tone can rebalance relatively quickly, and the reduction in the stimulation-off nystagmus with repeated cycles of the acute-onset but not the slow-onset stimulation suggests that dual-state adaptation may have occurred with the former paradigm but not the latter.

Dynamic tilt thresholds are reduced in vestibular migraine.

Vestibular symptoms caused by migraine, referred to as vestibular migraine, are a frequently diagnosed but poorly understood entity. Based on recent evidence that normal subjects generate vestibular-mediated percepts of head motion and reflexive eye movements using different mechanisms, we hypothesized that percepts of head motion may be abnormal in vestibular migraine. We therefore measured motion detection thresholds in patients with vestibular migraine, migraine patients with no history of vestibular symptoms, and normal subjects using the following paradigms: roll rotation while supine (dynamically activating the semicircular canals); quasi-static roll tilt (statically activating the otolith organs); and dynamic roll tilt (dynamically activating the canals and otoliths). Thresholds were determined while patients were asymptomatic using a staircase paradigm, whereby the peak acceleration of the motion was decreased or increased based on correct or incorrect reports of movement direction. We found a dramatic reduction in motion thresholds in vestibular migraine compared to normal and migraine subjects in the dynamic roll tilt paradigm, but normal thresholds in the roll rotation and quasi-static roll tilt paradigms. These results suggest that patients with vestibular migraine may have enhanced perceptual sensitivity (e.g. increased signal-to-noise ratio) for head motions that dynamically modulate canal and otolith inputs together.

Management of congenital third branchial arch anomalies: a systematic review.

OBJECTIVE: To systematically review the existing literature on third branchial arch anomalies and suggest guidelines for their management. DATA SOURCES: We searched PubMed, Medline, and Embase using Scopus, and collected additional publications cited in bibliographies. We included all English-language articles and all foreign-language articles with an English abstract. REVIEW METHODS: Two investigators reviewed all cases explicitly identified as third arch anomalies or meeting anatomical criteria for third arch anomalies; they assessed presentation, diagnostic methods, intervention, and outcome. RESULTS: We found 202 cases of third arch anomalies; they presented primarily on the left side (89%), usually as neck abscess (39%) or acute suppurative thyroiditis (33%). Barium swallow, direct laryngoscopy, and magnetic resonance imaging were the most useful diagnostic tools. The recurrence rate varied among the treatment options: incision and drainage, 94 percent; endoscopic cauterization of the sinus tract opening, 18 percent; open-neck surgery and tract excision, 15 percent; and partial thyroidectomy during open-neck surgery, 14 percent. Complications after surgery appeared somewhat more frequently in children eight years of age or younger. CONCLUSION: Third arch anomalies are more common than previously reported. They appear to be best treated by complete excision of the cyst, sinus, or fistula during a quiescent period. Repeated incision and drainage yields high rates of recurrence and should be avoided. Complications might be minimized by first initiating antibiotic treatment, delaying surgical treatment until the inflammatory process is maximally resolved, and by using endoscopic cauterization.

Management of congenital fourth branchial arch anomalies: a review and analysis of published cases.

BACKGROUND/PURPOSE: Congenital fourth branchial arch anomalies are uncommon entities, heretofore described only in case reports, affecting primarily children, and typically presenting as a cervical inflammatory process. The aim of the study was to collect appropriate data on the diagnosis, treatment, and outcome of this condition and to suggest guidelines for its management. METHODS: We conducted a structured review of the literature for cases explicitly identified as congenital fourth branchial arch anomalies or meeting anatomical criteria for this condition. We computed descriptive statistics and performed several post hoc 2-way comparisons of subgroups of cases. RESULTS: We located and critically evaluated 526 cases. Fourth arch anomalies were usually located on the left (94%) and generally presented as acute suppurative thyroiditis (45%) or recurrent neck abscess (42%). Barium swallow and direct laryngoscopy were the most useful diagnostic tools. Treatment options differed mainly in recurrence rates: incision and drainage, 89%; open neck surgery and tract excision, 15%; endoscopic cauterization of the sinus tract opening, 15%; and open neck surgery with partial thyroidectomy, 8%. Complications after surgery occurred primarily in children 8 years or younger. CONCLUSION: Fourth arch anomalies are more common than once thought. Treatment of these disorders with repeated incision and drainage yields high rates of recurrence; thus, complete excision of the entire fistula tract during a quiescent period appears preferable. Combining this surgery with partial thyroidectomy may further decrease recurrence rates. Complications can likely be minimized by using antibiotic treatment of acute infections or endoscopic cauterization in children 8 years or younger, and delaying open neck surgery.

Extreme sensitivity of hearing to decreases of ICP in Menière's disease.

