Sensitivity and specificity of vestibular bed-side examination in detecting VIII cranial nerve schwannoma with sensorineural sudden unilateral hearing loss as presenting symptom.

The objectives of this study were to identify signs of vestibular nerve suffering through a bedside vestibular examination protocol in case of sudden sensorineural unilateral hearing loss without spontaneous signs of vestibular impairment and to propose a bed-side vestibular examination based protocol for the focused execution of gadolinium-enhanced magnetic resonance imaging (MRI) only if a vestibular schwannoma is suspected. 96 patients, 52 men, 44 women, mean age 57.73 +/- 12.85 years, suffering from sudden sensorineural unilateral hearing loss, which presented neither vertigo nor spontaneous nystagmus, were enrolled. Pure tone audiometry, tympanometry, measurement of acoustic reflexes and Anderson test to detect adaptation, bedside vestibular examination through head shaking test, vibration test, head impulse test, hyperventilation test and detection of nystagmus in supine and lateral decubitus to search for signs of vestibular impairment were performed. Patients with signs of vestibular impairment and pure tone audiometry threshold at high frequencies better than 70 dB nHL were subjected to auditory brainstem responses. Gadolinium enhanced MRI centred on internal acoustic canals was carried out in all patients with sudden sensorineural unilateral hearing loss. Main outcome measures were signs of vestibular impairment at vestibular bedside examination and presence of vestibular schwannoma on MRI. Signs of vestibular impairment were detected in 22/96 cases (22.9%); a vestibular schwannoma was detected by MRI in 5/96 cases (5.2%), always when vestibular impairment was present. In case of sudden sensorineural unilateral hearing loss, vestibular bedside examination seems to be useful to restrict the suspicion of a vestibular schwannoma to cases with signs of vestibular impairment, reducing the number of MRI exams, with considerable economic savings.

Anterior canal BPPV and apogeotropic posterior canal BPPV: two rare forms of vertical canalolithiasis.

Posterior canal benign paroxysmal positional vertigo (BPPV) is the most frequent form of BPPV. It is characterized by a paroxysmal positioning nystagmus evoked through Dix-Hallpike and Semont positioning tests. Anterior canal BPPV (AC) is more rare than posterior canal BPPV; it presents a prevalent down beating positioning nystagmus, with a torsional component clockwise for the left canal, counterclockwise for the right canal. Due to the possible lack of the torsional component, it is sometimes difficult to identify the affected ear. An apogeotropic variant of posterior BPPV (APC) has recently been described, characterised by a paroxysmal positional nystagmus in the opposite direction to the one evoked in posterior canal BPPV: the linear component is down-beating, the torsional component is clockwise for the right canal, counter-clockwise for the left canal, so that a contra-lateral anterior canal BPPV could be simulated. During a 16 month period, of 934 BPPV patients observed, the authors identified 23 (2.5%) cases of apogeotropic posterior canal BPPV and 11 (1.2%) cases of anterior canal BPPV, diagnosed using the specific oculomotor patterns described in the literature. Anterior canal BPPV was treated with the repositioning manoeuvre proposed by Yacovino, which does not require identification of the affected side, whereas apogeotropic posterior canal BPPV was treated with the Quick Liberatory Rotation manoeuvre for the typical posterior canal BPPV, since in the Dix-Hallpike position otoliths are in the same position if they come either from the ampullary arm or from the non-ampullary arm. The direct resolution of BPPV (one step therapy) was obtained in 12/34 patients, 8/23 patients with APC and 4/11 patients with AC; canalar conversion into typical posterior canal BPPV, later treated through Quick Liberatory Rotation (two-step therapy), was obtained in 19 patients,14/23 with APC and 5/11 with AC. Three patients were lost to follow-up. Considering the effects of therapeutic manoeuvres, the authors propose a grading system for diagnosis of AC and APC: "certain" when a canalar conversion in ipsilateral typical posterior canal BPPV is obtained; "probable" when APC or AC are directly resolved; "possible" when disease is not resolved and cerebral neuroimaging is negative for neurological diseases. Our results show that the oculomotor patterns proposed in the literature are effective in diagnosing APC and AC, and that APC is more frequent than AC. Both of these rare forms of vertical canal BPPV can be treated effectively with liberatory manoeuvres.

