Introduction

Electronystagmography (ENG) and videonystagmography (VENG) are cornerstone assessments for patients presenting with dizziness and balance disorders. These tests objectively measure eye movements, nystagmus, and central or peripheral vestibular function. However, a growing challenge in clinical neurotology is the deliberate feigning or exaggeration of symptoms—a phenomenon known as malingering. This article explores the intersection of malingering with ENG and VENG testing, highlighting detection strategies, red flags, and ethical considerations.

Understanding Malingering in Vestibular Testing

Malingering is defined as the intentional production of false or grossly exaggerated physical symptoms, motivated by external incentives such as financial compensation, avoidance of work, or litigation. In the context of dizziness evaluations, patients may simulate vertigo, imbalance, or nystagmus during ENG or VENG protocols. Because these tests rely on patient cooperation and physiological responses, they are susceptible to manipulation by motivated individuals.

The prevalence of malingering among dizzy patients is not precisely known, but studies suggest that up to 10–20% of medicolegal cases may involve symptom exaggeration or fabrication. Clinicians must maintain a high index of suspicion when objective findings do not match subjective complaints, especially in settings with secondary gain.

Vulnerabilities of ENG/VENG to Malingering

ENG and VENG test specific components of the vestibular-ocular reflex (VOR). The main subtests include positional testing, caloric irrigation, and oculomotor evaluation (saccades, smooth pursuit, optokinetic nystagmus). Each component can be deliberately disrupted by a patient intent on feigning dizziness:

• Caloric Testing: Patients may voluntarily suppress nystagmus by fixating on a target, or they may exaggerate responses by looking in the direction of the fast phase or by hyperventilating.
• Positional Testing: The patient can deliberately move their head in a way that induces true benign paroxysmal positional vertigo (BPPV) or can fake nystagmus by voluntarily moving their eyes.
• Oculomotor Recordings: Saccades and smooth pursuit can be disrupted by lack of effort, voluntary blinking, or purposeful gaze deviation, leading to patterns that mimic central or peripheral vestibular dysfunction.

Modern VENG systems use infrared video cameras to record eye movements, reducing some artifacts but remaining reliant on the patient's cooperation. Behavioral observations, such as exaggerated head movements or inconsistent responses, are key to identifying potential malingering.

Red Flags and Detection Strategies

Several clinical and electrophysiological findings can alert the clinician to possible malingering during ENG/VENG assessments:

• Inconsistency: Marked discrepancy between the patient's reported disability and their observed behavior during the test (e.g., severe dizziness but no objective nystagmus).
• Non-physiological Patterns: Saccadic intrusions, square-wave jerks, or nystagmus that does not follow expected patterns (e.g., direction-changing nystagmus without positional change).
• Fixation Suppression Failure: True vestibular nystagmus is typically suppressed by visual fixation. Patients who feign may fail to suppress their voluntary nystagmus, or they may suppress it too quickly.
• Caloric Asymmetry Without Other Signs: A unilateral caloric weakness that is not corroborated by other vestibular tests or rotational chair findings may indicate poor effort or malingering.
• Symptom Magnification: Patients who report extreme dizziness from minimal stimulation, yet exhibit normal ocular motor recordings, should raise suspicion.

Advanced detection methods include using "symptom validity tests" embedded in the VENG protocol, such as random saccade targets or unpredictable head impulses. Additionally, recording the patient's behavior with video monitoring can capture voluntary eye movements or exaggerated responses.

Clinical Implications and Ethical Considerations

Misdiagnosis of malingering can have serious consequences, including denial of legitimate treatment, legal repercussions, and erosion of trust. Conversely, failing to identify malingering can lead to unnecessary tests, inappropriate treatments, and misuse of healthcare resources. It is essential that clinicians approach possible malingering with careful documentation, objective data, and a non-judgmental attitude.

When malingering is suspected, the audiologist or otoneurologist should repeat the test, use alternative vestibular assessments (such as vestibular evoked myogenic potentials or video head impulse testing), and consult with psychology or neuropsychology for formal performance validity testing. Communication with the referring physician is also critical.

Conclusion

Malingering of ENG and VENG tests represents a significant diagnostic challenge in the evaluation of dizziness. Awareness of the potential for feigned vestibular symptoms, combined with systematic analysis of test patterns and behavioral observations, can improve detection rates. While no single test is definitive, a multi-modal approach—integrating clinical history, objective vestibular measurements, and validity indicators—offers the best path to accurate diagnosis and appropriate management. As healthcare professionals, maintaining a balance between clinical skepticism and compassion remains paramount.