Ground-Level Alternobaric Vertigo: A Contemporary Perspective on Eustachian Tube Dysfunction and Balance

Abstract

This chapter delves into Ground-Level Alternobaric Vertigo (GLAV), with a particular emphasis on its interaction with Eustachian Tube Dysfunction (ETD). GLAV’s prevalence under normal ground-level conditions is gaining attention, highlighting the need for improved understanding and clinical differentiation. Our investigation begins with an examination of GLAV etiology and symptoms before moving on to the evolution of diagnostic and treatment techniques. We track the route from first misdiagnoses to improved comprehension, using sophisticated diagnostics such as tympanometry and encouraging Eustachian tube catheterization. The incorporation of current breakthroughs in GLAV detection and therapy is an important component of this chapter. This includes a full assessment of innovative pharmacological therapies and tactics for managing middle ear cavity pressure, emphasizing the necessity of continuous research for increased diagnostic precision and knowledge of long-term effects. The chapter’s contribution is to advocate for a reevaluation of historical and contemporary vertigo cases for correct diagnosis. It promotes the use of tympanometry in diagnostic protocols and emphasizes the need of joint research in the field of vestibular diseases. This all-encompassing approach makes the chapter an essential resource for healthcare practitioners and academics, matching the dynamic growth of medical knowledge and practices in vestibular sciences.

1. Introduction

1.1 Opening statement

At the core of our discourse on ground-level alternobaric vertigo (GLAV) rests a compelling paradox: a condition that is critical to our comprehension of vestibular disorders (VD) yet often escapes notice in everyday clinical practice (Figure 1). This dichotomy is not merely a gap in scholarly discussion; it is a fundamental deficiency in addressing patient health concerns.

Figure 1.

A Surreal Depiction of Ground-Level Alternobaric Vertigo (GLAV) – This illustration metaphorically represents the dichotomy of GLAV as experienced on Earth versus a distorted gravitational perception akin to another planet. It visually conveys the paradox of a critical yet often clinically overlooked vestibular condition, embodying the dual sensory experiences that define GLAV.

The clinical manifestation of GLAV is obscure, and its symptoms may be erroneously ascribed to more frequently diagnosed conditions such as Meniere’s disease, benign paroxysmal positional vertigo (BPPV) or otolithiasis, vestibular neuritis, vestibular migraine, vertebrogenic dizziness, persistent postural-perceptual dizziness (PPPD), as well as central disorders, and others, if a high level of suspicion is not utilized. This event leads to its frequent misclassification as idiopathic vertigo, highlighting a significant oversight in current diagnostic approaches.

This chapter endeavors to bring GLAV into the spotlight, emphasizing its rightful recognition in the differential diagnosis of VD. Originating from mild Eustachian tube dysfunction (ETD), GLAV presents a diagnostic conundrum. Its proper understanding is essential, not just for academic rigor but, more importantly, for its profound implications in patient care. The unpredictable nature of GLAV symptoms can disrupt daily life activities, leading to a decline in the overall quality of life. A precise diagnosis, therefore, is pivotal for effective treatment strategies, avoiding the pitfalls of misdiagnosis and suboptimal management.

Our goal is to unravel the complexities surrounding GLAV. We aim to shift the clinical focus toward this often-misunderstood condition, enhancing the quality of care for patients grappling with this challenging VD.

1.2 Definition of GLAV

In the realm of VD, GLAV stands out as a unique and often misunderstood entity. It appears as a distinct clinical condition characterized by asymmetric vestibular function due to unequal middle ear pressures (MEP) at ground level [1]. Alternobaric vertigo (ABV) can occur when a pilot’s or diver’s passive opening MEP during an ascent or descent is not the same in both ears at the same height [2]. GLAV often results from minor atmospheric pressure fluctuations worsened by ETD, and it is characterized by vertigo or dizziness that does not involve the dramatic pressure or altitude changes seen in the conventional ABV [3]. GLAV’s hallmark is its occurrence at ground level, highlighting its sensitivity to even small variances in MEP. This condition can significantly disrupt balance and orientation, affecting daily life and underscoring the labyrinthine mechanism’s sensitivity in the inner ear. Understanding GLAV’s unique characteristics is crucial for correct diagnosis and effective management in the realm of VD.

1.3 Brief overview of GLAV

GLAV presents a clinical conundrum, challenging traditional feelings of VD and shedding light on the complex relationship between ET function and vestibular balance. This condition, characterized by vertigo due to subtle variations in MEP, underlines the importance of ET in keeping vestibular equilibrium. GLAV’s sporadic symptoms, often triggered during routine activities, need a nuanced understanding among clinicians for a correct diagnosis and tailored treatment strategies. Recognizing and addressing GLAV in clinical practice can significantly improve the quality of life for those affected, offering relief from the disorder’s disorienting and unsettling impacts.

2. Historical context

2.1 Discussion on Nicolas Deleau’s 1837 report and its implications

The foundation of our historical understanding of GLAV is profoundly anchored in the pioneering work of Nicolas Deleau in 1837 [4]. Deleau’s report, originally perceived in the context of Meniere’s disease [5], is now acknowledged as arguably the earliest clinical description that correlates with what we now know as GLAV. Deleau’s observations were groundbreaking at the time. He described a clinical picture that included dizziness, tinnitus, hearing impairment, a feeling of pressure in the ear, disordered movements of the eyeballs, eye pain, deteriorating vision, and vomiting, which he treated with ETC and an air douche—a technique that improved the symptoms.

