Pharmacological treatment of vertigo

Combination of UPLC-Q-TOF/MS and network pharmacology to reveal the mechanism of Chaihu-jia-Longgu-Muli decoction for treating vertigo with anxiety disorder

Chaihu-jia-Longgu-Muli decoction (CLMD) has been proven clinically effective in treating vertigo with anxiety disorder. However, the mechanism is not clear. This study aimed to explore the mechanism of CLMD in treating vertigo with anxiety disorder based on ultra-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) and network pharmacology. UPLC-Q-TOF/MS was performed to identify the compounds in blood and the targets of compounds of CLMD in vertigo and anxiety were searched using databases. A protein-protein interaction network was built to screen the core targets. The core targets were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. In addition, the vertigo with anxiety rat model was used to verify the results. A total of 22 compounds were absorbed into the blood. Eighty-one potential targets associated with CLMD for vertigo with anxiety disorder were identified through network pharmacological analysis. Subsequently, GO and KEGG analysis showed that CLMD treatment for vertigo with anxiety disorder is associated with neurotransmitter levels and other pertinent physiological processes. The results of the animal experiments showed that CLMD decreased the levels of serotonin, norepinephrine and dopamine, alleviating the symptoms of vertigo and anxiety disorder in model rats. The study revealed CLMD could alleviate vertigo and anxiety symptoms through reducing the levels of neurotransmitters.

Vestibular compensation: Neural mechanisms and clinical implications for the treatment of vertigo

After unilateral peripheral vestibular lesions, the neural activity of neurons in the ipsi-lesional medial vestibular nucleus (ipsi-MVe) are markedly decreased, resulting in static and dynamic asymmetries of the vestibulo-ocular and vestibulo-spinal reflexes. Consequently, static vestibular symptoms such as spontaneous nystagmus and postural deviation and dynamic vestibular symptoms such as oscillopsia and swaying gait are induced. However, these behavioral asymmetries gradually recover after the lesion. Progressive balance restoration is termed vestibular compensation, which is divided into two phases: static and dynamic. Static vestibular compensation is further divided into initial and late processes. In the initial process of static vestibular compensation after unilateral labyrinthectomy (UL) in rats, plastic changes in the cerebello-vestibular and vestibular commissural inhibitory pathways suppress neurons in the contra-lesional MVe (contra-MVe), resulting in the restoration of symmetrical resting activity of MVe neurons on both sides at low levels. The declining frequency of spontaneous nystagmus after UL is an index of the initial process, and short-term administration of diazepam, a GABAA receptor agonist, has been shown to accelerate the initial process in rats. Accordingly, short-term administration of diazepam is recommended for the treatment of acute vertigo in patients with unilateral vestibular dysfunction. In the late process of static vestibular compensation after UL in rats, the resting activity of ipsi-MVe neurons gradually recovers due to changes in cell membrane properties, resulting in the reinforcement of balanced intervestibular nuclear activities to nearly normal levels without the suppression of contra-MVe neurons. The declining number of MK801-induced Fos-positive neurons in contra-MVe after UL is an index of the late process, and long-term administration of betahistine, a histamine H3 receptor antagonist, has been shown to accelerate the late process in rats. Accordingly, long-term administration of betahistine is recommended for the treatment of subacute vertigo in patients who were not compensated for unilateral vestibular dysfunction. In the process of dynamic vestibular compensation after UL, the sensitivity of ipsi-MVe neurons to head velocity and acceleration is restored due to synaptic changes such as long-term potentiation and sprouting of commissures, resulting in the restoration of the dynamic vestibulo-ocular and vestibulo-spinal reflexes. To facilitate dynamic vestibular compensation, early ambulation and subsequent vestibular rehabilitation exercise are recommended for the treatment of chronic vertigo in patients with uncompensated unilateral vestibular dysfunction. Although vestibular compensation after bilateral vestibular loss is not expected, vestibular rehabilitation with a sensory-substitution strategy can improve imbalance in patients with bilateral vestibular lesions.

Comparison of the Efficacy of Vestibular Rehabilitation and Pharmacological Treatment in Benign Paroxysmal Positional Vertigo

Aim: The aim of the study is to compare the effects of vestibular rehabilitation and pharmacological treatment in benign paroxysmal positional vertigo (BPPV). Materials and methods: Thirty patients (40.93 ± 8.66 years old) diagnosed with BPPV were recruited. Patients were equally divided into pharmacological control group and vestibular rehabilitation group. The pharmacological control group was further divided into Group A (n = 8, 2 doses/day, 24 mg betahistine) and Group B (n = 7, 1 dose/day, 50 mg dimenhydrinate in addition to betahistine). Patients in the rehabilitation group underwent repeated head and eye movements, and Epley or Barbecue Roll Maneuvers were applied for 4 weeks. Subjective assessment of vertigo was measured with the visual analog scale. Static balance parameters were measured with the tandem, one-legged stance, and Romberg tests. Dynamic visual acuity was measured with a Snellen chart, and vestibular dysfunction was measured with the Unterberger (Fukuda stepping) test. All parameters were evaluated before and after treatment. Results: Vestibular rehabilitation resulted in greater improvement in severity of vertigo, balance parameters except Romberg test, and vestibular dysfunction than pharmacological therapy (p < 0,001). There was no significant difference in dynamic visual acuity between groups (p = 0,24). The effects of medication with the active ingredients betahistine and dimenhydrinate were similar (p > 0,05). Conclusion: The vestibular rehabilitation method can positively change the severity of vertigo, balance ability, and vestibular dysfunction compared to pharmacological therapy. Dimenhydrinate administered in combination with betahistine was not superior to betahistine alone but can be recommended for its antiemetic effect.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-03598-4.

Potential effects of cannabinoids on audiovestibular function: A narrative review

The growing interest in the development of drugs that target the endocannabinoid system has extended to conditions that affect the audiovestibular pathway. The expression of cannabinoid (CB) receptors in that pathway has been widely demonstrated, indicating a therapeutic potential for drug development at this level. These medications may be beneficial for conditions such as noise-induced hearing loss, ototoxicity, or various forms of vertigo of central or peripheral origin. The therapeutic targets of interest include natural or synthetic compounds that act as CB1/CB2 receptor agonists/antagonists, and inhibitors of the endocannabinoid-degrading enzymes FAAH and MAGL. Furthermore, genetic variations implicated in the response to treatment and the development of related disorders such as epilepsy or migraine have been identified. Direct methods of administering these medications should be examined beyond the systemic strategy.

Decreased vestibular efficacy contributes to abnormal balance in Parkinson's disease

BACKGROUND AND PURPOSE

Abnormal balance is poorly responsive to dopaminergic therapy in Parkinson's disease (PD). Decreased vestibular efficacy may contribute to imbalance in PD. The purpose of this study was to investigate the relationship between vestibular measures of dynamic posturography and imbalance in PD while accounting for confounder variables.

METHODS

106 patients with PD underwent dynamic posturography for the 6 conditions of the sensory integration test (SOT) using the Neurocom Equitest device. All SOT measures, nigrostriatal dopaminergic denervation ((+)-[11C]DTBZ PET), brain acetylcholinesterase ([11C]PMP PET), age, duration of disease, cognitive and parkinsonian motor scores, and ankle vibration sensitivity were used as regressors in a stepwise logistic regression model comparing PD patients with versus without imbalance defined as Hoehn and Yahr (HY) stage 2.5 or higher.

RESULTS

The presence of imbalance was significantly associated with vestibular ratio COP RMS (P = 0.002) independently from visual ratio COP velocity (P = 0.012), thalamic acetylcholinesterase activity (P = 0.0032), cognition (P = 0.006), motor severity (P = 0.0039), age (P = 0.001), ankle vibration sensitivity (P = 0.0008), and borderline findings for somatosensory ratio COP velocity (P = 0.074) and visual ratio COP RMS (P = 0.078). Nigrostriatal dopaminergic denervation did not achieve significance.

