Tinnitus Update.

This article provides an update on tinnitus for audiologists and other clinicians who provide tinnitus-specific services. Tinnitus can be attributable to hearing loss, somatosensory system dysfunction, or auditory cortex dysfunction, with hearing loss being the most common cause and serious underlying pathologies being rare. Hearing loss does not always lead to tinnitus, and patients with tinnitus do not always suffer from hearing loss. The first scenario is explained by a so-called inhibitory gating mechanism, whereas the second assumes that all tinnitus sufferers have some degree of hearing impairment, which might not be detected in standard audiological examinations. The treatments should aim at symptomatic relief and management of associated distress. Current treatment options include pharmacotherapy, education, counseling, cognitive behavioral therapy, and sound therapy.

Efficacy of mastoid oscillation and the Gufoni maneuver for treating apogeotropic horizontal benign positional vertigo: a randomized controlled study.

To determine the immediate and short-term efficacies of mastoid oscillation vs. Gufoni maneuver in treating the apogeotropic type of horizontal canal benign paroxysmal positional vertigo (HC-BPPV), we designed a randomized, prospective, sham-controlled study. In eight dizziness clinics in Korea, 209 consecutive patients with apogeotropic HC-BPPV were enrolled. The patients were randomly assigned to receive a single application of Gufoni (n = 70), mastoid oscillation (n = 67), or sham maneuver (n = 72). Immediate and second-day responses were determined based on the results within 1 h after a single trial of each maneuver and the following day, respectively. Second-day response was assessed in patients who were non-responders on the first day. The short-term response was determined based on the cumulative response for 2 days. Successful treatment was defined as a resolution of positional nystagmus or as a transition into geotropic horizontal nystagmus (not requires vertigo symptom resolution). The immediate responses of the Gufoni maneuver (33/70, 47.1%) and mastoid oscillation (32/67, 47.8%) were better than the sham maneuver (14/72, 19.4%) (p = 0.00). The second-day results did not differ among the three groups (p = 0.76). The short-term responses showed better efficacies with the Gufoni maneuver (51/70, 76.1%) and mastoid oscillation (46/67, 71.9%) than with the sham maneuver (38/72, 53.5%) (p = 0.02). Therapeutic efficacies did not differ between the Gufoni and mastoid oscillation groups in terms of both immediate and short-term outcomes (p = 0.94, 0.57). Both the Gufoni maneuver and mastoid oscillation are valid methods for treating apogeotropic HC-BPPV, with a success rate of approximately 70% for a single maneuver during the short-term follow-up. TRIAL REGISTRATION: clinicaltrials.gov identifier number: NCT02046980.

Autophagy protein 16-mediated autophagy is required for the encystation of Acanthamoeba castellanii.

Autophagy, an evolutionarily conserved protein degradation pathway in eukaryotes, plays essential roles during starvation and cellular differentiation by eliminating unwanted and/or unnecessary cell material including organelles. Autophagy protein 16 (Atg16) is an essential component of the autophagic machinery. The present study identified and characterized an Atg16 homologue (AcAtg16) in Acanthamoeba, an opportunistic pathogen responsible for several distinct diseases in humans. AcAtg16 was highly expressed during encystation and was found to be associated with small or large vesicular structures that partially colocalized with autophagolysosomes. Small interfering RNA against AcAtg16 inhibited autophagosome formation and reduced the encystation efficiency of Acanthamoeba. Moreover, most mitochondria remained undigested in these knockdown cells. Taken together, these results indicate that AcAtg16 is involved in autophagosome formation and plays an essential role in the encystation of Acanthamoeba.

Vestibular rehabilitation therapy: review of indications, mechanisms, and key exercises.