Deleau described the experience of Philippine Philippe, a thirty-seven-year-old cook, in one of his cases. She suffered from persistent symptoms such as eye pain from childhood until the age of fourteen, as well as ringing in the ears and eventual deafness, particularly in the left ear, a few years after her menstrual periods began. Her acute symptoms included dizziness, which was unsuccessfully treated with cautery to the arm, and episodes of dizziness followed by vomiting between the ages of twenty-four and twenty-six. Despite general and local bloodletting helped by purgatives, these episodes persisted until June 28, 1836. Deleau’s treatment, which included tube catheterization and air douche over two days, reduced her dizziness and improved her hearing and sight.

This method was pioneering, implying a clear link between ETD and vertiginous symptoms, a concept that was not widely acknowledged or understood at the time [4, 5]. The importance of Deleau’s study resides in its unintended revelation of GLAV decades before the name or idea was publicly recognized. His study alluded to the relevance of the ET in sustaining not only auditory function but also balance. This early link between ETD and vertigo calls into question the later, more narrow focus on the vestibular system alone in explaining vertiginous symptoms.

Incorrectly reading Deleau’s observations as Meniere’s disease rather than GLAV reflects the historical pattern of misunderstanding and undervaluing the importance of GLAV in vertigo, particularly in practical contexts. This occurrence exemplifies a broader tendency in the field of medical history, in which innovative understandings frequently remain hidden in incorrectly understood data, awaiting reevaluation and right categorization. Deleau’s observations have substantial ramifications in modern therapeutic practice. They serve as a reminder of the complexities of vertigo and VD and the importance of recognizing ETD as a main factor in the differential diagnosis of vertigo. His report recommends for a more holistic approach to detecting and treating vertigo, one that acknowledges the ET’s function in vestibular health. Deleau’s work thus not only contributes to the historical narrative of GLAV but also conveys important lessons for modern medicine: the need of holistic assessment in VD and the possibility for historical medical reports to inform and enhance present understanding and practice.

2.2 Evolution of understanding in the field

A rich history of understanding and scientific advancements surrounds GLAV and its relationship with ETD. This subsection explores the journey from early recognition to contemporary perspectives, highlighting how our comprehension of GLAV and ETD has transformed over the years.

2.2.1 Early observations and theories

There has been a gradual and significant evolution of understanding on the road to understanding GLAV in the fields of otolaryngology and vestibular medicine. Since the early observations of Nicolas Deleau in 1837, our comprehension of GLAV and its relationship with ETD has undergone a transformative journey, shaping the modern approach to VD. In the years following Deleau’s report, the focus in vestibular medicine was primarily on the inner ear mechanisms, with a limited appreciation for the role of the ET. Common VDs such as Meniere disease and BPPV dominated clinical attention, while the subtleties of GLAV remained largely unrecognized.

2.2.2 Adam Politzer’s contribution to ETC

A significant figure in the mid-nineteenth-century otology, Adam Politzer, performed critical studies on the ear’s nerve supply and the pressure effects of the tympanic cavity on the labyrinth in 1861 [6]. Simultaneously, he conducted extensive microscopic inspections of the labyrinth, fostering professional relationships that advanced otological knowledge. These investigations contributed to a better understanding of auditory mechanics and balance. Politzer’s ideas extended beyond theoretical studies to practical applications, most notably his invention of the eponymous Politzerization in 1863. This method was designed to ensure the functionality of the ET, providing a less invasive alternative to the then-common ETC. Politzer’s method permitted non-invasive middle ear inflation by injecting a puff of air into the patient’s nostril while swallowing, simplifying the process of balancing middle ear and nasopharyngeal pressures, and furthering the treatment of ETD [7].

Politzer’s passion for improving ETC procedures was clear throughout his tenure. His ongoing clinical trials and collaborations, particularly with Josef Gruber, have significantly advanced the treatment of ETD. Despite Gruber’s proposal of the term “Valsalva’s passive experiment” in 1870 as an alternative to “Politzer’s method,” which Gruber did not favor, Politzer’s techniques eventually gained wider recognition. Gruber’s contributions, while valuable, notably his version of the insufflation airbag, did not achieve the long-term reputation that Politzer’s methods earned [8]. To summarize, Adam Politzer’s contributions to ETC were critical in defining the present approach to vestibular medicine. His study not only gave a deeper understanding of the physiology of the ear, but it also revolutionized the practical treatment of diseases connected to the ET, creating a new standard in the field.

2.2.3 James Yearsley’s perspective on systemic influences on ear health

James Yearsley’s work “Deafness Practically Illustrated,” published in 1863, introduced the new concept of “stomach deafness,” in which he linked gastrointestinal issues to the functioning of the ET [9]. Yearsley postulated that disorders such as gastroesophageal reflux (GERD), laryngopharyngeal reflux (LPR), and nasopharyngeal reflux (NPR) could have a major impact on auditory health. Recent research has backed up this theory by finding a relationship between systemic health and otolaryngological problems. His understanding of the multifaceted character of ETD includes what is now recognized as reflux-related inflammation, broadening the etiological spectrum of ear disorders [9].

2.2.4 Peter Allen’s progressive insights and the onset of modern otolaryngology

Peter Allen is remembered in the history of otolaryngology for his fundamental work in 1871, which represented a critical turn toward contemporary study in the profession. Allen provided unique insights into the specific situation of VD, building on the fundamental work of forefathers such as Adam Politzer, who established the impact of tympanic cavity pressure on the labyrinth. His talks, particularly on “Aural Catarrh,” shed light on the complexity of ETD and its profound consequences for vertigo. Allen’s work into the intricacies of intra-auricular pressure—notably its impact on labyrinth fluid—was a game changer, showing the direct influence of these pressure changes on vestibular symptoms. This trailblazing viewpoint was crucial in creating modern knowledge of VD, establishing such pressure fluctuations as a cornerstone notion in current otolaryngological practice [10].