CONCLUSIONS

The inability to efficaciously utilize vestibular information to retain upright stance is a determinant of imbalance in PD independent from visual and somatosensory processing changes and nigrostriatal dopaminergic losses. Thalamic, but not cortical, cholinergic denervation incrementally predicted balance abnormality. Further research is needed to investigate an intrinsic role of the cholinergic thalamus in multi-sensory, in particular vestibular, processing functions of postural control in PD.

The pharmacological treatment of acute vestibular syndrome

Acute vestibular syndrome (AVS) represents a clinical picture that involves urgent management due to the important procession of symptoms accompanying the event, which can be positively or negatively influenced by therapeutic choices and intervention timing. This forces a differential diagnosis and therapeutic choices to be made in conditions that are not always favorable and often not in the specialist field. In this work, we will examine in detail the pharmacological therapeutic possibilities, correlating them to the differential and, as far as possible, to the etiological diagnosis. In particular, the pharmacological possibilities for the two main conditions we can face will be investigated, namely, vestibular neuritis and posterior circulation stroke.

Efficacy of Benzodiazepines or Antihistamines for Patients With Acute Vertigo: A Systematic Review and Meta-analysis

Importance

Acute vertigo can be disabling. Antihistamines and benzodiazepines are frequently prescribed as "vestibular suppressants," but their efficacy is unclear.

Objective

To assess the efficacy of antihistamines and benzodiazepines in the treatment of acute vertigo from any underlying cause.

Data Sources

We searched the PubMed, CENTRAL, EMBASE, CINAHL, Scopus, and ClinicalTrials.gov databases from inception to January 14, 2019, without language restrictions. Bibliographies of the included studies and relevant reviews were also screened.

Study Selection

We included randomized clinical trials (RCTs) comparing antihistamine or benzodiazepine use with another comparator, placebo, or no intervention for patients with a duration of acute vertigo for 2 weeks or less. Studies of healthy volunteers, prophylactic treatment, or induced vertigo were excluded, as were studies that compared 2 medications from the same class.

Data Extraction and Synthesis

Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, data were extracted and risk of bias was assessed by 2 authors independently for each study. Data were pooled using a random-effects model.

Main Outcomes and Measures

The predefined primary outcome was change in 10- or 100-point vertigo or dizziness visual analog scale (VAS) scores at 2 hours after treatment. Secondary outcomes included change in nausea VAS scores at 2 hours, use of rescue medication at 2 hours, and improvement or resolution of vertigo at 1 week or 1 month.

Results

Of the 27 trials identified in the systematic review, 17 contributed to the quantitative meta-analysis and involved a total of 1586 participants. Seven trials with a total of 802 participants evaluated the primary outcome of interest: single-dose antihistamines resulted in significantly more improvement on 100-point VAS scores compared with benzodiazepines (difference, 16.1 [95% CI, 7.2 to 25.0]) but not compared with other active comparators (difference, 2.7 [95% CI, -6.1 to 11.5]). At 1 week and 1 month, neither daily benzodiazepines nor antihistamines were reported to be superior to placebo. RCTs comparing the immediate effects of medications (at 2 hours) after a single dose generally had a low risk of bias, but those evaluating 1-week and 1-month outcomes had a high risk of bias.

Conclusions and Relevance

Moderately strong evidence suggests that single-dose antihistamines provide greater vertigo relief at 2 hours than single-dose benzodiazepines. Furthermore, the available evidence did not support an association of benzodiazepine use with improvement in any outcomes for acute vertigo. Other evidence suggested that daily antihistamine use may not benefit patients with acute vertigo. Larger randomized trials comparing both antihistamines and benzodiazepines with placebo could better clarify the relative efficacy of these medications.

Accuracy of Tools to Differentiate Single From Recurrent Fallers Pre-Frail Older Women

Objectives

The objectives of this study were to analyze and compare musculoskeletal and functional performance and present cutoff points to differentiate pre-frail community-dwelling older women regarding their fall history: non fallers (0 falls), fallers (single fall), and recurrent fallers (≥2 falls).

Method

This is a cross-sectional, retrospective study on 90 pre-frail community-dwelling older women (71.2 ± 4.49 years) according to Fried criteria. We assessed peak torque (PT) (isokinetic dynamometer), muscle architecture/mass (ultrasound/dual-energy X-ray absorptometry), and the following functional performance: usual gait speed (UGS), fast gait speed (FGS), walking speed reserve (WSR), cadence and step length, and timed up and go.

Results

The recurrent fallers presented lower UGS (1.12 ± 0.18 vs. 1.29 ± 0.28 m/s; p = 0.05) and isometric PT of knee extensors than the fallers (89.88 ± 20.99 vs. 115.55 ± 23.09 Nm; p = 0.01), and lower FGS than the fallers (1.35 ± 0.26 vs. 1.5 ± 0.29 m/s; p = 0.03) and non-fallers (1.35 ± 0.26 vs. 1.52 ± 0.26 m/s; p = 0.01). The outcomes that differentiated the fallers from the non-fallers were both WSR calculated as a difference (WSRdiff) (≤0.26 m/s) and WSR calculated as a ratio (WSRratio) (≤1.25 m/s), while to differentiate the recurrent fallers from the non-fallers were FGS (≤1.44 m/s) and step length (≤73 cm). The following cutoff points might be used to differentiate recurrent fallers and fallers: UGS (≤1.12 m/s), FGS (≤1.34m/s), step length (≤73 cm), PT knee extension (≤114.2 Nm), PT knee flexion (≤46.3 Nm), and PT ankle dorsiflexion (≤22.1 Nm).

Conclusion

Recurrent fallers community-dwelling pre-frail older women presented a worse musculoskeletal and functional performance when compared to the non-fallers and fallers. Gait speed, step length, PT of both knee extension and flexion, and ankle dorsiflexion can be used to identify both single and recurrent fallers pre-frail older women, contributing to guide interventions and prevent falls and fractures.

Drug-Drug Interactions in Vestibular Diseases, Clinical Problems, and Medico-Legal Implications

Peripheral vestibular disease can be treated with several approaches (e.g., maneuvers, surgery, or medical approach). Comorbidity is common in elderly patients, so polytherapy is used, but it can generate the development of drug-drug interactions (DDIs) that play a role in both adverse drug reactions and reduced adherence. For this reason, they need a complex kind of approach, considering all their individual characteristics. Physicians must be able to prescribe and deprescribe drugs based on a solid knowledge of pharmacokinetics, pharmacodynamics, and clinical indications. Moreover, full information is required to reach a real therapeutic alliance, to improve the safety of care and reduce possible malpractice claims related to drug-drug interactions. In this review, using PubMed, Embase, and Cochrane library, we searched articles published until 30 August 2021, and described both pharmacokinetic and pharmacodynamic DDIs in patients with vestibular disorders, focusing the interest on their clinical implications and on risk management strategies.

Current Insights into Treating Vertigo in Older Adults

The number of older people has been increasing over recent decades in Western populations. Dizziness, imbalance, and vertigo constitute some of the most common complaints in older patients, and risk of falling is the most frequent and worrying consequence. It has been reported that 15–20% of the adult population experiences these debilitating symptoms. Among the diseases that may be associated with vertigo, the three classes of otological, central, and functional (psychological) dizziness may be distinguished. Overall, vestibular disorders account for 48% of vertiginous complaints in the older population. The main focus of this article is to review the forms of pharmacotherapy for vertigo, especially with regard to older patients, who may be treated simultaneously with other drugs for different comorbidities. Interactions with other drugs should be considered in the choice of a particular course of treatment. Moreover, overuse of pharmacotherapy for the management of vertigo in the elderly may prevent the development of the central compensatory mechanism that sustains both static and dynamic imbalance after a vertiginous crisis. In the majority of patients, vestibular and physical rehabilitation are strongly advised and rarely contraindicated.