Vestibular rehabilitation therapy (VRT) is an exercise-based treatment program designed to promote vestibular adaptation and substitution. The goals of VRT are 1) to enhance gaze stability, 2) to enhance postural stability, 3) to improve vertigo, and 4) to improve activities of daily living. VRT facilitates vestibular recovery mechanisms: vestibular adaptation, substitution by the other eye-movement systems, substitution by vision, somatosensory cues, other postural strategies, and habituation. The key exercises for VRT are head-eye movements with various body postures and activities, and maintaining balance with a reduced support base with various orientations of the head and trunk, while performing various upper-extremity tasks, repeating the movements provoking vertigo, and exposing patients gradually to various sensory and motor environments. VRT is indicated for any stable but poorly compensated vestibular lesion, regardless of the patient's age, the cause, and symptom duration and intensity. Vestibular suppressants, visual and somatosensory deprivation, immobilization, old age, concurrent central lesions, and long recovery from symptoms, but there is no difference in the final outcome. As long as exercises are performed several times every day, even brief periods of exercise are sufficient to facilitate vestibular recovery. Here the authors review the mechanisms and the key exercises for each of the VRT goals.

Tinnitus: characteristics, causes, mechanisms, and treatments.

Tinnitus-the perception of sound in the absence of an actual external sound-represents a symptom of an underlying condition rather than a single disease. Several theories have been proposed to explain the mechanisms underlying tinnitus. Tinnitus generators are theoretically located in the auditory pathway, and such generators and various mechanisms occurring in the peripheral auditory system have been explained in terms of spontaneous otoacoustic emissions, edge theory, and discordant theory. Those present in the central auditory system have been explained in terms of the dorsal cochlear nucleus, the auditory plasticity theory, the crosstalk theory, the somatosensory system, and the limbic and autonomic nervous systems. Treatments for tinnitus include pharmacotherapy, cognitive and behavioral therapy, sound therapy, music therapy, tinnitus retraining therapy, massage and stretching, and electrical suppression. This paper reviews the characteristics, causes, mechanisms, and treatments of tinnitus.

Predicting a successful treatment in posterior canal benign paroxysmal positional vertigo.

OBJECTIVE: To elucidate the characteristics and prognostic value of positioning nystagmus during the second position of the Epley maneuver (90 degrees contralateral head turn from the initial Hallpike maneuver). METHOD: The Epley maneuver was performed in 126 patients with confirmed posterior canal benign paroxysmal positional vertigo (PC-BPPV). The characteristics of positioning nystagmus were investigated using video Frenzel goggles. RESULTS: During the second position, 99 patients developed torsional upbeating nystagmus, which was in the same direction (orthotropic nystagmus) as during the first position (Hallpike maneuver), whereas 15 patients showed a reversed pattern. In 12 patents, nystagmus was not induced during the second position. All 99 patients with orthotropic nystagmus had resolution of BPPV after the first or second trial of the Epley maneuver. In contrast, 12 of the 15 patients with reversed nystagmus and 8 of the 12 patients without nystagmus failed to resolve. CONCLUSION: During the second position of the Epley maneuver, an orthotropic pattern of nystagmus predicts a successful repositioning, whereas reversed nystagmus or no nystagmus is suggestive of poor response to repositioning.

Acanthamoeba: could it be an environmental host of Shigella?

Shigellosis is a serious public health problem in Korea, because large outbreaks of Shigella sonnei infections were recorded in many parts of the country during the period 1998-2000. However, the epidemiological features of shigellosis are not well known. In this study, we devised conditions suitable for the growth and replication of Shigella in an amoebic intracellular environment, and investigate whether medium conditions affect the survival and replication of Shigella within Acanthamoeba. We evaluated the uptake rates of invasive and non invasive S. sonnei strains by three Acanthamoeba species, namely, A. castellanii Neff, A. astronyxis Ray & Hayes, and A. healyi OC-3A. When A. castellanii Neff was infected with S. sonnei 99OBS1 or 80DH248, shigellae was maintained for a longer time in cytoplasms than in other Acanthamoeba species. S. sonnei 99OBS1 strain (a virulent strain) was recovered in higher numbers than the non-virulent S. sonnei 80DH248 strain in all experiments. Moreover, S. sonnei was more easily engulfed by Acanthamoeba at 18 degrees C. The shigellae uptake rates of Neff strain, which was cultured in free-media (less nutrition), were higher (>10-fold) than those observed in original amoeba culture media (PYG medium) in all time points. S. sonnei 99OBS1 was localized, with an intact membrane, to the vacuoles of Acanthamoeba. We conclude that free-living amoebae more likely act as environmental hosts for shigellae, and thus, may have contributed to outbreaks of shigellosis in Korea.