Allen bridged the gap between the historical insights supplied by a pioneer like James Yearsley and the then-nascent modern techniques by focusing on the significance of intratympanic and intralabyrinthine pressures in the field of vertigo. His contributions were more than incremental; they were a quantum leap in the science of otolaryngology, foreshadowing principles that remain basic in the assessment and treatment of ear-related balance problems. In this sense, Peter Allen’s legacy goes beyond that of a historical figure. He is regarded as a visionary whose intellectual daring created the groundwork for future otological inquiry and invention. Many sophisticated practices that are important to modern otolaryngological care were foreshadowed by his thoughts on the inner workings of the ear, particularly the importance of ET in vestibular health. Allen’s commitment to increasing medical understanding and practice has been critical in setting the way for a richer, more educated engagement with vestibular health issues [10].

2.3 Twentieth century: a focus on ET obstruction

The twentieth century witnessed a growing interest in the complexities of the vestibular system, with advancements in diagnostic technologies and a deeper understanding of vestibular pathophysiology. However, the connection between ETD and vertigo, particularly at ground level, remained underexplored. GLAV, with its elusive and often non-specific symptoms, continued to be overshadowed by more prominent vestibular conditions.

In 1942, F.W. Merica supplied more elucidation by characterizing vertigo as a manifestation of ET obstruction during the mid-twentieth century. This distinction marked a significant moment, linking historical data with a rising awareness of how dysregulated MEP could lead to VD, thus laying the groundwork for the contemporary diagnosis of GLAV [11].

The trajectory of the GLAV story underwent a notable shift following the introduction of the term “alternobaric vertigo” by Dr. Claes Lundgren in 1965. Lundgren’s research initially focused on the manifestation of symptoms in divers and aviators resulting from significant fluctuations in barometric pressure [3, 12]. In the historical exploration of VD, particularly ABV, a significant development is the understanding of its occurrence in pilots. ABV in pilots is a specific manifestation of VD that arises from unequal MEP during ascent. Notably, ABV can occur when a pilot’s passive opening of MEP is not symmetrical in both ears at the same altitude [2, 12]. This phenomenon has been pivotal in shaping our understanding of ABV, as it highlights the crucial role of ET function in keeping vestibular balance, especially under changing atmospheric conditions. This understanding has not only advanced the field of otolaryngology but also has significant implications for the safety and well-being of pilots and other individuals exposed to similar conditions. This work set up a precedent for finding comparable vestibular reactions arising from the less pronounced pressure changes met at ground level.

It was not until the late twentieth and early twenty-first centuries that a more holistic view began to emerge, integrating the role of the ET in the diagnosis and treatment of vertigo. This shift was driven by a combination of factors: an increase in clinical research, improved diagnostic techniques like the several kinds of vestibular function tests (VFT), and a growing recognition of the limitations of existing approaches to addressing all forms of vertigo.

2.4 The modern era: the emergence of GLAV

The contemporary knowledge of GLAV owes largely to Dr. Bluestone’s seminal study. His research revealed the chronic Toynbee phenomenon, which causes persistent swallowing while suffering from nasal congestion, and its link to GLAV. Notably, his research shed light on the treatment of ETD and accompanying symptoms, implying the possible benefits of ETC.

Several major discoveries emerged from Dr. Bluestone’s research:

The relationship between persistent ABV at ground level and abnormal VFT results.

It has been established that restoring bilateral MEP can improve vestibular function and alleviate vertigo symptoms.

The realization is that tympanostomy tubes do not always restore normal ET function.

Dr. Bluestone’s demand for comprehensive ET function testing emphasized the fact that ETD is a spectrum condition with a wide range of causes and manifestations. His efforts have advanced our understanding of GLAV and affected the larger approach to ETD treatment, emphasizing the relevance of ET function in the diagnosis and management of vestibular disorders [1].

2.5 Looking back and moving forward: advances in research and treatment

In the evolving narrative of GLAV, a crucial turning point has been the reevaluation of historical cases, including Deleau’s report. This reexamination, primarily driven by a few researchers, including myself, has brought new insights into the significance of ETD in vertigo. This shift in perspective has contributed to a more sophisticated understanding of GLAV, positioning it not merely as a VD but as a condition significantly influenced by the functionality of the ET. An appreciation for the intricate interaction between the ET and the vestibular system today marks the understanding of GLAV. This recognition has paved the way for more comprehensive diagnostic approaches and targeted treatment strategies, moving beyond the conventional focus on the inner ear alone.

The evolution of understanding in the field of VD, particularly regarding GLAV, illustrates the dynamic nature of medical knowledge. It highlights the importance of continual reevaluation and integration of historical insights with contemporary research, ensuring a holistic and informed approach to patient care. The existing comprehension of GLAV is built upon a diverse range of intellectual curiosity and scientific investigation. Each of these researchers, from Deleau to Bluestone, offered crucial insights, effectively bridging centuries of medical thought, and defining a trajectory that has revolutionized the approach to ETD and balance problems. Their legacies live on in every modern treatment protocol for GLAV, a lasting tribute to the enduring force of medical development.