Efficacy and Pharmacological Appropriateness of Cinnarizine and Dimenhydrinate in the Treatment of Vertigo and Related Symptoms

Vertigo is not itself a disease, but rather a symptom of various syndromes and disorders that jeopardize balance function, which is essential for daily activities. It is an abnormal sensation of motion that usually occurs in the absence of motion, or when a motion is sensed inaccurately. Due to the complexity of the etiopathogenesis of vertigo, many pharmacological treatments have been tested for efficacy on vertigo. Among these drugs, cinnarizine, usually given together with dimenhydrinate, appears to be the first-line pharmacotherapy for the management of vertigo and inner ear disorders. Based on these considerations, the present non-interventional study aimed to investigate the clinical efficacy and tolerability of a fixed combination of cinnarizine (20 mg) and dimenhydrinate (40 mg) in patients suffering from vertigo-related symptoms. To this end, we enrolled 120 adults-70 males, and 50 females-with an average age of 64 years. Before beginning pharmacological treatment, all patients were screened for the intensity of vertigo, dizziness, and concomitant symptoms through the Visual Scale of Dizziness Disorders and Dizziness Handicap Inventory scales. At the end of the anamnestic evaluation, patients received the fixed-dose combination of cinnarizine (20 mg) plus dimenhydrinate (40 mg) 3 times daily, for 60 days. The results of this study provide further insight regarding the efficacy of the fixed combination when used to reduce symptoms of vestibular vertigo of central and/or peripheral origin, after both the 15- and 60-day therapies. Independent of the type of vertigo, the fixed combination was able to reduce dizziness- and vertigo-associated symptoms in more than 75% of all patients treated, starting from 15 days of therapy, and improving 60 days after starting the therapy. Interestingly, we also found differences between male and female patients in the framework of the pharmacological effects of therapy. This study provides further details concerning the therapeutic efficacy of the fixed combination of cinnarizine and dimenhydrinate, and also focuses attention on the possibility that these drugs could act in a gender-specific manner, paving the way for further research.

The effectiveness of propranolol, flunarizine, amitriptyline and botulinum toxin in vestibular migraine complaints and prophylaxis: a non-randomized controlled study

Introduction

Vestibular migraine is the most common cause of spontaneous episodic vertigo in adult patients and the second most common cause of vertigo in patients of all ages.

Objective

To assess the effectiveness of oral medication type (propranolol, flunarizine, and amitriptyline) and botulinum toxin A application on vestibular symptoms, headache severity and attack frequency for vestibular migraine patients.

Methods

Sixty patients with vestibular migraine were enrolled. Thirty patients received botulinum toxin A treatment (B+ group) in addition to the oral medication, whereas 30 patients received only oral medication (B− group). Headache severity was evaluated with Migraine Disability Assessment Scale and vertigo severity was evaluated with Dizziness Handicap Inventory scale. Vestibular migraine attack frequencies in the last three months were also evaluated.

Results

There was a statistically significant decrement in mean Dizziness Handicap Inventory scores, Migraine Disability Assessment Scale scores and vertigo attack frequencies after treatment for all patients, B+ and B− group patients (p < 0.001 for all). The mean Migraine Disability Assessment Scale score gains (p < 0.001) and vertigo attack frequency gains (p =  0.003) were significantly higher in the B+ patients than B− patients.

Conclusions

Both B+ and B− group patients exhibited significant improvement in vestibular migraine attack frequencies, Dizziness Handicap Inventory score and Migraine Disability Assessment Scale score values. However, botulinum toxin A application had a more pronounced effect for Migraine Disability Assessment Scale score gain and vestibular migraine attack frequency values, but not for Dizziness Handicap Inventory score gain values. Thus, botulinum toxin A application should be considered for vestibular migraine patients whose headache severity degrees are more profound. The oral medication type (propranolol, flunarizine or amitriptyline) did not differ in influencing the vestibular migraine attack frequency, Dizziness Handicap Inventory score gain and Migraine Disability Assessment Scale score gain values.

Comparison of efficacy dimenhydrinate and metoclopramide in the treatment of nausea due to vertigo; a randomized study

BACKGROUND

This study aimed to compare the therapeutic efficacy of dimenhydrinate and metoclopramide in patients with nausea and vertigo.

METHODS

A prospective, double-blind, randomized clinical trial was performed on patients who presented to the emergency department (ED) with nausea and vertigo in the six month period between Nov 1st 2012 and May 1st 2013. Adult patients who were 18 to 65 years old presenting to the ED with nausea and vertigo or motion sickness were included in the study. A total of 200 patients were divided into 2 groups who were admitted to ED with complaints of vertigo accompanied by nausea. In the first group, 50 mg dimenhydrinate and 10 mg metoclopramide infusions were given intravenously for 15 min. The efficacy of treatment was measured by using a 10 mm Visual Analog Scale (VAS) performed at 0, 15 and the 30th minute. The primary outcome variable was a reduction in vertigo intensity documented on the VAS at the 30th minute after medication administration.

RESULTS

A total of 200 patients were included in the randomization (n=100 in both groups). The baseline vertigo VAS scores were 7.57±1.42 in the dimenhydrinate (DMT) group and 7.27±1.40 in the metoclopramide (MTP) group (p=0.09). In the 30th minute of treatment, the average vertigo VAS score was 2.46 ± 2.39 in the DMT group and 2.31±1.96 in the MTP group; no significant differences were detected between groups. The baseline nausea VAS scores were 7.62±1.48 in the DMT group and 7.45±1.27 in the MTP group (p=0.36). In the 30th minute of treatment the average vertigo VAS score decreased to 2.27±2.24 in the DMT group and 2.70±2.48 in the MTP group, no significant differences were detected between groups. No significant differences were detected between nausea VAS changes and vertigo VAS changes at 30th minutes of the treatment (p=0.06, p=0.85 respectively). Rescue medication need was similar in both treatment groups (p=0.94). No significant differences were detected about the side effects which are sedation (p=0.56) and hypotension (p=0.57).

CONCLUSIONS

In conclusion, this prospective, double-blind, randomized study showed that both DMT and MTP have similar efficacy in reducing nausea and vertigo symptoms in the ED.

Treatment of Vestibular Migraine: A Systematic Review and Meta-analysis

OBJECTIVE

To assess the efficacy of the various therapies used for the prevention of vestibular migraine (VM).

METHODS

Primary studies were identified though PubMed, Scopus, PsycINFO, and Cochrane Library by two independent investigators for articles published through April 2019. The search identified randomized comparison or observational studies pertaining to vestibular migraine treatment. Meta-analysis was performed on pre- and posttreatment Dizziness Handicap Inventory, vertigo frequency, and percentage of perceived improvement.

RESULTS

Literature search identified 13 studies that reported sufficient outcome measures to be included in the analysis. Patients with VM had a mean age of 43.3 years with female-to-male gender ratio of 2.1:1. Classes of therapeutic agents included antiepileptic drugs, calcium channel blockers, tricyclic antidepressants, β-blockers, serotonin and norepinephrine reuptake inhibitors, and vestibular rehabilitation. All treatment options that were analyzed demonstrated improvement in all of the outcome parameters, but due to significant heterogeneity and lack of standardized reporting on outcomes, establishment of preferred treatment modality could not be determined.

CONCLUSIONS

Various treatment modalities have been evaluated for preventative treatment of VM. Physician familiarity, patient comorbidities, and the side-effect profiles of various interventions likely influence the selection of intervention. Future randomized controlled trials with restrictive inclusion criteria and generalizable standardized outcome measures will allow for more robust meta-analyses and for more evidence-based treatment of vestibular migraines. Laryngoscope, 131:186-194, 2021.

Comparing the Effects of Epley Maneuver and Cinnarizine on Benign Positional Paroxysmal Vertigo; A Randomized Clinical Trial

Background:

The fastest and safest treatment method of BPPV is repositioning maneuvers. In Iran, this methods are not widely used, and many physicians use medical therapy, despite their side effects, for management of BPPV.