Direction-fixed paroxysmal nystagmus lateral canal benign paroxysmal positioning vertigo (BPPV): another form of lateral canalolithiasis.

Benign paroxysmal positioning vertigo (BPPV) is the most frequent vertiginous syndrome. It is caused either by free-floating otoliths in the semicircular canals (canalolithiasis) or by otoconial debris adhering to a canal cupula (cupulolithiasis). The posterior canal is the most frequently involved (80%), while the lateral canal is involved less frequently (15%), and the rarest conditions are anterior canalolithiasis and apogeotropic posterior canalolithiasis (5%). The main diagnostic sign of lateral canal BPPV is paroxysmal horizontal bidirectional positioning nystagmus evoked through Pagnini-McClure's test (head roll in the yaw plane in supine position). In the geotropic variant, which is more frequent, the fast phase of the nystagmus is directed towards the lowermost ear, when the patient lies on the affected side or on the healthy side; in the apogeotropic variant, which is less frequent, the fast phase is directed always toward the uppermost ear, regardless of which side the patient lies on. Paroxysmal nystagmus is more intense on the affected side in the geotropic form, and more intense on the healthy side in the apogeotropic form. The authors describe five cases of another primitive and rare form of lateral BPPV, defined as "direction-fixed paroxysmal nystagmus lateral canal BPPV", which has previously been described by other authors as a transitory step observed during the transformation from an apogeotropic into a geotropic form. It is characterized by typical BPPV symptoms and diagnosed by the presence of a paroxysmal horizontal unidirectional positioning nystagmus, evoked through Pagnini-McClure's test, which is apogeotropic on the affected side and geotropic on the healthy side. In the reported cases, direction-fixed horizontal paroxysmal nystagmus was always transformed into a typical geotropic form. The clinical features and pathophysiology of direction-fixed nystagmus lateral canal BPPV are discussed.

Hyperventilation-induced nystagmus in a large series of vestibular patients.

The Hyperventilation Test is widely used in the "bed-side examination" of vestibular patients. It can either activate a latent nystagmus in central or peripheral vestibular diseases or it can interact with a spontaneous nystagmus, by reducing it or increasing it. Aims of this study were to determine the incidence, patterns and temporal characteristics of Hyperventilation-induced nystagmus in patients suffering from vestibular diseases, as well as its contribution to the differential diagnosis between vestibular neuritis and neuroma of the 8(th) cranial nerve, and its behaviour in some central vestibular diseases. The present study includes 1202 patients featuring, at vestibular examination, at least one sign of vestibular system disorders or patients diagnosed with a "Migraine-related vertigo" or "Chronic subjective dizziness". The overall incidence of Hyperventilation-induced nystagmus was 21.9%. It was detected more frequently in retrocochlear vestibular diseases rather than in end-organ vestibular diseases: 5.3% in Paroxysmal Positional Vertigo, 37.1% in Menière's disease, 37.6% in compensated vestibular neuritis, 77.2% in acute vestibular neuritis and 91.7% in neuroma of the 8(th) cranial nerve. In acute vestibular neuritis, three HVIN patterns were observed: Paretic pattern: temporary enhancement of the spontaneous nystagmus; Excitatory pattern: temporary inhibition of the spontaneous nystagmus; Strong excitatory pattern: temporary inversion of the spontaneous nystagmus. Excitatory patterns proved to be time-dependent in that they disappeared and were replaced by the paretic pattern over a period of maximum 18 days since the beginning of the disorder. In acoustic neuroma, Hyperventilation-induced nystagmus was frequently observed (91.7%), either in the form of an excitatory pattern (fast phases towards the affected site) or in the form of a paretic pattern (fast phases towards the healthy side). The direction of the nystagmus is only partially related to tumour size, whereas other mechanisms, such as demyelination or a break in nerve fibres, might have an important role in triggering the situation. Hyperventilation-induced nystagmus has frequently been detected in cases of demyelinating diseases and in cerebellar diseases: in multiple sclerosis, hyperventilation inhibits a central type of spontaneous nystagmus or evokes nystagmus in 75% of patients; in cerebellar diseases, hyperventilation evokes or enhances a central spontaneous nystagmus in 72.7% of patients. In conclusion the Hyperventilation Test can provide patterns of oculomotor responses that indicate a diagnostic investigation through cerebral magnetic resonance imaging enhanced by gadolinium, upon suspicion of neuroma of the 8(th) cranial nerve or of a central disease. In our opinion, however, Hyperventilation-induced nystagmus always needs to be viewed within the more general context of a complete examination of the vestibular and acoustic system.

