Abstract of the Week
No. 106: January 18, 2012
Psillas G, Triaridis S, Markou K, Tsalighopoulos M, Vital V. Benign paroxysmal positional vertigo in the first acute attack of Ménière's disease. B-ENT. 2011;7(2):131-5.
A 69-year-old woman, with no history of vertigo attacks, presented with the classical triad of symptoms for Ménière's disease in the right ear (vertigo, tinnitus, fullness). Upon admission, the patient had a third-degree horizontal nystagmus beating to the right, after beating towards the left ear a few hours earlier. Audiometry confirmed a severe sensorineural hearing loss in the right ear, especially at low and high frequencies. The following day, the patient complained of short episodes of vertigo linked to head movement, and the Hallpike test was compatible with benign paroxysmal positional vertigo (BPPV) in the right ear. To our knowledge this is the first description of BPPV of the posterior semicircular canal manifesting during the first vertiginous attack of Ménière's disease in the same ear. It was possible that the hydropic distension or rupture damaged the otolithic apparatus, leading to the release of otoconia debris which migrated to the posterior semicircular canal where it resulted in BPPV.
No. 105: January 11, 2012
Fiorino F, Pizzini FB, Beltramello A, Barbieri F. Progression of endolymphatic hydrops in Ménière's disease as evaluated by magnetic resonance imaging. Otol Neurotol. 2011 Sep;32(7):1152-7.
OBJECTIVE: To evauate the presence and the degree of endolymphatic hydrops (EHs) in patients with unilateral Ménière's disease (MD), as a function of duration of the disease, estimated using a 3-dimensional fluid-attenuated inversion recovery sequence in a 3-Tesla magnetic resonance imaging unit, after intratympanic gadolinium administration. PATIENTS: A total of 32 patients (21 male and 11 female subjects, aged 25-78 yr; median, 56 yr) participated in the investigation. The duration of the disease ranged from 2 months to 10 years (median, 3 yr), with a prevalence of vertigo spells in the last 6 months ranging from 0.5 to 8 per month (median, 2.5). INTERVENTION: A 0.6-ml solution of gadobutrol (1 mmol/ml) diluted 1:7 in saline was injected in the affected ear through the inferior-posterior quadrant of the tympanic membrane, using a 22-gauge spinal needle. The patient was kept with the head rotated 45 degrees contralaterally for 30 minutes after each injection. Twenty-four hours later, a 3-dimensional fluid-attenuated inversion recovery magnetic resonance imaging was performed. MAIN OUTCOME MEASURE: Perilymphatic enhancement was evaluated in different portions of the labyrinth as a function of MD duration. RESULTS: Reduced or absence of enhancement of the vestibule occurred precociously and occurred in all subjects at long term. The prevalence of enhancement abnormalities in the cochlea and the semicircular canals was directly proportional to MD duration. At long term, the vestibule and the cochlea showed a more severe hydropic involvement compared with semicircular canals. A statistical significant correlation between enhancement abnormalities and MD duration was observed for most inner ear sites. CONCLUSION: The increased prevalence and severity of EH with the duration of MD indicates that hydrops is a progressive degenerative phenomenon. The frequent abnormality in the vestibule and, secondarily, in the cochlea is in line with some histopathologic investigations. It remains to be clarified whether hydropic changes are related to specific signs and symptoms of MD.
No. 104: January 4, 2012 (Happy New Year!)
Schuknecht HF, Gulya AJ. Endolymphatic hydrops. An overview and classification. Ann Otol Rhinol Laryngol Suppl. 1983 Sep-Oct;106:1-20.
Endolymphatic hydrops (EH) is a pathological condition which is the final common manifestation of a variety of otologic insults. In this paper we develop a classification which, on the basis of clinical and pathological data, distinguishes symptomatic and asymptomatic forms. Clinical case histories and temporal bone studies are presented to illustrate and substantiate this classification. The symptomatic form becomes evident by the hallmark symptoms of episodic vertigo and fluctuating hearing loss. The asymptomatic form is silent. Interconversion from one form to another may occur over time. Each of the forms can be subdivided, according to etiology, into embryopathic, acquired, and idiopathic types. The embryopathic type comprises those cases in which some noxious influence interferes with prenatal labyrinthine development. The acquired type includes those cases in which a documented insult, be it inflammatory or traumatic, is suffered by a previously normal labyrinth. The inflammation may be viral, bacterial, or spirochetal in nature, while the traumatic event may be either accidentally or surgically sustained. The idiopathic type includes cases in which the instigating event precipitating the EH is unknown. Menière's disease represents merely one example of the EH group of disorders, namely symptomatic idiopathic EH.
No. 103: December 28, 2011
Grabherr L, Cuffel C, Guyot JP, Mast FW. Mental transformation abilities in patients with unilateral and bilateral vestibular loss. Exp Brain Res. 2011 Mar;209(2):205-14.
Vestibular information helps to establish a reliable gravitational frame of reference and contributes to the adequate perception of the location of one's own body in space. This information is likely to be required in spatial cognitive tasks. Indeed, previous studies suggest that the processing of vestibular information is involved in mental transformation tasks in healthy participants. In this study, we investigate whether patients with bilateral or unilateral vestibular loss show impaired ability to mentally transform images of bodies and body parts compared to a healthy, age-matched control group. An egocentric and an object-based mental transformation task were used. Moreover, spatial perception was assessed using a computerized version of the subjective visual vertical and the rod and frame test. Participants with bilateral vestibular loss showed impaired performance in mental transformation, especially in egocentric mental transformation, compared to participants with unilateral vestibular lesions and the control group. Performance of participants with unilateral vestibular lesions and the control group are comparable, and no differences were found between right- and left-sided labyrinthectomized patients. A control task showed no differences between the three groups. The findings from this study substantiate that central vestibular processes are involved in imagined spatial body transformations; but interestingly, only participants with bilateral vestibular loss are affected, whereas unilateral vestibular loss does not lead to a decline in spatial imagery.