3. Etiology and pathophysiology

Understanding the etiology and pathophysiology of VD, particularly those related to ETD, is essential for correct diagnosis and effective treatment. This section incorporates key insights from notable studies, supplying a comprehensive overview. Evaluating the ET’s functionality is the first essential step in realizing that ETD is a complex spectrum of disorders. It is not just about the tube being overly tight or excessively open. This spectrum includes a variety of conditions, each with its own distinct causes and implications for health [13]. Alernobaric Vertigo (ABV), a VD associated with ETD in pilots or divers, often occurs because of unsynchronized MEP opening in both ears during ascent, resulting in symptoms such as vertigo [12]. Tjernström’s study underlines the significance of pilots maintaining balanced MEP [2].

3.1 Mechanisms leading to ETD

ETD is caused by a mix of variables and triggers and can range in severity from little disorientation to intense, devastating episodes. Among the mechanisms that contribute to ETD are:

Certain anatomical variations can interfere with ET function. Among these are nasopharyngeal carcinoma, a cancer of the upper throat, and tumors of the middle cranial fossa. Conditions such as infections or allergies can cause transient or chronic ETD. GERD, LPR, and NPR can all produce inflammation and contribute to ETD. Sudden variations in air pressure, such as those experienced during flights, diving, elevating, or weather events, might put the ET’s ability to control MEP to the test, potentially resulting in GLAV. Variations in barometric pressure can worsen ETD even at ground level. Factors such as allergic reactions, sinus infections, and common colds can cause inflammation and congestion, restricting ET function. Furthermore, habits such as sniffing, heavy lifting, formidable Valsalva maneuvers, or drinking water before lying down can aggravate ETD and cause GLAV episodes [14, 15, 16].

It is critical to distinguish between “Eustachian tube dysfunction” and “Eustachian tube obstruction.” While obstruction refers to physical blockages, ETD comprises a broader range of both obstructive and functional problems. Understanding this distinction is crucial for guiding suitable treatment techniques and grasping the full range of ET-related disorders [16].

3.2 Impact on middle ear and vestibular system

ETD leads to imbalances in MEP, affecting the vestibular and auditory systems. This can result in dizziness, balance issues, and auditory disturbances. Both positive and negative pressure scenarios, akin to ascending or descending in altitude, disrupt hearing and balance mechanics. In cases of GLAV, the ETD-induced pressure imbalance in the middle ear causes abnormal stimulation of the vestibular system. The unequal pressures on either side of the tympanic membrane can create a distorted transmission of sound waves, leading to the vestibular symptoms of GLAV, such as dizziness and balance issues [1, 12, 17, 18].

3.2.1 Positive MEP state at ground level (similar to ascending state)

When the ET becomes obstructed in cases of positive MEP, like that experienced by divers or aviators, a unique challenge arises. Because there is insufficient positive pressure in the middle ear to force the tube open, this obstruction prevents the equalization of even minor positive pressures within the middle ear. Mechanical and hydraulic disturbances in the cochlea and vestibular organs can result from the resulting imbalance. The strain on the tympanic membrane and ossicular chain caused by this unabated positive pressure can impair sound transmission and cause dysregulation and symptoms like aural fullness, tinnitus, and hearing loss. This condition can mimic barotrauma and aggravate GLAV symptoms, especially if the ET still is obstructed, preventing pressure relief [12, 17, 18].

3.2.2 Negative MEP at ground level (similar to descending state)

Negative MEP, typically experienced during descent, can manifest at ground level due to ETD. This leads to a failure to equalize the increasing ambient pressure, creating a vacuum effect in the middle ear. The inward retraction of the tympanic membrane disrupts the ossicular chain and inner ear window dynamics. This results in abnormal fluid movements within the labyrinth, causing the disorienting symptoms of vertigo and the imbalance characteristic of GLAV [12, 17, 18].

3.3 Pathophysiological outcomes and long-term effects of ETD

The major effect of ETD is a disruption in pressure regulation in the middle ear, which results in vestibular disturbances such as vertigo. This dysfunction can progress to middle ear barotrauma and harm the vestibular nerve, resulting in impaired balance and spatial orientation. Chronic ETD may result in fluid buildup in the middle ear, exacerbating vestibular symptoms.

Long-term symptoms of GLAV because of ETD include persistent vertigo, dizziness, and gastrointestinal disease which can considerably affect everyday activities [1, 11]. Prolonged pressure imbalances can cause hearing loss and tinnitus. The persistence of these symptoms can cause psychological stress, such as anxiety and depression, as well as cognitive challenges such as concentration and recall issues [1, 19]. Balance issues increase the risk of falls and injuries, especially in older persons. GLAV can also have an impact on social relationships and occupational performance, demanding a complete approach to ETD diagnosis and care to promote overall patient well-being.

4. Clinical presentation

4.1 Symptoms and signs

ETD typically presents a variety of symptoms, commonly acknowledged by otolaryngologists as muffled hearing, ear pain, tinnitus, decreased hearing, a sensation of fullness in the ears, and balance issues [14, 15]. However, GLAV, strongly associated with ETD, manifests a broader spectrum of symptoms that extend beyond the auditory system. These encompass gastrointestinal [11, 17, 20], autonomic [21, 22], and psychopathological aspects [19], including:

1. Ear-related Symptoms: Common symptoms include ear fullness or pressure, tinnitus, ear pain or headache, popping or clicking sensations, dizziness or balance problems, and ear itching.

2. General Health and Well-Being: Changes in sleep quality, appetite variations, fluctuations in energy levels, stress, and anxiety. Anxiety in GLAV patients specifically can stem from the fear of vertigo episodes, balance issues, and the unpredictability of symptoms.