"Secondary signs of lateralization" in apogeotropic lateral canalolithiasis.

The diagnosis of lateral canalolithiasis is based on the typical finding of the horizontal paroxysmal positional nystagmus induced by the Pagnini-Mc Clure manoeuvre. This technique usually identifies also the affected side, namely, the side where the paroxysmal nystagmus is more intense in geotropic forms and the side where the paroxysmal nystagmus is less intense in apogeotropic forms. However, this method is not always applicable since, especially in apogeotropic forms, the intensity of the nystagmus is not so distinctly different between the two sides. Further useful signs to identify the affected side have been described in the Literature: Pseudo-spontaneous nystagmus in the sitting position; Leaning and Bowing nystagmus; Null-point in the vertical plane; Sitting to supine positioning nystagmus; Null-point in the horizontal plane. They are fully explained at pathophysiological level by the mechanism of canalolithiasis, as they are caused by otoliths moving in the ampullopetal direction in the non-ampullary segment (geotropic canalolithiasis) of the lateral canal or in ampullofugal direction in the ampullary segment (apogeotropic canalolithiasis) of the lateral canal. In other words, the movement of otoliths determines excitatory or inhibitory endolymphatic flow that generates specific nystagmic eye-movements. Authors analyse the characteristics of these signs, that they define as "Secondary signs of lateralization", in 64 cases of apogeotropic lateral canalolithiasis. A decisive contribution of the "Secondary signs of lateralization" to diagnose the pathological side has been verified in 13 out of 64 cases, whereas, in all other cases, Pagnini-Mc Clure diagnostic manoeuvre proved successful in correctly identifying the affected side by itself. Among the "Secondary signs of lateralization", the Pseudo-spontaneous nystagmus in the sitting position and the Sitting to the supine positioning nystagmus were particularly useful, due to both their frequency and their easy detection, as they do not require additional manoeuvres besides those usually performed during health examination of a patient affected by lateral canalolithiasis. In conclusion, the Authors propose a decision-making algorithm to diagnose and treat lateral canalolithiasis based on the attempt to obtain as much information as possible for a correct diagnosis, with the least trouble and inconvenience for patients.

Converting apogeotropic into geotropic lateral canalolithiasis by head-pitching manoeuvre in the sitting position.

Liberatory treatment of lateral canalolithiasis is more effective for the geotropic, than for the apogeotropic forms and, therefore, it is worthwhile attempting to convert the apogeotropic forms into the geotropic forms. In 36 cases of apogeotropic lateral canalolithiasis, one to five Head-Pitch Manoeuvres were performed in the sitting position (Head-Pitch Test) in the attempt to transform apogeotropic into geotropic lateral canalolithiasis. The Head Pitch Test was performed by a quick 60 degrees forward-flexion and a slow maximal backward-extension of the head. The Head-Pitch Test was effective in 36.1% of cases, less than the repeated Head-Rolling in the supine position, but it was always well tolerated by patients. The quick 60 degrees forward-flexion of the head can evoke a horizontal nystagmus beating towards the healthy side in apogeotropic lateral canalolithiasis and towards the affected side in geotropic lateral canalolithiasis (Bow Nystagmus). Slow backward-extension of the head can evoke a horizontal nystagmus beating towards the affected side in apogeotropic lateral canalolithiasis and toward the healthy side in geotropic lateral canalolithiasis (Lean Nystagmus). Conversion from apogeotropic to geotropic lateral canalolithiasis by the Head-Pitch Test was effective when Bow and Lean Nystagmus changed directions or when the Head-Pitch Test evoked Bow Nystagmus toward the affected side and Lean Nystagmus toward the healthy side. Conversion occurred in 10 patients during the 60 degrees forward-flexion of the head. In contrast, in 3 patients, it occurred during extension of the head, when a "Lean Nystagmus" toward the healthy side appeared. In addition, Pseudospontaneous Nystagmus and Positioning Nystagmus that arose when the patient moved from the sitting to the supine position changed direction or were evoked ex-novo, both directed toward the healthy side. In all cases, Pagnini-McClure diagnostic manoeuvre confirmed the transformation with a Positional Paroxysmal Horizontal Geotropic Nystagmus, which was more intense when the affected ear was brought down. The Head-Pitch Test can be used as the method of choice to transform apogeotropic into geotropic lateral canalolithiasis. However, anterior flexion of the head in the geotropic forms must be avoided since involuntary and harmful transformations from the geotropic into the apogeotropic form can occur, moving otoliths towards the anterior arm and cupula.