Materials and Methods:

In this randomized clinical trial patients with BPPV were randomly allocated to Epley repositioning maneuver or Cinnarizine (25mg every 8 hours) for two weeks. The patients were evaluated for symptoms using visual analogue scale (VAS) scoring system before intervention, first and second weeks after intervention. In the second and third visitd the results of hallpike test was recorded for both groups.

Results:

43 patients with a mean age of 46.88±11.08 years in two Epley and Cinnarizine group underwent analysis. The mean VAS score for improvement of symptoms after intervention was 1.66±1.06 in Epley and 1.50±0.91 in Cinnarizine group (P=0.57).

Conclusion:

we found that there is no significant difference between Epley maneuver and Cinnarizine for treatment and controlling symptoms of BPPV.

Rehabilitation Assessment and Management of Neurosensory Deficits After Traumatic Brain Injury in the Polytrauma Veteran

Neurosensory deficits after traumatic brain injury can frequently lead to disability; therefore, diagnosis and treatment are important. Posttraumatic headaches typically resemble migraines and are managed similarly, but adjuvant physical therapy may be beneficial. Sleep-related issues are treated pharmacologically based on the specific sleep-related complaint. Fatigue is difficult to treat; cognitive behavioral therapy and aquatic therapy can be beneficial. Additionally, methylphenidate and modafinil have been used. Peripheral and central vestibular dysfunction causes dizziness and balance dysfunction, and the mainstay of treatment is vestibular physical therapy. Visual dysfunction incorporates numerous different diagnoses, which are frequently treated with specific rehabilitation programs.

Anticholinergic and sedative medications and the risk of vertigo or dizziness in the German primary care setting-A matched case-control study from the CONTENT registry

PURPOSE

To date, there is little information on the utilization of anticholinergic and sedative (AS) medications to vertigo or dizziness (VoD) patients in the German primary care setting. The objective of this study was to evaluate AS medication use and its association with VoD within the German primary care setting.

METHODS

Cases with VoD from the CONTENT (CONTinuous morbidity registration Epidemiologic NeTwork) database were 1:1 matched to controls on age, sex, and comorbidities by propensity score matching. AS medication was defined using the fourth level of Anatomical Therapeutic Chemical Classification (ATC) Codes. A prescription of AS medication any time within the study period formed the primary exposure. Multivariable conditional logistic regression examined the association between AS use and VoD.

RESULTS

Of a total of N = 151 446 patients, 6971 (4.6%) cases and 6971 corresponding controls were analyzed (mean age (sd): 59.9 years (20.9), 64.2% female). Dizziness and giddiness (ICD-10 Code R42) were diagnosed most prominently (87.2%). AS medication was prescribed on 1072 of 10 552 (10.2%) consultation days with VoD diagnoses. After adjusting for covariates, AS use was significantly and independently associated with VoD, adjusted odds ratio (1.37; 95% CI: 1.18-1.58), compared with no AS use.

CONCLUSION

Primary care practitioners should consider AS medication as a risk factor for VoD and avoid prescribing AS medications after a VoD diagnosis. Caution should also be taken when prescribing AS medications to older adults (≥65 years). Systematical calculations of AS medication burden for patients could help acknowledge this issue and raise awareness for prescription habits in primary care.

Betahistine Treatment in a Cat Model of Vestibular Pathology: Pharmacokinetic and Pharmacodynamic Approaches

This study is a pharmacokinetic (PK) and pharmacodynamics (PD) approach using betahistine doses levels in unilateral vestibular neurectomized cats (UVN) comparable to those used in humans for treating patients with Menière's disease. The aim is to investigate for the first time oral betahistine administration (0.2 and 2 mg/kg/day) with plasma concentrations of betahistine and its major metabolite 2-pyridylacetic acid (2-PAA) (N = 9 cats), the time course of posture recovery (N = 13 cats), and the regulation of the enzyme synthesizing histamine (histidine decarboxylase: HDC) in the tuberomammillary nuclei (TMN) of UVN treated animals (N = the same 13 cats plus 4 negative control cats). In addition the effect of co-administration of the lower betahistine dose (0.2 mg/kg/day) and selegiline (1 mg/kg/day), an inhibitor of the monamine oxidase B (MAOBi) implicated in betahistine catabolism was investigated. The PK parameters were the peak concentration (C_max), the time when the maximum concentration is reached (T_max) for both betahistine and 2-PAA and the area under the curve (AUC). The PD approach consisted at quantifying the surface support area, which is a good estimation of posture recovery. The plasma concentration-time-profiles of betahistine and 2-PAA in cats were characterized by early C_max-values followed by a phase of rapid decrease of plasma concentrations and a final long lasting low level of plasma concentrations. Co administration of selegiline and betahistine increased values of C_max and AUC up to 146- and 180-fold, respectively. The lowest dose of betahistine (0.2 mg/kg) has no effects on postural function recovery but induced an acute symptomatic effect characterized by a fast balance improvement (4–6 days). The higher dose (2 mg/kg) and the co-administration treatment induced both this acute effect plus a significant acceleration of the recovery process. The histaminergic activity of the neurons in the TMN was significantly increased under treatment with the 2 mg/kg betahistine daily dose, but not with the lower dose alone or in combination with selegiline. The results show for the first time that faster balance recovery in UVN treated cats is accompanied with high plasma concentrations of betahistine and 2-PAA, and upregulation of HDC immunopositive neurons in the TMN. The higher betahistine dose gives results similar to those obtained with the lower dose when co-administrated with an inhibitor of betahistine metabolism, selegiline. From a clinical point of view, the study provides new perspectives for Menière's disease treatment, regarding the daily betahistine dose that should be necessary for fast and slow metabolizers.

Antivertiginous drug therapy does not hinder the efficacy of individualized vibrotactile neurofeedback training for vestibular rehabilitation - a randomized trial

Vestibular rehabilitation using individualized vibrotactile neurofeedback training (IVNT) can lead to significant improvement in the postural stability of patients with vestibular symptoms of different origins. However, some of these patients have complex, severe dizziness, meaning that a pharmacological pretreatment or parallel (to vestibular rehabilitation) treatment can help them perform the rehabilitation exercises. Hence, the present study investigated the influence of a pharmacological treatment on the efficacy of vibrotactile neurofeedback training in patients with chronic, noncompensated vestibulopathies. All participants performed IVNT for ∼10 min each day for 2 weeks. In addition, every second participant was selected randomly to receive oral medication (20 mg cinnarizine and 40 mg dimenhydrinate per tablet), taking three tables per day. Trunk and ankle sway and postural stability were measured. In addition, the dizziness handicap inventory was evaluated immediately before training on the last day of training and 6 months after training. After the 10-day period of IVNT, both groups showed a statistically significant improvement in all parameters tested. A follow-up analysis after 6 months showed a long-term efficacy for the IVNT, that is, the patients remained significantly improved in their postural stability. The antivertiginous therapy did not hinder the efficacy of the IVNT. The present results indicate that IVNT even in combination with an antivertiginous drug therapy is an effective treatment regime for patients with disabling vertigo of different origins.

Teaching Patient-Centered Counseling Skills for Assessment, Diagnosis, and Management of Benign Paroxysmal Positional Vertigo

Audiologists are an integral part of the management of those with dizziness and vestibular disorders. However, little research has been performed on counseling approaches for patients who present with dizziness as a primary concern. Accordingly, it is important that audiology students are provided with didactic and experiential learning opportunities for the assessment, diagnosis, and management of this population. Benign paroxysmal positional vertigo is the most common vestibular disorder among adults. Doctor of Audiology students, at a minimum, should be provided with learning opportunities for counseling patients with this particular disorder. Implementation of patient-centered counseling is applied across various parts of the patient encounter from initial intake to treatment and patient education. The purpose of this article is to present the available evidence and to apply widely accepted theories and techniques to counseling those with benign paroxysmal positional vertigo. Didactic resources and experiential learning activities are provided for use in coursework or as a supplement to clinical education.