Nystagmus while recumbent in horizontal canal benign paroxysmal positional vertigo.

BACKGROUND: The identification of the affected ear is crucial for the successful treatment of benign paroxysmal positional vertigo involving the horizontal canal (HC-BPPV) by using particle-repositioning maneuvers. OBJECTIVE: To determine the lateralizing value of lying-down nystagmus in HC-BPPV. METHODS: The authors prospectively investigated lying-down nystagmus in 152 consecutive patients with confirmed HC-BPPV (99 geotropic and 53 apogeotropic types). Lying-down nystagmus was induced by placing patients in a supine position. For the geotropic type of HC-BPPV, the affected ear was identified by assuming that nystagmus is more intense when the head is rotated to the affected side while supine. The reverse assumption was adopted for the apogeotropic type. RESULTS: Lying-down nystagmus was observed in 58 patients (38.2%), 36 (36.4%) of the geotropic and 22 (41.5%) of the apogeotropic type. The direction of lying-down nystagmus was mostly away from the affected ear in the geotropic type, but toward the affected ear in the apogeotropic type. Of the 16 geotropic patients in whom the affected ear was not identified initially, 7 with lying-down nystagmus showed resolution of vertigo after particle-repositioning maneuvers when the involved ear was identified by observing lying-down nystagmus. CONCLUSION: Lying-down nystagmus is a valuable sign for determining which ear is affected in benign paroxysmal positional vertigo involving the horizontal canal, especially when patients show symmetric nystagmus on turning the head to either side.

Successful treatment of vasovagal syncope due to blood-injury phobia by physical maneuvering.

Blood-injury phobia may present as a vasovagal syncope in response to the sight of blood or after receiving venipuncture. A 26-year-old man presented with a history of syncope induced by venipuncture. A transcranial Doppler (TCD) scan with monitoring of both heart rate and blood pressure reproduced the syncope and showed it to be vasovagal in nature. Treatment by practicing physical maneuvers, such as leg crossing and muscle tensing, improved the condition of the patient. This case suggests that physical maneuvering is effective in the treatment of blood-injury phobia.

Transcranial Doppler findings in middle cerebral arterial occlusive disease in relation to degree of stenosis and presence of concomitant stenoses.

PURPOSE: We evaluated the accuracy of transcranial Doppler (TCD) criteria in detecting middle cerebral artery (MCA) stenoses other than solitary severe stenoses. METHODS: Three TCD criteria were evaluated in patients with acute MCA territory infarction who also underwent angiography: abnormalities in mean velocity (MV), focal areas of spectral waveform abnormalities, and compensatory increase in MV in collateral vessels. RESULTS: Among 102 patients studied, angiography revealed MCA lesions in 48: 16 had uncomplicated lesions (single stenosis of moderate to severe degree), 19 had mildly complicated lesions (single MCA stenosis of other than moderate to severe degree, or moderate to severe MCA stenosis with a concomitant lesion outside the MCA), and 13 had severely complicated lesions (MCA stenosis of other than moderate to severe degree with a concomitant lesion outside the MCA). The sensitivity of abnormalities in MV in uncomplicated MCA lesions was 81%, whereas it was 53% in mildly complicated MCA lesions and 38% in severely complicated MCA lesions. However, a compensatory increase in MV in collaterals was more frequently found in complicated MCA lesions, and focal areas of spectral waveform abnormalities were observed fairly consistently in all groups. CONCLUSIONS: TCD findings of focal areas of spectral waveform abnormalities and compensatory collateral flow were common in complicated MCA lesions and may improve the specificity of TCD in the diagnosis of MCA stenosis.