Treatment of benign paroxysmal positional vertigo of posterior semicircular canal by "Quick Liberatory Rotation Manoeuvre".

Treatment of Benign Paroxysmal Positional Vertigo is based on Semont's Liberatory Manoeuvre and on so-called "Canalith Repositioning Manoeuvres", derived from the original Epley technique. Both manoeuvres are very effective and choice of which to use depends on the experience of the physician. Semont's manoeuvre requires a quick movement of the patient in mass in the frontal plane, from the involved, to the contralateral side, which sometimes causes symptoms such as nausea or vomiting. In this technique, a secondary liberatory nystagmus is often observed as sign of the success of the manoeuvre. Repositioning manoeuvres are less fastidious because of the slow movements, but we rarely observe an objective sign of success like the liberatory nystagmus. In the present randomised trial, 300 patients with posterior canalo/cupulolithias were divided into 3 treatment groups: 100 treated by Semont Technique; 100 by a Repositioning procedure (Parnes technique); 100 by a new manoeuvre called "Quick Liberatory Rotation". Results of treatment are also compared with the natural evolution of Benign Paroxysmal Positional Vertigo observed in 18 untreated patients. Quick Liberatory Rotation is similar in the sequence of the positions of the head in the horizontal plane, to repositioning procedures, but is more like the Semont manoeuvre in the speed of the movement (about 180 degrees in less than one second). Quick Liberatory Rotation is easy to perform, well tolerated and very effective (success rate: 98% in one-three cycles). In the present investigation, a secondary liberatory nystagmus was observed in 76.1%, with a sensitivity of 81.9% in detecting patients who had completely recovered and a specificity of 43.8% in detecting failures. Effectiveness, in short and medium period (1-15 months), is similar to Semont and Parnes techniques. Authors consider Quick Liberatory Rotation, at present, a possible first choice technique in the treatment of posterior canalolithiasis.

[Sign-report: torsional nystagmus from head-shaking in patients with labyrinth lithiasis of the vertical canal]. / Sign-report: nistagmo torsionale da head-shaking test in pazienti con labirintolitiasi dei canali verticali.

The clinical picture of Positional Paroxysmal Vertigo (PPV) induced by vertical canal labyrintholithiasis has been clearly described, eliminating previous interpretations of pathogenesis of this disorder. The diagnosis of PPV is based on the well-known picture of positional paroxysmal Nystagmus. The Authors report a clinical sign which has not previously been reported in the literature: torsional Nystagmus induced by the Head-Shaking Test (HST). The Authors encoutered this sign in 30% of the cases of vertical canalolithiasis and in 50% of the cases diagnosed as vertical cupulolithiasis. This sign was also found in patients with a history of prior positional vertigo and in patients who, after treatment with release maneuver, no longer show clinical signs of positional vertigo. Such Nystagmus was not, however, found in the control group (normal subjects and patients suffering from other vestibular pathologies). In the present study the possible pathogenesis of this sign is discussed and some practical implications are considered.