‘Brain shivers': from chat room to clinic

The internet is rapidly becoming a first-line source for clinicians and patients alike, and it is increasingly necessary that clinicians maintain an open dialogue with their patients about their information sources. In this paper, I look at the emergence of ‘brain shivers' as a side-effect that appears to have emerged online, in the context of antidepressant side-effects and withdrawal. I discuss possible biological explanations for this strange, possibly new, complaint, as well as the emergence of particular symptoms as a sociological phenomenon aided by new technology.

Neuropharmacological Targets for Drug Action in Vestibular Sensory Pathways

The use of pharmacological agents is often the preferred approach to the management of vestibular dysfunction. In the vestibular sensory pathways, the sensory neuroepithelia are thought to be influenced by a diverse number of neuroactive substances that may act to enhance or inhibit the effect of the primary neurotransmitters [i.e., glutamate (Glu) and acetylcholine (ACh)] or alter their patterns of release. This review summarizes various efforts to identify drug targets including neurotransmitter and neuromodulator receptors in the vestibular sensory pathways. Identifying these receptor targets provides a strategic basis to use specific pharmacological tools to modify receptor function in the treatment and management of debilitating balance disorders. A review of the literature reveals that most investigations of the neuropharmacology of peripheral vestibular function have been performed using in vitro or ex vivo animal preparations rather than studying drug action on the normal intact vestibular system in situ. Such noninvasive approaches could aid the development of more accurate and effective intervention strategies for the treatment of dizziness and vertigo. The current review explores the major neuropharmacological targets for drug action in the vestibular system.

Discovery and Development of Calcium Channel Blockers

In the mid 1960s, experimental work on molecules under screening as coronary dilators allowed the discovery of the mechanism of calcium entry blockade by drugs later named calcium channel blockers. This paper summarizes scientific research on these small molecules interacting directly with L-type voltage-operated calcium channels. It also reports on experimental approaches translated into understanding of their therapeutic actions. The importance of calcium in muscle contraction was discovered by Sidney Ringer who reported this fact in 1883. Interest in the intracellular role of calcium arose 60 years later out of Kamada (Japan) and Heibrunn (USA) experiments in the early 1940s. Studies on pharmacology of calcium function were initiated in the mid 1960s and their therapeutic applications globally occurred in the the 1980s. The first part of this report deals with basic pharmacology in the cardiovascular system particularly in isolated arteries. In the section entitled from calcium antagonists to calcium channel blockers, it is recalled that drugs of a series of diphenylpiperazines screened in vivo on coronary bed precontracted by angiotensin were initially named calcium antagonists on the basis of their effect in depolarized arteries contracted by calcium. Studies on arteries contracted by catecholamines showed that the vasorelaxation resulted from blockade of calcium entry. Radiochemical and electrophysiological studies performed with dihydropyridines allowed their cellular targets to be identified with L-type voltage-operated calcium channels. The modulated receptor theory helped the understanding of their variation in affinity dependent on arterial cell membrane potential and promoted the terminology calcium channel blocker (CCB) of which the various chemical families are introduced in the paper. In the section entitled tissue selectivity of CCBs, it is shown that characteristics of the drug, properties of the tissue, and of the stimuli are important factors of their action. The high sensitivity of hypertensive animals is explained by the partial depolarization of their arteries. It is noted that they are arteriolar dilators and that they cannot be simply considered as vasodilators. The second part of this report provides key information about clinical usefulness of CCBs. A section is devoted to the controversy on their safety closed by the Allhat trial (2002). Sections are dedicated to their effect in cardiac ischemia, in cardiac arrhythmias, in atherosclerosis, in hypertension, and its complications. CCBs appear as the most commonly used for the treatment of cardiovascular diseases. As far as hypertension is concerned, globally the prevalence in adults aged 25 years and over was around 40% in 2008. Usefulness of CCBs is discussed on the basis of large clinical trials. At therapeutic dosage, they reduce the elevated blood pressure of hypertensive patients but don't change blood pressure of normotensive subjects, as was observed in animals. Those active on both L- and T-type channels are efficient in nephropathy. Alteration of cognitive function is a complication of hypertension recognized nowadays as eventually leading to dementia. This question is discussed together with the efficacy of CCBs in cognitive pathology. In the section entitled beyond the cardiovascular system, CCBs actions in migraine, neuropathic pain, and subarachnoid hemorrhage are reported. The final conclusions refer to long-term effects discovered in experimental animals that have not yet been clearly reported as being important in human pharmacotherapy.

Clinical Practice Guideline: Benign Paroxysmal Positional Vertigo (Update)

Objective

This update of a 2008 guideline from the American Academy of Otolaryngology—Head and Neck Surgery Foundation provides evidence-based recommendations to benign paroxysmal positional vertigo (BPPV), defined as a disorder of the inner ear characterized by repeated episodes of positional vertigo. Changes from the prior guideline include a consumer advocate added to the update group; new evidence from 2 clinical practice guidelines, 20 systematic reviews, and 27 randomized controlled trials; enhanced emphasis on patient education and shared decision making; a new algorithm to clarify action statement relationships; and new and expanded recommendations for the diagnosis and management of BPPV.

Purpose

The primary purposes of this guideline are to improve the quality of care and outcomes for BPPV by improving the accurate and efficient diagnosis of BPPV, reducing the inappropriate use of vestibular suppressant medications, decreasing the inappropriate use of ancillary testing such as radiographic imaging, and increasing the use of appropriate therapeutic repositioning maneuvers. The guideline is intended for all clinicians who are likely to diagnose and manage patients with BPPV, and it applies to any setting in which BPPV would be identified, monitored, or managed. The target patient for the guideline is aged ≥18 years with a suspected or potential diagnosis of BPPV. The primary outcome considered in this guideline is the resolution of the symptoms associated with BPPV. Secondary outcomes considered include an increased rate of accurate diagnoses of BPPV, a more efficient return to regular activities and work, decreased use of inappropriate medications and unnecessary diagnostic tests, reduction in recurrence of BPPV, and reduction in adverse events associated with undiagnosed or untreated BPPV. Other outcomes considered include minimizing costs in the diagnosis and treatment of BPPV, minimizing potentially unnecessary return physician visits, and maximizing the health-related quality of life of individuals afflicted with BPPV.

Action Statements

The update group made strong recommendations that clinicians should (1) diagnose posterior semicircular canal BPPV when vertigo associated with torsional, upbeating nystagmus is provoked by the Dix-Hallpike maneuver, performed by bringing the patient from an upright to supine position with the head turned 45° to one side and neck extended 20° with the affected ear down, and (2) treat, or refer to a clinician who can treat, patients with posterior canal BPPV with a canalith repositioning procedure. The update group made a strong recommendation against postprocedural postural restrictions after canalith repositioning procedure for posterior canal BPPV. The update group made recommendations that the clinician should (1) perform, or refer to a clinician who can perform, a supine roll test to assess for lateral semicircular canal BPPV if the patient has a history compatible with BPPV and the Dix-Hallpike test exhibits horizontal or no nystagmus; (2) differentiate, or refer to a clinician who can differentiate, BPPV from other causes of imbalance, dizziness, and vertigo; (3) assess patients with BPPV for factors that modify management, including impaired mobility or balance, central nervous system disorders, a lack of home support, and/or increased risk for falling; (4) reassess patients within 1 month after an initial period of observation or treatment to document resolution or persistence of symptoms; (5) evaluate, or refer to a clinician who can evaluate, patients with persistent symptoms for unresolved BPPV and/or underlying peripheral vestibular or central nervous system disorders; and (6) educate patients regarding the impact of BPPV on their safety, the potential for disease recurrence, and the importance of follow-up. The update group made recommendations against (1) radiographic imaging for a patient who meets diagnostic criteria for BPPV in the absence of additional signs and/or symptoms inconsistent with BPPV that warrant imaging, (2) vestibular testing for a patient who meets diagnostic criteria for BPPV in the absence of additional vestibular signs and/or symptoms inconsistent with BPPV that warrant testing, and (3) routinely treating BPPV with vestibular suppressant medications such as antihistamines and/or benzodiazepines. The guideline update group provided the options that clinicians may offer (1) observation with follow-up as initial management for patients with BPPV and (2) vestibular rehabilitation, either self-administered or with a clinician, in the treatment of BPPV.