We report the case of a Menière's disease patient affected by normal pressure hydrocephalus (NPH) who presented a cerebrospinal fluid (CSF) pressure-dependent hearing impairment after shunting. This side-effect was not only reversible and reproducible but occurred at a high opening pressure when the valve setting was lowered by only 0.7 mmHg (10 mmH(2)O). This observation suggests that hearing in Menière's disease might be very sensitive to small reductions of intracranial pressure (ICP) and that these patients should be informed of this potential risk, which can compromise the efficacy of the shunt.

Vestibular thresholds for yaw rotation about an earth-vertical axis as a function of frequency.

Perceptual direction detection thresholds for yaw rotation about an earth-vertical axis were measured at seven frequencies (0.05, 0.1, 0.2, 0.5, 1, 2, and 5 Hz) in seven subjects in the dark. Motion stimuli consisted of single cycles of sinusoidal acceleration and were generated by a motion platform. An adaptive two-alternative categorical forced-choice procedure was used. The subjects had to indicate by button presses whether they perceived yaw rotation to the left or to the right. Thresholds were measured using a 3-down, 1-up staircase paradigm. Mean yaw rotation velocity thresholds were 2.8 deg s(-1) for 0.05 Hz, 2.5 deg s(-1) for 0.1 Hz, 1.7 deg s(-1) for 0.2 Hz, 0.7 deg s(-1) for 0.5 Hz, 0.6 deg s(-1) for 1 Hz, 0.4 deg s(-1) for 2 Hz, and 0.6 deg s(-1) for 5 Hz. The results show that motion thresholds increase at 0.2 Hz and below and plateau at 0.5 Hz and above. Increasing velocity thresholds at lower frequencies qualitatively mimic the high-pass characteristics of the semicircular canals, since the increase at 0.2 Hz and below would be consistent with decreased gain/sensitivity observed in the VOR at lower frequencies. In fact, the measured dynamics are consistent with a high pass filter having a threshold plateau of 0.71 deg s(-1) and a cut-off frequency of 0.23 Hz, which corresponds to a time constant of approximately 0.70 s. These findings provide no evidence for an influence of velocity storage on perceptual yaw rotation thresholds.

Cervical chordoma with retropharyngeal extension presenting with impaired voice.

AIMS AND BACKGROUND: We report an extremely rare case of cervical chordoma presenting with impaired voice. METHOD: Case report and a review of the literature concerning the presentation, diagnosis, and treatment of a cervical chordoma. RESULTS: A singing teacher complaining of dysphonia was examined and surgically treated for a retropharyngeal extension of a cervical chordoma. A local recurrence was treated with proton beam therapy. Among primary malignant tumors of bone, chordomas account for 3-4% of all cases. Chordoma is typically a locally aggressive tumor with a high propensity for local recurrence. Its management involves surgery, radiotherapy, or both. CONCLUSION: To our knowledge this is the first report in the world literature of a retropharyngeal extension of a cervical chordoma presenting with impaired voice. This case indicates that bony tumors of the spine may present first to voice-disorder clinicians. Increased awareness of this neoplasm may lead to earlier diagnosis and better treatment.

Surgery for large vestibular schwannomas: how patients and surgeons perceive quality of life.

OBJECT: The aim of this study was to assess the consequences of total removal of a large vestibular schwannoma on the patient's symptoms and quality of life (QOL). METHODS: A questionnaire regarding preoperative and postoperative symptoms with measures of both daily and global QOL and a modified 36-Item Short Form Health Survey (SF-36) QOL instrument were sent to 103 patients who had undergone surgery via a retrosigmoid approach for total removal of a Grade III or IV vestibular schwannoma. In addition, 48 patients underwent follow-up clinical examinations to assess their conditions. Seventy-two of the 103 patients completed and returned the questionnaire. Forty-six (64%) of the schwannomas were Grade IV and 26 (36%) were Grade III. The patients' pre- and postoperative symptoms were similar to those reported in other studies. The patients' perceptions of facial movement were likely to be worse than the clinicians' estimation based on the House-Brackmann classification. All scores in the QOL categories were significantly reduced when compared with normative data. Patients with large vestibular schwannomas had lower scores in all SF-36 categories except pain compared with data from other studies. Psychological problems were the preponderant symptoms, and their presence was the most powerful predictive variable for global and daily QOL. CONCLUSIONS: Surgery for a large vestibular schwannoma has a significant impact on the patient's QOL. To improve QOL postoperatively, the patient should be prepared and well informed of the consequences of such a surgery on QOL. Clinicians must be aware that early involvement of a clinical psychologist may be very helpful.

Intralabyrinthine haemorrhage following cocaine consumption.

The origin of cochleovestibular deficits remains hypothetical, a viral attack or a circulatory disorder being the two most frequently reported hypotheses. We report the case history of a patient suffering from a cochleovestibular deficit after consumption of cocaine, a drug known for its vascular effects. The MRI scans were compatible with an intralabyrinthine haemorrhage. To our knowledge, this is the first case of cochleovestibular deficit due to an intralabyrinthine haemorrhage following cocaine consumption.