Central presbycusis: a review and evaluation of the evidence.

BACKGROUND: The authors reviewed the evidence regarding the existence of age-related declines in central auditory processes and the consequences of any such declines for everyday communication. PURPOSE: This report summarizes the review process and presents its findings. DATA COLLECTION AND ANALYSIS: The authors reviewed 165 articles germane to central presbycusis. Of the 165 articles, 132 articles with a focus on human behavioral measures for either speech or nonspeech stimuli were selected for further analysis. RESULTS: For 76 smaller-scale studies of speech understanding in older adults reviewed, the following findings emerged: (1) the three most commonly studied behavioral measures were speech in competition, temporally distorted speech, and binaural speech perception (especially dichotic listening); (2) for speech in competition and temporally degraded speech, hearing loss proved to have a significant negative effect on performance in most of the laboratory studies; (3) significant negative effects of age, unconfounded by hearing loss, were observed in most of the studies of speech in competing speech, time-compressed speech, and binaural speech perception; and (4) the influence of cognitive processing on speech understanding has been examined much less frequently, but when included, significant positive associations with speech understanding were observed. For 36 smaller-scale studies of the perception of nonspeech stimuli by older adults reviewed, the following findings emerged: (1) the three most frequently studied behavioral measures were gap detection, temporal discrimination, and temporal-order discrimination or identification; (2) hearing loss was seldom a significant factor; and (3) negative effects of age were almost always observed. For 18 studies reviewed that made use of test batteries and medium-to-large sample sizes, the following findings emerged: (1) all studies included speech-based measures of auditory processing; (2) 4 of the 18 studies included nonspeech stimuli; (3) for the speech-based measures, monaural speech in a competing-speech background, dichotic speech, and monaural time-compressed speech were investigated most frequently; (4) the most frequently used tests were the Synthetic Sentence Identification (SSI) test with Ipsilateral Competing Message (ICM), the Dichotic Sentence Identification (DSI) test, and time-compressed speech; (5) many of these studies using speech-based measures reported significant effects of age, but most of these studies were confounded by declines in hearing, cognition, or both; (6) for nonspeech auditory-processing measures, the focus was on measures of temporal processing in all four studies; (7) effects of cognition on nonspeech measures of auditory processing have been studied less frequently, with mixed results, whereas the effects of hearing loss on performance were minimal due to judicious selection of stimuli; and (8) there is a paucity of observational studies using test batteries and longitudinal designs. CONCLUSIONS: Based on this review of the scientific literature, there is insufficient evidence to confirm the existence of central presbycusis as an isolated entity. On the other hand, recent evidence has been accumulating in support of the existence of central presbycusis as a multifactorial condition that involves age- and/or disease-related changes in the auditory system and in the brain. Moreover, there is a clear need for additional research in this area.

Vertigo and balance in children--diagnostic approach and insights from imaging.

Common causes of vertigo and dizziness in childhood are vestibular migraine and associated syndromes (benign paroxysmal vertigo), unilateral vestibular failure due to labyrinthitis, positioning vertigo, and somatoform syndromes. Although the same spectrum of diseases as in adults can be found, the frequency differs widely. Further, balance disorders not related to vestibular function, like cerebral palsy, can present with dizziness. Vestibular function can reliably be addressed at the bedside by head impulses to test vestibulo-ocular reflex function, ocular motor testing of the central vestibular system, and balance tests for vestibulo-spinal function. Vestibulo-ocular reflex function can now be quantified by recording eye and head movements with high resolution video-oculography (256 Hz) and inertial sensors. Posturographic measures using artificial neuronal networks are used to classify dysbalance. Quantitative gait analysis further helps to distinguish balance disorders caused by e.g. sensory dysfunction or supraspinal disturbances. Recently, functional neuroimaging opened a view to the brain network for the control of posture and locomotion. From frontal cortex the locomotor signal is conveyed via the basal ganglia to the centers for locomotion and postural control in the brainstem tegmentum. The cerebellum is involved in sensory integration and rhythm generation during postural demands. To summarize, most syndromes causing dizziness, vertigo and imbalance can be diagnosed based on history and clinical tests. However, new data from neurophysiology and imaging help to understand the pathophysiology and the therapeutic principles in these disorders.

Cavernous angioma of the vestibular nerve: case report and literature review.