Diazepam and Meclizine Are Equally Effective in the Treatment of Vertigo: An Emergency Department Randomized Double-Blind Placebo-Controlled Trial

BACKGROUND

Vertigo is a debilitating disease that is commonly encountered in the emergency department (ED). Diazepam and meclizine are oral medications that are commonly used to alleviate symptoms.

OBJECTIVES

We sought to determine whether meclizine or diazepam is superior in the treatment of patients with peripheral vertigo in the ED.

METHODS

We performed a double-blind clinical trial at a suburban, teaching ED. We randomized a convenience sample of adult patients with acute peripheral vertigo (APV) to diazepam 5 mg or meclizine 25 mg orally. Demographic and historical features were recorded on a standardized data form. Patients recorded their initial level (t0) of vertigo on a 100-mm visual analog scale (VAS) and after 30 min (t30) and 60 min (t60). The primary outcome parameter was the mean change in VAS score from t0 to t60. Differences between groups and 95% confidence intervals were calculated. Our a priori power calculation estimated that a sample size of 20 patients in each group was required to have an 80% power to detect a difference of 20 mm between treatment groups.

RESULTS

There were 20 patients in the diazepam group and 20 in the meclizine group. The two groups were similar with respect to patient demographics and presenting signs and symptoms. At t60, the mean improvements in the diazepam and meclizine groups were 36 and 40, respectively (difference -4; 95% confidence interval -20 to 12; p = 0.60).

CONCLUSION

We found no difference between oral diazepam and oral meclizine for the treatment of ED patients with acute peripheral vertigo.

Excitatory effect of norepinephrine on neurons in the inferior vestibular nucleus and the underlying receptor mechanism

The central noradrenergic system, originating mainly from the locus coeruleus in the brainstem, plays an important role in many physiological functions, including arousal and attention, learning and memory, anxiety, and nociception. However, little is known about the roles of norepinephrine (NE) in somatic motor control. Therefore, using extracellular recordings on rat brainstem slices and quantitative real-time RT-PCR, we investigate the effect and mechanisms of NE on neuronal activity in the inferior vestibular nucleus (IVN), the largest nucleus in the vestibular nuclear complex, which holds an important position in integration of information signals controlling body posture. Here, we report that NE elicits an excitatory response on IVN neurons in a concentration-dependent manner. Activation of α1 - and β2 -adrenergic receptors (ARs) induces an increase in firing rate of IVN neurons, whereas activation of α2 -ARs evokes a decrease in firing rate of IVN neurons. Therefore, the excitation induced by NE on IVN neurons is a summation of the excitatory components mediated by coactivation of α1 - and β2 -ARs and the inhibitory component induced by α2 -ARs. Accordingly, α1 -, α2 -, and β2 -AR mRNAs are expressed in the IVN. Although β1 -AR mRNAs are also detected, they are not involved in the direct electrophysiological effect of NE on IVN neurons. All these results demonstrate that NE directly regulates the activity of IVN neurons via α1 -, α2 -, and β2 -ARs and suggest that the central noradrenergic system may actively participate in IVN-mediated vestibular reflexes and postural control. © 2016 Wiley Periodicals, Inc.

Principles of vestibular pharmacotherapy

Ideally, vestibular pharmacotherapy is intended, through specific and targeted molecular actions, to significantly alleviate vertigo symptoms, to protect or repair the vestibular sensory network under pathologic conditions, and to promote vestibular compensation, with the eventual aim of improving the patient's quality of life. In fact, in order to achieve this aim, considerable progress still needs to be made. The lack of information on the etiology of vestibular disorders and the pharmacologic targets to modulate, as well as the technical challenge of targeting a drug to its effective site are some of the main issues yet to be overcome. In this review, my intention is to provide an account of the therapeutic principles that have shaped current vestibular pharmacotherapy and to further explore crucial questions that must be taken into consideration in order to develop targeted and specific pharmacologic therapies for each type and stage of vestibular disorders.

Comparative Study on the Roles of the Number of Accelerations and Rotation Angle in the Treatment Maneuvers for Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo

AIMS

This study aims to investigate the roles of the number of accelerations and rotation angle in the treatment of posterior semicircular canal benign paroxysmal positional vertigo (PC-BPPV).

METHODS

We enrolled 344 patients with unilateral PC-BPPV. Of these, 167 patients in the simple-step maneuver (SSM) group were accelerated twice and rotated 120° per step, whereas 177 patients in the multi-step maneuver (MSM) group were accelerated 4 times and rotated 60° per step. Dix-Hallpike (DH) tests were performed to categorize the treatment outcome as follows: 'symptom free' if the result was negative, 'symptom persistent' if the result remained positive after performing the maneuver 3 times or 'canal conversion' if horizontal nystagmus was evoked.

RESULTS

Of the patients in the SSM and MSM groups, 78.4 and 91.5% became symptom free, respectively, while canal conversion occurred in 13.8 and 5.1%, respectively (p = 0.003, χ(2) test). The success rate after performing the maneuver once was 57.1% in the MSM and 32.3% in the SSM symptom-free patients (p = 0.001, χ(2) test). One month after the treatment, 22.0 and 9.6% of the SSM and MSM patients had symptom relapse, respectively (p = 0.007, χ(2) test).

CONCLUSIONS

More accelerations and a smaller rotation angle improved the effectiveness and efficiency of the repositioning maneuvers and reduced canal conversion.

Comparative analysis of pharmacological treatments with N-acetyl-DL-leucine (Tanganil) and its two isomers (N-acetyl-L-leucine and N-acetyl-D-leucine) on vestibular compensation: Behavioral investigation in the cat

Head roll tilt, postural imbalance and spontaneous nystagmus are the main static vestibular deficits observed after an acute unilateral vestibular loss (UVL). In the UVL cat model, these deficits are fully compensated over 6 weeks as the result of central vestibular compensation. N-Acetyl-dl-leucine is a drug prescribed in clinical practice for the symptomatic treatment of acute UVL patients. The present study investigated the effects of N-acetyl-dl-leucine on the behavioral recovery after unilateral vestibular neurectomy (UVN) in the cat, and compared the effects of each of its two isomers N-acetyl-L-leucine and N-acetyl-D-leucine. Efficacy of these three drug treatments has been evaluated with respect to a placebo group (UVN+saline water) on the global sensorimotor activity (observation grids), the posture control (support surface measurement), the locomotor balance (maximum performance at the rotating beam test), and the spontaneous vestibular nystagmus (recorded in the light). Whatever the parameters tested, the behavioral recovery was strongly and significantly accelerated under pharmacological treatments with N-acetyl-dl-leucine and N-acetyl-L-leucine. In contrast, the N-acetyl-D-leucine isomer had no effect at all on the behavioral recovery, and animals of this group showed the same recovery profile as those receiving a placebo. It is concluded that the N-acetyl-L-leucine isomer is the active part of the racemate component since it induces a significant acceleration of the vestibular compensation process similar (and even better) to that observed under treatment with the racemate component only.