3. Gastrointestinal Disturbances and Laryngopharyngeal Reflux: Nausea, vomiting, globus sensation (feeling of a lump in the throat), and hoarseness, which can be a symptom of laryngopharyngeal reflux, potentially secondary to ETD.

4. Autonomic Responses: Bradycardia (slow heart rate), respiratory difficulties, sweating episodes, and blood pressure changes.

5. Psychopathological Aspects: Heightened anxiety due to vestibular dysfunction, fear of falling or losing balance, avoidance behaviors, and the feedback loop between anxiety and vestibular symptoms.

6. Cognitive and Behavioral Mechanisms: Disorientation, postural instability, attentional and cognitive load issues influencing balance and orientation perception.

4.2 Diagnosis

Recognizing the extensive and varied symptoms associated with GLAV and ETD is essential for correct diagnosis and effective management, emphasizing the need for an integrated approach to patient care. The diagnostic process typically begins with otoscopy, tympanometry, and nasal endoscopy in a secondary care setting to evaluate the ear and nasopharyngeal areas [15].

5. Diagnostic criteria and methods for GLAV

Diagnosing GLAV needs a multidisciplinary approach, focusing on ETD and its impact on vestibular functions. The key goal in diagnostics is achieving balanced MEPs, ideally “0 daPa and 0 daPa,” to accurately assess the vestibular symptoms specific to GLAV.

5.1 Clinical assessment

A comprehensive clinical assessment is required to diagnose and manage GLAV. This evaluation consists of the following components:

1. Medical History review: A comprehensive assessment of the patient’s medical history is performed, with emphasis on the onset, duration, and particular characteristics of vertigo and any accompanying symptoms. This includes looking into any ear infections, surgeries, or Ear, Nose, and Throat (ENT) issues in the past. The assessment also considers the patient’s exposure to environmental factors that may impact ear pressure.

2. The physical examination: Otoscopy is used to check for any abnormalities in the ear canal and tympanic membrane. Nasopharyngoscopy is used to evaluate the opening of the ET and look for evidence of NPR. Laryngoscopy is used to detect LPR. A neurological examination, with a special emphasis on the vestibulocochlear nerve, is required to determine whether the patient’s symptoms are caused by a neurological condition.

5.2 Diagnostic testing

5.2.1 PTA

PTA is an essential diagnostic method for assessing hearing levels, especially in situations of GLAV. The study focuses on both low- and high-frequency hearing losses, with each providing distinct diagnostic insights:

1. Low-Frequency Hearing Loss: This is an indication of ETD, in which negative MEP leads to tympanic membrane retraction. Such retraction alters the ear’s response to low-frequency sounds, indicating the presence of ETD.

2. High-Frequency Hearing Loss: Although rare, high-frequency hearing loss can indicate more chronic or severe ETD. This could be related to problems such as middle ear effusion, which hinders high-frequency sound transmission.

3. Clinical Implications in GLAV: It is crucial to identify these specific patterns of hearing loss when diagnosing ETD in the context of GLAV. Understanding the type and extent of hearing loss not only helps to confirm the ETD diagnosis, but it also helps to understand how ETD affects vestibular symptoms. This information is critical for building an effective treatment plan that is tailored to the needs of the person who is receiving treatment.

5.2.2 Tympanometry

Traditional tympanogram categories (A, Ad, As, B, and C) are insufficient for GLAV diagnosis. They need a more refined interpretation to detect minor ETD relevant to GLAV. Any variation from the “0 daPa and 0 daPa” norm suggests ETD, a significant part in GLAV, needing careful tympanometry investigation.

To summarize, tympanometry for GLAV necessitates a move from standard classifications and “within normal limits” to a focused examination on setting up balanced MEPs, ensuring exact diagnosis and effective GLAV care.

5.2.3 VFTs

Caloric Testing, Vestibular Evoked Myogenic Potentials (VEMP), Posturography, Videonystagmography (VNG), Rotational Chair Testing, Head Impulse Test (HIT), and Computerized Dynamic Posturography (CDP) are important VFTs for diagnosing GLAV and developing treatment options. Accurate test results require balanced MEPs.

1. Caloric Testing: Asymmetric MEPs can interfere with thermal stimuli conduction, potentially leading to false signs of unilateral vestibular weakness.

2. VEMP: Changes in MEP can affect sound transmission and thus test results.

3. Rotary Chair Test: While less directly influenced, considerable pressure changes can alter motion perception and results in the rotary chair test.

4. Electronystagmography (ENG) /Videonystagmography (VNG): Asymmetric MEPs can similarly affect the outcomes of these components.

5. HIT and CDP: Variations in MEP can have a direct impact on the results of the HIT and CDP, potentially changing balance and vestibular response evaluations due to MEP imbalances.

Given the dynamic nature of MEP, which is influenced by factors such as ET function and respiratory circumstances, getting a precise 0 daPa of MEP for VFTs can be difficult. In such cases, ETC is a useful technique. ETC provides a more direct method of managing and controlling MEP, potentially allowing for a closer approach to the ideal 0 daPa aim. This strategy is especially useful in situations when standard treatments fail, such as when there are considerable variations in MEP or ETD. ETC can thus improve VFT precision by ensuring that MEP is set as precisely as feasible to optimize test accuracy [14, 18].

5.3 Patient reported outcome measures (PROMs)

Utilizing PROMs that cover a wide array of symptoms, including those related to gastrointestinal [11, 17, 20], autonomic [21, 22], and psychopathological symptoms [19], can supply a deeper insight into the patient’s condition.

5.4 ET function examination

Dr. Charles Bluestone’s groundbreaking research emphasized the importance of ET function tests in diagnosing GLAV, particularly in patients with symptoms of ETD such as vertigo despite an intact tympanic membrane and no otitis media [12].