BACKGROUND: To date, 50 cases of cavernous angioma in the CPA have been reported, and previous reports did not describe the tumor's site of origin. We describe a case of a small, extraaxial cavernous angioma of the vestibular nerve. We also propose a reclassification system for cavernous angioma of the CPA based on the tumor's site of origin. CASE DESCRIPTION: A 39-year-old female patient had recurrent deteriorating vertigo and a right hearing disturbance. Magnetic resonance imaging revealed a cavernous angioma of the right CPA. Surgery was performed through a right lateral suboccipital approach. In the present case, the mass was attached to and covered the cisternal portion of the vestibular nerve, and it contained microvessels that were fed from the vascular plexus of the vestibular nerve. The tumor was resected en bloc, and the microvessels feeding it were cauterized. CONCLUSIONS: On the basis of our review of 50 cases of cavernous angioma of the CPA, we propose that these tumors can be classified according to whether they develop from the venous plexus of the dura matter or of a cranial nerve. We also suggest that the site of origin affects the postoperative symptoms.

Magnetic resonance imaging based classification of anatomic relationship between the cochleovestibular nerve and anterior inferior cerebellar artery in patients with non-specific neuro-otologic symptoms.

In this study, we aimed to assess anatomical relationship between the anterior inferior cerebellar artery (AICA) and cochleovestibular nerve (CNV) in patients with non-specific cochleovestibular symptoms using magnetic resonance imaging (MRI). One-hundred and forty patients with non-specific neuro-otologic symptoms were assessed using cranial and temporal MRI. Classification was performed according to four different types of anatomical relationship observed between the AICA and CVN. In type 1 (point compression), the AICA compresses only a limited portion of the CVN. In type 2 (longitudinal compression), the AICA approaches the CVN as both traverse parallel to each other. In type 3 (loop compression), the vascular loop of the AICA encircles the CVN. In type 4 (indentation), the AICA compresses the CVN so as to make an indentation in the nerve. The anatomical relationship between the CVN and AICA was encountered in 19 out of 140 (13.6%) patients (20 ears). The VCC was unilateral in 18 patients (94.7%) and bilateral in one patient (5.3%). There was no other vascular structure causing VCC to the CVN except for vertebral artery that was seen in 2 out of 140 patients (1.4%). These were unilateral cases. There were tinnitus, vertigo or dizziness, hearing loss, and both hearing loss and vertigo in 5 (25%), 13 (65%), 1 (5%) and 1 (5%) ears of 20 patients, respectively. There was no relationship between the cochleovestibular symptoms and type of compression (p>0.05). Neurovascular relationship between the CVN and AICA can be imaged properly using MR and MR based classification may help reporting this relationship in a standard way. Although, MR images can show the anatomical relationship accurately, diagnosis of vascular conflict should not be based on imaging findings alone.

Neurovascular compression syndrome of the eighth cranial nerve. Can the site of compression explain the symptoms?

Considerable skepticism still exists concerning the concept of neurovascular compression (NVC) syndromes of the eighth cranial nerve (8th N). If such syndromes exist, the sites of compression of the nerve must explain the symptoms encountered. We recorded compound action potentials of the cochlear nerve (CCAPs) during neurovascular decompression (NVD) to examine the topography of the three components of the 8th N. The sites of compression of the 8th N in cases of NVC syndrome confirmed at surgery were superimposed on the topography of the CN and vestibular nerve (VN) in order to determine the relationship between the sites of compression and the symptoms. CCAPs were clearly and consistently recorded on the caudal surface of the 8th N along the midline. In patients with vertigo and tinnitus there was vascular compression of the rostroventral (VN) and caudal surface (CN) of the nerve, respectively. In patients with both vertigo and tinnitus, there was compression of both VN and CN. Our findings clearly demonstrate that the symptoms of NVC of the 8th N depend on the part of the nerve that is compressed by blood vessels, and they support the concept of NVC syndrome of the 8th N.

A proposal for introducing a modified vestibular index in neurotology. The classification of vestibular neuronitis.

The parameters for vestibular dysfunction were modified after our own studies. This index includes the degree of vertigo present, spontaneous nystagmus, dysfunction of the vestibulospinal reflexes and caloric and postrotatory side differences. The index is applicable for defining the extent of a lesion, follow-up, defining its stage and the results of therapy. Introduction of the modified vestibular index is proposed for use in clinical diagnosis. Classification of vestibular neuronitis into groups A, B and C is suggested on the basis of the reversibility of spontaneous nystagmus after caloric stimulation.