Influência do tratamento com fármacos antivertiginosos sobre o equilíbrio postural e qualidade de vida de indivíduos com queixas de tontura

Resumo: OBJETIVO: avaliar a influência do tratamento com fármacos antivertiginosos sobre a qualidade de vida e o equilíbrio postural de adultos e idosos com queixas de tontura. MÉTODOS: estudo transversal, com amostra de 51 indivíduos portadores de queixas de tontura, divididos em dois grupos, de acordo com o uso (grupo medicado, n=25) ou não (grupo não medicado, n=26) de fármacos antivertiginosos. Foram coletadas informações sobre: caracterização dos sintomas (ficha elaborada pelos pesquisadores), autopercepção de qualidade de vida (Dizziness Handicap Inventory),intensidade de tontura (escala visual analógica de tontura) e equilíbrio postural (plataforma de força). RESULTADOS: verificou-se intensidade moderada de tontura (Média: 4,6 ± 2,8) e impacto negativo das vestibulopatias sobre a qualidade de vida (Média: 47,3 ± 22,4) na amostra total. Quando comparados os dois grupos, não houve diferença estatisticamente significante na intensidade da tontura (p=0,74) ou qualidade de vida (p=0,79), e também, nos parâmetros da estabilometria, em quatro tarefas (teste t independente, p>0,05). Contudo, após a inclusão do tempo de utilização de fármacos antivertiginosos como uma covariável do estudo, foi verificado pior desempenho nas diferentes tarefas da estabilometria no grupo medicado (ANCOVA, p<0,05). CONCLUSÃO: o uso de fármacos antivertiginosos não melhora a qualidade de vida de indivíduos com queixas de tontura e o equilíbrio postural esteve alterado no grupo medicado.

Na(+) -Ca(2+) Exchanger, Leak K(+) Channel and Hyperpolarization-Activated Cyclic Nucleotide-Gated Channel Comediate the Histamine-Induced Excitation on Rat Inferior Vestibular Nucleus Neurons

AIMS

Antihistaminergic drugs have traditionally been used to treat vestibular disorders in the clinic. As a potential central target for antihistaminergic drugs, the inferior vestibular nucleus (IVN) is the largest subnucleus of the central vestibular nuclear complex and is considered responsible for vestibular-autonomic responses and integration of vestibular, cerebellar, and multisensory signals. However, the role of histamine on the IVN, particularly the underlying mechanisms, is still not clear.

METHODS

Using whole-cell patch-clamp recordings on rat brain slices, histamine-induced effect on IVN neurons and the underlying receptor and ionic mechanisms were investigated.

RESULTS

We found that histamine remarkably depolarized both spontaneous firing neurons and silent neurons in IVN via both histamine H1 and histamine H2 receptors. Furthermore, Na(+) -Ca(2+) exchangers (NCXs) and background leak K(+) channels linked to H1 receptors and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels coupled to H2 receptors comediate the histamine-induced depolarization on IVN neurons.

CONCLUSION

These results demonstrate the multiple ionic mechanisms underlying the excitatory modulation of histamine/central histaminergic system on IVN neurons and the related vestibular reflexes and functions. The findings also suggest potential targets for the treatment of vestibular disorders in the clinic, at the level of ionic channels in central vestibular nuclei.

Danhong enhances recovery from residual dizziness after successful repositioning treatment in patients with benign paroxysmal positional vertigo

OBJECTIVES

Although the repositioning maneuvers are usually very effective in patients with BPPV, some patients still complain residual dizziness. Danhong injection (DHI), a traditional Chinese medicine, can effectively dilate blood vessels and improve microcirculation, and has been proven to be effective in improving cervical vertigo and posterior circulation ischemic vertigo. The aim of this study was to evaluate the effects of DHI on residual dizziness after successful repositioning treatment in patients with BPPV.

METHODS

Eighty-six patients with BPPV were randomized into two treatment groups, DHI group and non DHI group. The DHI group received the same repositioning treatment as the non-DHI group, with the addition of DHI therapy. The durations of residual dizziness of DHI group and non-DHI group were compared. In addition, the scores of the dizziness handicap inventory of these two groups were calculated.

RESULTS

The durations of residual dizziness of DHI group were shorter than that of non-DHI group. There were no significant differences in the scores of dizziness handicap inventory in the first week between these two groups, and there were much significant differences in the second, the fourth, the sixth and eighth weeks.

CONCLUSIONS

The results demonstrate that DHI can significantly improve the residual dizziness after successful repositioning treatment in patients with BPPV.

Postsynaptic mechanisms underlying the excitatory action of histamine on medial vestibular nucleus neurons in rats

BACKGROUND AND PURPOSE

Anti-histaminergic drugs have been widely used in the clinical treatment of vestibular disorders and most studies concentrate on their presynaptic actions. The present study investigated the postsynaptic effect of histamine on medial vestibular nucleus (MVN) neurons and the underlying mechanisms.

EXPERIMENTAL APPROACH

Histamine-induced postsynaptic actions on MVN neurons and the corresponding receptor and ionic mechanisms were detected by whole-cell patch-clamp recordings on rat brain slices. The distribution of postsynaptic histamine H₁, H₂ and H₄ receptors was mapped by double and single immunostaining. Furthermore, the expression of mRNAs for H₁, H₂ and H₄ receptors and for subtypes of Na⁺ -Ca²⁺ exchangers (NCXs) and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels was assessed by quantitative real-time RT-PCR.

KEY RESULTS

A marked postsynaptic excitatory effect, co-mediated by histamine H₁ and H₂ receptors, was involved in the histamine-induced depolarization of MVN neurons. Postsynaptic H₁ and H₂ rather than H₄ receptors were co-localized in the same MVN neurons. NCXs contributed to the inward current mediated by H₁ receptors, whereas HCN channels were responsible for excitation induced by activation of H₂ receptors. Moreover, NCX1 and NCX3 rather than NCX2, and HCN1 rather than HCN2-4 mRNAs, were abundantly expressed in MVN.

CONCLUSION AND IMPLICATIONS

NCXs coupled to H₁ receptors and HCN channels linked to H₂ receptors co-mediate the strong postsynaptic excitatory action of histamine on MVN neurons. These results highlight an active role of postsynaptic mechanisms in the modulation by central histaminergic systems of vestibular functions and suggest potential targets for clinical treatment of vestibular disorders.

Management of benign paroxysmal positional vertigo (BPPV) in the emergency department

Benign paroxysmal positional vertigo (BPPV) is a common medical condition that can be managed by emergency physicians. Vertigo sufferers usually complain of the room spinning associated with certain head movements such as getting out of bed, looking up and bending down. BPPV can be diagnosed clinically from history and examination and does not require any investigations. BPPV can be effectively treated at the bedside by using one of the Canalith repositioning maneuvers (particle repositioning maneuvers). This treatment has been proven to be effective in randomised controlled trials and carries minimal risks. The common complications during the procedure include nausea, vomiting and vertigo. There are no absolute contraindications. BPPV can resolve spontaneously but symptoms may last for weeks in most patients, to years in others. Failure to respond to physical maneuvers and an unusual pattern of nystagmus may suggest a central pathology. Diagnostic strategies and physical manoeuvres are described in this narrative review. Future directions and recommendations also discussed.

Vestibular effects of lidocaine intratympanic injection in rats

When lidocaine is locally delivered into the inner ear, it rapidly paralyzes the peripheral vestibular afferent neurons and induces unilateral vestibular loss. The goals of this study were to explore the possibility of developing intratympanic injection (IT) of lidocaine as a modality for treating acute vertigo. To evaluate the minimum concentration required, latent time, action duration, and possibility of lidocaine IT readministration to the vestibular system, we compared the development of horizontal nystagmus after IT of 2, 4, 6, 8, and 10% lidocaine solutions in rats. To identify the induction of vestibular compensation, c-Fos-like protein expression was observed in the vestibular nucleus. Results of our investigation showed that lidocaine IT concentrations greater than 4% induced vestibular hyporeflexia in the injected ear. In order to induce hyporeflexia 4 and 6% lidocaine solutions could also be repeatedly injected. Regardless of concentration, effects of the lidocaine IT dissipated gradually over time. Our findings could be used to develop novel methods for symptom control in vestibular disorder patients.