Based on personal insights, ET function testing with ETC and Toynbee diagnostic tube is advised even when PTA and impedance audiometry (IA) show normal results [14, 18]. Beyond the insights provided by Bluestone, this technique aids in thoroughly tackling the complexities of GLAV.

In GLAV instances, the incorporation of expanded testing ensures a thorough assessment for probable underlying ETD, leading to more correct diagnoses and effective treatment solutions.

The field of otolaryngology is evolving, with increased testing procedures reflecting a stronger understanding of GLAV and ETD. Bluestone’s contributions continue to be a cornerstone of this continuing research, which is critical to improving patient care.

5.5 Imaging studies

Supportive tools like CT scans and MRIs are used to rule out other causes of vestibular symptoms that might mimic GLAV.

5.6 Reflux assessment

In the diagnostic process for GLAV, assessing reflux-related contributions to ETD is a crucial aspect. This involves two primary methods: pH monitoring and laryngoscopy. Both pH monitoring and laryngoscopy are vital for deciding whether reflux plays a role in a patient’s ETD and consequent GLAV symptoms. Finding and treating underlying reflux conditions can be a key part in the effective management of GLAV, as controlling reflux may alleviate some of the ETD symptoms and improve overall ear and vestibular health [20].

5.7 Diagnostic criteria

The diagnosis of GLAV is based on criteria that link vestibular symptoms with ETD, with the primary goal of attaining a “0 daPa and 0 daPa” balanced MEP in both ears. This balance is critical for correctly diagnosing GLAV because it helps to rule out other potential causes of vestibular symptoms that are not related to ETD, assuring that the symptoms are caused by ETD-related difficulties.

1. Vestibular Symptom Evaluation: Initially, dizziness is assessed with a focus on diagnosing GLAV, with particular attention paid to symptoms at ground level and environmental pressure fluctuations.

2. ETD Evaluation: The presence of ETD, characterized by unequal MEP, is critical in the diagnosis of GLAV. To determine pressure balance, ETC is recommended.

3. Equilibrium of MEP: The achievement of “0 daPa and 0 daPa” in both ears is critical for GLAV diagnosis, distinguishing ETD-related symptoms from other VD. The importance of tympanometry in validating this balanced state cannot be overstated.

5.8 Differential diagnosis

The differential diagnosis of GLAV requires a multifaceted approach, incorporating assessments like alongside balanced MEP evaluation, laryngoscopy, nasopharyngoscopy, and the application of specialized PROMs. This comprehensive method is crucial for accurately distinguishing GLAV from other VD.

Balanced MEP Evaluation: Setting up equilibrium in MEP at “0 daPa and 0 daPa” is critical for differentiating GLAV from other vestibular conditions. This involves tympanometry and ET function tests to find the absence of ETD-related factors contributing to vestibular symptoms.

1. Nasopharyngoscopy: This diagnostic procedure examines the nasopharyngeal area and the ET opening. It is essential for finding structural or inflammatory issues that might mimic or contribute to vestibular symptoms, aiding in differentiating GLAV from other conditions.

2. Laryngoscopy: Given the reciprocal relationship between ETD and LPR, laryngoscopy is a vital part of the differential diagnosis. It helps in finding LPR, which can worsen or mimic symptoms of ETD and thus influence the presentation of GLAV [23].

3. Application of New PROMs or ePROMs: The use of newly developed PROMs, specifically designed for GLAV and ETD, is integral. These tools capture a broad spectrum of symptoms beyond the typical vestibular ones, for the exact diagnosis ETD. This wider symptom capture enables a more correct differentiation of GLAV from other vestibular disorders.

6. Management and treatment of GLAV

Understanding the reciprocal causal link between ETD and LPR is essential for effectively treating GLAV. GLAV, which causes vertigo owing to MEP imbalances, is frequently associated with these disorders. Normalization of MEP is critical in breaking the reciprocal cycle between ETD and LPR in GLAV management. In this scenario, ETC is important. ETC can help attenuate the influence of LPR on ET by directly intervening to rectify ETD, hence decreasing GLAV symptoms. In this therapy paradigm, effective LPR management through food, lifestyle changes, and medication is critical. Controlling LPR helps to lessen its aggravating effect on ETD, which aids in the management of GLAV symptoms [18, 20].

To reduce inflammation and improve ET function, pharmacological therapies such as decongestants, antihistamines, vasoconstrictors, mucolytics, antibiotics, and steroids are used. These medications address the ETD component of the cycle, hence influencing the effects of LPR indirectly [15].

Another method used in this comprehensive therapeutic strategy is balloon tuboplasty. It focuses on removing physical obstructions from the ET. The Valsalva technique, contrary to popular belief, is not indicated in postoperative care due to its potential dangers. Alternative procedures like ETC are recommended to ensure patient safety while retaining the procedure’s efficacy [14].

If balance problems persist, vestibular rehabilitation is advised, pending normalization of middle ear pressures. This technique is designed to correct balance issues without exacerbating vertigo symptoms.

This therapeutic technique prioritizes patient education and support. Understanding GLAV, ETD, and LPR, as well as their interconnections, enables patients to engage in successful self-management strategies. In conclusion, GLAV management and treatment require a comprehensive approach that acknowledges and treats the reciprocal interaction between ETD and LPR. ETC, pharmaceutical therapies, balloon tuboplasty, and a comprehensive approach to LPR management all help to interrupt this complex loop and provide relief from GLAV symptoms [20].