No. 102: December 21, 2011
Peruch P, Lopez C, Redon-Zouiteni C, Escoffier G, Zeitoun A, Sanjuan M, Deveze A, Magnan J, Borel L. Vestibular information is necessary for maintaining metric properties of representational space: evidence from mental imagery. Neuropsychologia 2011 Sep;49(11):3136-44.
The vestibular system contributes to a wide range of functions, from postural and oculomotor reflexes to spatial representation and cognition. Vestibular signals are important to maintain an internal, updated representation of the body position and movement in space. However, it is not clear to what extent they are also necessary to mentally simulate movement in situations that do not involve displacements of the body, as in mental imagery. The present study assessed how vestibular loss can affect object-based mental transformations (OMTs), i.e., imagined rotations or translations of objects relative to the environment. Participants performed one task of mental rotation of 3D-objects and two mental scanning tasks dealing with the ability to build and manipulate mental images that have metric properties. Menière's disease patients were tested before unilateral vestibular neurotomy and during the recovery period (1 week and 1 month). They were compared to healthy participants tested at similar time intervals and to bilateral vestibular-defective patients tested after the recovery period. Vestibular loss impaired all mental imagery tasks. Performance varied according to the extent of vestibular loss (bilateral patients were frequently the most impaired) and according to the time elapsed after unilateral vestibular neurotomy (deficits were stronger at the early stage after neurotomy and then gradually compensated). These findings indicate that vestibular signals are necessary to perform OMTs and provide the first demonstration of the critical role of vestibular signals in processing metric properties of mental representations. They suggest that vestibular loss disorganizes brain structures commonly involved in mental imagery, and more generally in mental representation.
No. 101: December 14, 2011
Lopez C, Vibert D, Mast FW. Can imagined whole-body rotations improve vestibular compensation? Med Hypotheses. 2011 Jun;76(6):816-9. Epub 2011 Mar 12.
Unilateral damage to the labyrinth and the vestibular nerve cause rotational vertigo, postural imbalance, oculomotor disorders and spatial disorientation. Electrophysiological investigations in animals revealed that such deficits are partly due to imbalanced spontaneous activity and sensitivity to motion in neurons located in the ipsilesional and contralesional vestibular nuclei. Neurophysiological reorganizations taking place in the vestibular nuclei are the basis of the decline of the symptoms over time, a phenomenon known as vestibular compensation. Vestibular compensation is facilitated by motor activity and sensory experience, and current rehabilitation programs favor physical activity during the acute stage of a unilateral vestibular loss. Unfortunately, vestibular-defective patients tend to develop strategies in order to avoid movements causing imbalance and nausea (in particular body movements towards the lesioned side), which impedes vestibular compensation. Neuroanatomical evidence suggests a cortical control of postural and oculomotor reflexes based on corticofugal projections to the vestibular nuclei and, therefore, the possibility to manipulate vestibular functions through top-down mechanisms. Based on evidence from neuroimaging studies showing that imagined whole-body movements can activate part of the vestibular cortex, we propose that mental imagery of whole-body rotations to the lesioned and to the healthy side will help rebalancing the activity in the ipsilesional and contralesional vestibular nuclei. Whether imagined whole-body rotations can improve vestibular compensation could be tested in a randomized controlled study in such patients beneficiating, or not, from a mental imagery training. If validated, this hypothesis will help developing a method contributing to reduce postural instability and falls in vestibular-defective patients. Imagined whole-body rotations thus could provide a simple, safe, home-based and self-administered therapeutic method with the potential to overcome the inconvenience related to physical movements.
No. 100!! December 7, 2011
Rodionov V, Zislin J, Elidan J. Imagination of body rotation can induce eye movements. Acta Otolaryngol. 2004 Aug;124(6):684-9.
OBJECTIVE: Several studies have shown that spatiotemporal aspects of motion are stored and can be retrieved with the use of vestibular and somatosensory cues. The purpose of this study was to examine whether intentional imagination of body rotation can induce oculomotor activity similar to the typical vestibulo-ocular reflex (VOR). MATERIAL AND METHODS: Normal subjects without known vestibular and/or oculometric abnormalities were instructed to imagine a sensation of accelerating body rotation in the horizontal plane (rightward or leftward) while sitting in darkness with closed eyes, using only vestibular and somatosensory cues and not imaginary visual cues. Eye movements were recorded during the imagery session and also during a full, routine electronystagmography (ENG) test. All subjects selected for this study showed normal results in the ENG test, and none of them had gaze-evoked or end-point nystagmus. RESULTS: In response to imaginary rotations, horizontal eye movements were found in 91/121 recordings (75%) in 10 subjects. A typical pattern of nystagmus (0.3-3 Hz, 3-30 degrees /s maximal speed of slow component) was recorded in 53% of mental rightward rotations and 49% of leftward rotations. The fast component was always in the direction of the imaginary rotation (similar to a normal VOR). Other types of eye movement comprised either contralateral eye drift ( approximately 17% of trials) or macro square waves. In 25% of the recordings no definite eye movements could be detected during the mental maneuvers. CONCLUSION: These mentally induced eye movements seem to be due to a cortical process which can affect the normal input to the brainstem nuclei. A possible mechanism is discussed. This phenomenon may serve as an objective measurement of mental activity, may be used for testing the cognitive resources of patients and can probably be used for enhancing the rehabilitation process after acute vestibular insult.