Baclofen affects the semicircular canals but not the otoliths in humans

CONCLUSION

This study showed that GABAB agonist baclofen (10 mg) affects the semicircular canals (SCCs), both centrally and peripherally, but does not influence the otolithic function.

OBJECTIVES

The aim of the study was to identify the effects of baclofen on the complete vestibular system, i.e. semicircular canals, saccules and utricles.

METHODS

The study had a double-blind, placebo-controlled, repeated measures design and was conducted on healthy male volunteers. With electronystagmography (ENG), the SCC function was evaluated, whereas utricular function was determined by means of unilateral centrifugation (UC). Cervical vestibular evoked myogenic potentials (cVEMPs) tested saccular integrity.

RESULTS

Baclofen caused a significant increase of the vestibulo-ocular reflex (VOR) phase and a significant decrease of the total caloric response (TCR), both measured during ENG. The drug also decreased the maximal contribution of the SCCs to ocular counter-rolling (OCR) evaluated during UC. No effects on saccules and utricules were observed.

Comparison of the therapeutic efficacy of a fixed low-dose combination of cinnarizine and dimenhydrinate with betahistine in vestibular neuritis: a randomized, double-blind, non-inferiority study

BACKGROUND

Vestibular neuritis (VN) is a strongly disabling disease of the peripheral vestibular system. Rapid and effective relief of symptoms is important to allow patients to promptly return to normal physical activity.

OBJECTIVE

The aim of this prospective, randomized, double-blind study was to evaluate the efficacy of a fixed low-dose combination of cinnarizine and dimenhydrinate in unilateral VN in comparison with betahistine in terms of improvement of vertigo and concomitant symptoms, and performance in neurotological testing.

METHODS

Sixty-two patients were randomized to receive either cinnarizine 20 mg/dimenhydrinate 40 mg as a fixed combination or betahistine 12 mg, each three times daily for 4 weeks. Vertigo and concomitant symptoms, activities of daily living (ADL), posturography and a battery of vestibulo-ocular tests, registered by electronystagmography including spontaneous nystagmus, bithermal caloric and rotatory test, among others, were assessed at baseline (t(0)), after 1 week (t(1w)) and after 4 weeks (t(4w)). The primary endpoint was the Mean Vertigo Score (MVS) at t(1w), a composite of 12 individual scores for unprovoked and provoked vertigo, each assessed using a 10 cm visual analogue scale (VAS). Non-inferiority of the fixed combination versus betahistine would be assumed if the two-sided 95% confidence intervals (CIs) for between-group differences in MVS lay entirely below the non-inferiority margin of 1.25 (12.5% of VAS range).

RESULTS

The fixed combination led to significantly greater improvements in MVS than betahistine both at t(1w) (primary endpoint) and at t(4w) (95% CI for the difference in baseline-adjusted means -0.95, -0.64 at t(1w), -0.77, -0.44 at t(4w); p < 0.001). Vegetative symptoms and ADL also improved significantly more under the fixed combination than under betahistine at t(1w) (p < 0.001, each parameter) and t(4w) (p < 0.001 and p < 0.01, respectively), both showing a nearly complete remission at t(4w). In the two groups, pathological posturography and electronystagmography parameters normalized during the 4-week treatment. The fixed combination group showed an earlier recovery of spontaneous nystagmus than the betahistine group (t(1w), p < 0.001) and slightly higher improvements in asymmetry of rotation-induced nystagmus at t(1w) and t(4w) (p = 0.041, each time point). No significant differences were found between the treatments in abatement of spontaneous nystagmus at t(4w) and decrease of caloric lateralization or improvement of equilibrium (sensory organization test [SOT], conditions 5/6) at t(1w) and t(4w). No patient reported any adverse event.

CONCLUSION

The results showed that the fixed low-dose combination of cinnarizine and dimenhydrinate is an effective and well tolerated option for symptomatic treatment in unilateral VN. The fixed combination led to significant improvements in vertigo and ADL within the first week, and to a nearly complete recovery after 4 weeks. Neurotological testing revealed no signs of a possible detrimental influence of the 4-week treatment with the fixed combination compared with betahistine in terms of recovery of caloric responsiveness and abatement of rotation-induced nystagmus.

Pharmaceutical countermeasures have opposite effects on the utricles and semicircular canals in man

INTRODUCTION

Sensory conflicts in the vestibular system lead to motion sickness of which space motion sickness (SMS) is a special case. SMS affects up to 70% of the astronauts during the first 3 days in space. The search for effective countermeasures has led to several nonpharmacological and pharmacological approaches. The current study focuses on the effects of lorazepam (1 mg), meclizine (25 mg), promethazine (25 mg), and scopolamine (0.4 mg) on the vestibular system, with special focus on the canal and otolith functions separately.

METHODS

The study had a placebo-controlled, single blind, repeated measures design. Sixteen healthy volunteers were subjected to a total of 7 test sessions, the first and last being without intake of medication. Semicircular canal function was evaluated by means of electronystagmography and otolith function with unilateral centrifugation. The horizontal semicircular canal function was characterized by the vestibulo-ocular reflex (VOR) gain measured during earth vertical axis rotation as well as the total caloric response. The function of the utricles was represented by the utricular sensitivity, reflecting the ocular counter roll relative to the virtual induced head tilt.

RESULTS

Promethazine significantly decreased the semicircular canal and utricular parameters. Both scopolamine and lorazepam caused only a decrease in the utricular sensitivity, whereas meclizine only decreased the semicircular canal-induced VOR gain.

DISCUSSION

The results show that the drugs affected different areas of the vestibular system and that the effects can thus be attributed to the specific pharmacological properties of each drug. Meclizine, as an antihistaminergic and weak anticholinergic drug, only affected the VOR gain, suggesting a central action on the medial vestibular nucleus. The same site of action is suggested for the anticholinergic scopolamine since acetylcholine receptors are present and utricular fibers terminate here. The global vestibular suppression caused by promethazine is probably a consequence of its anticholinergic, antihistaminergic, and antidopaminergic properties. Based on the fact that lorazepam increased the affinity of gamma-aminobutyric acid (GABA) for the GABA(A)-receptor and its effects on the utriculi, the site of action seems to be the lateral vestibular nucleus.

CONCLUSION

Meclizine, scopolamine, and lorazepam selectively suppress specific parts of the vestibular system. Selective suppression of different parts of the vestibular system may be more beneficial for alleviating (space) motion sickness than general suppressive agents. Additionally, this knowledge may help the clinician in his therapeutic management of patients with either semicircular canal or otolith dysfunction.

Epley's manoeuvre versus Epley's manoeuvre plus labyrinthine sedative as management of benign paroxysmal positional vertigo: prospective, randomised study

Introduction:

We report a prospective, randomised study of 51 patients with benign paroxysmal positional vertigo treated with Epley's manoeuvre alone or Epley's manoeuvre plus labyrinthine sedative, at Sundaram Medical Foundation, Chennai, India.

Aim:

To compare the efficacy of Epley's manoeuvre versus Epley's manoeuvre plus labyrinthine sedative in the treatment of benign paroxysmal positional vertigo.

Materials and methods:

Consecutive patients were selected based on history and positive Dix–Hallpike test. Patients were randomised to receive either Epley's manoeuvre alone or Epley's manoeuvre plus labyrinthine sedative for one week. Both groups were followed up for four weeks.

Results:

Univariate analysis showed that one- and four-week outcomes were influenced by the number of episodes, symptom duration and treatment type. Multivariate logistic regression analysis showed that the one-week outcome was significantly influenced by symptom duration and treatment type, while the four-week outcome was significantly influenced by symptom duration alone. Patients receiving Epley's manoeuvre alone showed better recovery than those receiving both Epley's manoeuvre and labyrinthine sedative.

Conclusion:

Labyrinthine sedatives do not aid recovery from benign paroxysmal positional vertigo when used in addition to Epley's manoeuvre.