7. Case studies and clinical evidence of GLAV

7.1 Illustrative case studies

7.1.1 Case study 1: chronic GLAV in a middle-aged adult: Meniere disease

Background: A 45-year-old female patient, a few years ago, experienced intermittent ear fullness and tinnitus, frequent coughing and chronic vertigo episodes. Initially misdiagnosed with Meniere’s disease, surgery was suggested in a university hospital. She had nausea and prolonged tinnitus after intratympanic steroid injections. By the last year, the patient’s gastrointestinal problems had worsened, and symptoms had spread to include stomach pain, flank pain, urine discomfort, and reflux esophagitis. The patient’s habit of sniffing is indicative of chronic GLAV.

Clinical Assessment: During the initial clinic visit on December 2023, tympanometric measurements revealed severe negative pressures of −250 daPa in left ear and −7 aPa in the right, indicating ETD. This asymmetry in MEPs was suspected to be the source of the vestibular symptoms. Hearing difficulty and tinnitus were confirmed by audiometric tests, while gastroenterological investigations indicated gallstones and reflux esophagitis.

Intervention: ETC was used to manage the ETD due to the complex symptom profile and tympanometric results. Concurrently, the patient’s gastrointestinal issues were treated.

Outcome: Post-catheterization, the patient reported significant alleviation of vertigo, confirmed by balanced middle ear pressures in follow-up tympanometry. Tinnitus was reduced, and episodes of ear fullness were eliminated. Additionally, the tailored therapy alleviated gastrointestinal problems. The patient currently reports no problems, indicating the ETC’s efficacy in controlling the patient’s illness.

This example demonstrates the efficacy of ETC in the treatment of GLAV, especially in complex patients with many symptoms and considerable asymmetric negative middle ear pressures. It emphasizes the significance of a thorough clinical evaluation and a multidisciplinary approach to treatment.

7.1.2 Case study 2: acute GLAV episode in a young adult: Otolithiasis

Background: A 30-year-old male, previously diagnosed with otolithiasis, experienced sudden dizziness and balance issues after a workout. Regularly drinking water before lying down, the patient was recommended to perform an Epley’s maneuver technique by another otolaryngologist.

Clinical Assessment: Otoscopic examination was normal, but tympanometry revealed a notable MEP differential with negative pressures of −73 daPa in the left ear and −45 daPa in the right, indicating ETD.

Intervention: Following ineffective nasal decongestant use, ETC was successfully administered.

Outcome: Immediate symptom relief was noted post-procedure, with maintained ear pressure balance and no recurring vertigo in later follow-ups.

7.1.3 Case study 3: recurrent GLAV in an elderly person

Background: A 65-year-old male with a history of recurrent vertigo episodes that were initially misdiagnosed as age-related vestibular deterioration. The patient described episodes in response to weather changes and trouble adjusting to elevation variations when traveling.

Clinical Evaluation: Audiometric testing revealed a modest high-frequency hearing loss. Tympanometry revealed a negative −43 daPa MEP in the left ear and 0 daPa in the right eat, indicating ETD. Vestibular function tests found minor irregularities.

Intervention: A combination of ETC and vestibular rehabilitation activities, as well as dietary changes for mild LPR, were commenced.

Outcome: The patient reported a significant decrease in vertigo frequency and intensity, as well as improved tympanometry readings, indicating efficient ETD therapy.

7.1.4 Case study 4: GLAV in a teenager with allergic rhinitis

Background: A 17-year-old female with allergic rhinitis presented with episodes of dizziness and instability, particularly during allergy season. Initially unsuccessfully treated for benign paroxysmal positional vertigo (BPPV).

Clinical Assessment: Allergy testing revealed considerable nasal congestion. Tympanometry revealed a flat B type without middle ear effusion with unmeasurable MEP in the right ear and a positive 111 daPa MEP in the left ear, whereas VFTs were inconclusive due to changing results.

Intervention: Treatment included nasal steroids for allergic rhinitis and ETC sessions for ETD. Vestibular rehabilitation was postponed until MEP normalization.

Outcome: After several weeks, the patient reported a considerable decrease in vertigo occurrences, which correlated with improved tympanometric readings and reduced nasal symptoms.

7.2 Introduction of the article

A Case Report on Ground-Level Alternobaric Vertigo Due to Eustachian Tube Dysfunction with the Assistance of Conversational Generative Pre-Trained Transformer (ChatGPT) [24]

Kim H (March 28, 2023) A Case Report on Ground-Level Alternobaric Vertigo Due to Eustachian Tube Dysfunction with the Assistance of Conversational Generative Pre-Trained Transformer (ChatGPT). Cureus 15(3): e36830. doi:10.7759/cureus.36830

This Dr. Hee-Young Kim’s article supplies a comprehensive study on GLAV due to ETD, underscoring the necessity of correct diagnosis and effective interventions, such as ETC [24].

7.3 Additional reference

7.3.1 “Alternobaric vertigo: asymmetrical vestibular function due to asymmetrical middle ear pressures (Iron Man’s Archenemy)”

Kim HY. Alternobaric vertigo: Asymmetrical vestibular function due to asymmetrical middle ear pressures (Iron Man’s archenemy). [Internet]. ENT & Audiology News. Pinpoint Scotland Ltd; 2021 [cited 2023 Dec 13]. Available from: https://cloud.3dissue.net/30176/30070/30342/63730/index.html?page=42.

In this article, Dr. Hee-Young Kim discusses ABV, a result of asymmetrical vestibular function due to unequal middle ear pressures, emphasizing the importance of recognizing and managing ETD to effectively treat ABV. The article advocates for ETC as a crucial diagnostic and therapeutic tool in such cases [13].

7.3.2 “Eustachian tube catheterization: fundamental skill for competent otolaryngologists”

Kim HY. Eustachian tube catheterization: fundamental skill for competent otolaryngologists. Journal of Otolaryngology ENT Research. 2019;11(1):15–17. DOI: 10.15406/joentr.2019.11.00401

Dr. Hee-Young Kim’s document highlights the critical role of ETC in diagnosing and treating ETD. The article delves into common symptoms, the technique of ETC, its diagnostic and therapeutic values, and the association between LPR/GERD and ETD, advocating ETC as an essential skill for otolaryngologists in managing ETD-related symptoms [18].

8. Modern perspectives and advances

This section examines recent advances in GLAV research and therapy, focusing on the integration of technology and patient-centered approaches.

8.1 The emerging role of biomarkers in GLAV diagnosis and management

In recent years, the possibility of identifying accurate biomarkers has opened up new paths in the diagnosis and treatment of GLAV. Biomarkers hold the promise of providing more objective, quantifiable measurements of disease prevalence and severity, potentially leading to earlier detection and more customized treatment regimens. While research on specific GLAV biomarkers is ongoing, the incorporation of such diagnostics offers significant promise for increasing our understanding of the condition and patient care. The identification and validation of these biomarkers such as middle ear pressure may alter the clinical approach to managing ETD and its related GLAV as the science progresses.

8.2 Mobile eye movement recording technology in vertigo diagnosis

Mobile eye movement recording technology, which enables real-time data capture during vertigo episodes, is a recent breakthrough. This approach is compatible with the recommendation for first ET function tests, resulting in more accurate diagnosis and aligning with modern diagnostic practices. Although the ET function test findings are unknown prior to the mobile eye movement recording test, data on eye movements during vertigo can be collected.

8.3 Development of new PROMs for ETD

A new PROMs instrument is being developed to evaluate the outcomes of ETC and other ETD therapies. The instrument intends to cover a wide variety of ETD symptoms, including gastrointestinal, autonomic, and psychopathological features, to improve the evaluation of treatment efficacy and patient quality of life [25]. The advancement entails: 1. Question formulation and refinement based on patient and expert feedback. 2. First clinical testing and evaluation of reliability and validity. Once completed, this PROM will be used in clinical practice for ETC patients and will be updated on a regular basis to reflect new findings and patient experiences. This technology will be crucial in improving ETD therapy and patient care.

8.4 electronic patient-reported outcome measures (ePROMs): a digital health initiative for ETD

The ePROMs program solves ETD’s diagnostic shortcomings. It proposes a web-based tool for ETD management, with the goal of increasing patient interaction and standardizing outcome measurement. The effort forms smartphone apps and wearable devices for symptom monitoring, emphasizing the importance of digital health technology in ETD care.

These advances in GLAV diagnosis and treatment represent a move toward more precise, patient-centered approaches that incorporate technological improvements to improve care quality and patient outcomes [26].

9. Challenges and controversies

9.1 Current diagnosis and treatment obstacles

Diagnosis of GLAV poses special problems, particularly in emergency and outpatient settings. In emergency rooms, evaluating MEP is often disregarded, resulting in missed GLAV diagnoses. Delayed consultations following acute symptoms in outpatient clinics might make diagnosis GLAV challenging, as vestibular abnormalities may not be present during examination. An ideal diagnosis method would include testing as soon as symptoms appear.

9.2 Controversial issues and diverging points of view

Several disputed concerns continue in the study of GLAV. The pathogenesis remains unclear specifically how ETD causes GLAV and how it interacts with laryngopharyngeal reflux. Medical practitioners have yet to agree on MEP thresholds and the use of audiometry and tympanometry in diagnosing the condition. The methods of treatment are also contentious, with little agreement on the most effective interventions, including the importance of ETC. Managing patients presents its own set of issues, as doctors strive to combine acute symptom relief with long-term management goals, all within the context of personalized treatment. Focused research targeted at generating consistent recommendations is vital for advancing understanding and improving patient outcomes.

10. Identifying the key contributions of our GLAV

This chapter outlined the distinct features of GLAV in connection to ETD, emphasizing the importance of minor pressure variations at ground level. Accurate diagnosis is critical, requiring a systematic strategy to balancing MEP and applying a variety of treatments ranging from pharmaceuticals to vestibular rehabilitation to alleviate symptoms.

Advances in diagnostic procedures, personalized treatment plans, and the use of emerging technologies indicate substantial progress in the treatment of GLAV. A better understanding of its pathogenesis, as well as the development of prevention interventions, is required. Furthermore, comprehensive patient education initiatives and collaborative research activities are critical in moving this subject forward.

It is essential to reassess past and recent cases of vertigo for diagnostic accuracy. The use of tympanometry into diagnostic reports for vertigo patients is a crucial opportunity for improved GLAV identification, although its potential is underutilized. A determined attempt to systematically incorporate tympanometric evaluations—and to revisit earlier cases that may lack such data—can result in a reevaluation of diagnoses, encouraging a more detailed understanding of VD. This rigorous refinement of diagnostic methods is critical to the advancement of otolaryngology and the improvement of patient care.

The addition of rigorous diagnostic assessments, such as tympanometry, is critical in the progression of GLAV research. Updating diagnosis, both historical and current, will improve our understanding and the quality of care provided to patients suffering from vertigo-related conditions. Accepting these breakthroughs is critical to the ongoing improvement of otolaryngological treatments and patient health.

Conflict of interest

The author declares no conflict of interest.