Persistent Postural-Perceptual Dizziness

Etiology

The direct cause of the disorder is unknown, but it is thought to be caused by a disruption within or between the visual and postural control mechanisms.[4] The initial trigger may be neuro-otologic, metabolic conditions, allergies, and psychological distress. Commonly, the symptoms occur after a vestibular insult, such as vestibular neuritis, BPPV, Meniere disease, or other predisposing medical conditions. PPPD can reflect an incomplete recovery after a vestibular event or chronic lingering problems between episodic vestibular events. Psychological factors contribute to the development of PPPD, as it is frequently seen in patients with high anxiety, neuroticism, depression, and high body vigilance.

Epidemiology

Persistent postural-perceptual dizziness is the most common chronic vestibular disorder in people 30 to 50 years of age.[4][5] The condition is seen in children, and females are affected more often than men, with a ratio as high as 4 to 1.[6][7] More research is needed to better identify affected demographics given this recently defined condition.

Pathophysiology

The pathophysiology is not fully understood. A neurotic temperament or pre-existing anxiety may predispose individuals. Following a vestibular insult, medical event, and/or acute psychological distress, it is postulated that a patient's dependence on visual-somatosensory cues, environmental vigilance, and changes in posture occurs. This is exacerbated in individuals with high anxiety and body vigilance, as they further focus on their surroundings and pay closer attention to their posture to compensate for the perceived dizziness.[4] Thus, changes in posture, the motion of self, and visually demanding environments often provoke the symptoms of dizziness, unsteadiness, and non-room spinning vertigo.[6]

History and Physical

It is imperative to get a thorough history in persistent postural-perceptual dizziness patients, as the diagnostic criteria include symptoms alone. Given the psychological associations, it is important to inquire about anxiety and depression. It is critical to note that PPPD is not a diagnosis of exclusion and that the criteria for diagnosis are quite specific. Vague, nonspecific complaints should be avoided when ruling PPPD in or out. PPPD may also coexist with other disorders. For example, the sensation of veering or swaying to the side is seen, but falls or near falls are not commonly seen in PPPD. Testing is not used to rule in the disorder but rather to rule out other diagnoses.

Physical Exam

Generally, patients presenting with PPPD will have a normal physical and neurological examination. Head Impulse test, Nystagmus, and Test of Skew (HINTS) exam is indicated in acute settings of dizziness and less helpful in a chronic setting; hence, the HINTS exam will be normal.[2] 

On a gait exam, a patient may sway, demonstrating a vestibular imbalance or disruption in compensatory mechanisms, but they will often not fall. It is important to rule out other diagnoses or assess for comorbid conditions.

Evaluation

Persistent postural-perceptual dizziness is a chronic vestibular disorder with a strict diagnosis criterion. The diagnostic criteria for PPPD are described below in the International Classification of Vestibular Disorders. There are five criteria that all must be met.

Patients must experience vestibular symptoms for greater than half of the days over 90 days. These symptoms include unsteadiness, imbalance, dizziness, or non-spinning vertigo. The symptoms should be present for hours rather than minutes or seconds. This helps distinguish the disorder from other disorders like BPPV. The severity may waver, increase or decrease, and change from one person to the next.

The symptoms experienced by patients with PPPD must not be provoked by any specific events like BPPV or orthostatic hypotension. However, symptoms of PPPD can be exacerbated by the patient being in an upright posture, being exposed to actively moving visual stimuli (ex: moving cars, being in a crowded mall), and by attempting motion (active or passive) with disregard to orientation and position.

Another crucial criterion for accurately diagnosing a patient with PPPD is that it must be precipitated by a condition that causes problems with balance. Conditions that can lead to PPPD are other vestibular syndromes like BPPV, vestibular neuritis, or traumatic brain injury. Other conditions that challenge a healthcare provider's treatment plan include neurologic and psychiatric disorders like anxiety and depression. When these conditions are acute or episodic, the disease course may progress to a persistent presentation. In contrast, if the causative condition is a chronic condition, then symptoms can develop at a slower pace and gradually worsen.

Functional impairment is the fourth diagnostic criterion. The disorder must be negatively affecting their lives. Commonly patients state that they feel swaying from side to side while they are, in fact, being still. Patients often report issues with walking and driving.[8]

The final criterion needed to diagnose PPPD correctly is that it must not be better explained by another medical condition.

Recapping the five criteria to diagnose PPPD: non-room-spinning, unsteadiness, and difficulties with a balance must be present for most of the days over a 90 period. Symptoms cannot be provoked but can be exacerbated by changes in position and exposure to certain stimuli. PPPD must be preceded by a condition with acute, episodic, or chronic vestibular symptoms. Patients with PPPD must be troubled by their symptoms and must have impairment to some degree. Finally, PPPD cannot be explained by another medical condition or disorder.

The diagnosis is made based on the history with the criteria listed above. A physical and neurological exam is generally unremarkable. To assess for comorbid conditions, the workup may include a HINTS test, cervical and ocular vestibular evoked myogenic potentials, neuroimaging of the brain with MRI or CT imaging, and audiogram.[9]

Recent research has demonstrated a difference in PPPD patients compared to healthy individuals. Patients with PPPD will demonstrate lower Amplitude of Low-Frequency Fluctuations (ALFF) and lower regional homogeneity (ReHo) in the lower right precuneus and cuneus regions of the brain. The precuneus region is associated with visuospatial imagery, episodic memory retrieval, and self-processing operations. The cutaneous region is often used for visual processing. Thus, supporting PPPD as a vestibular disorder rather than a structural or psychiatric disorder.[7]

Treatment / Management

There is not a single method for treating PPPD. It is essential to understand that dizziness may arise from central, peripheral as well as vascular conditions. For symptomatic relief of dizziness and feelings of unsteadiness, it has been shown that SSRIs and SNRIs can help. Vestibular balance rehabilitation therapy can help manage motion stimuli by training and integrating the movement of eyes, head, and body movements.

The emphasis of this form of physical therapy is to improve both stability and confidence in patients with disorders regarding balance. Cognitive-behavioral therapy has been shown to augment vestibular therapy by decreasing the maladaptive cycle of anxiety and balance control.[10]

Differential Diagnosis

For PPPD to be diagnosed clinically, the five criteria mentioned above must be met. Failure to meet all five portions of the criteria should prompt clinicians to consider other medical conditions. In the workup of a dizzy patient, it is important to consider post-concussive syndrome, stroke, deconditioning, BPPV, vestibular migraine, panic attacks, Meniere’s disease, cardiac dysrhythmias, autonomic disorders, generalized anxiety, peripheral neuropathy, semicircular canal dehiscence, neurodegenerative disorders, functional gait disorder, and hypotension.[6][11]

Prognosis

There is insufficient research to ascertain if persistent postural-perceptual dizziness is a lifelong condition. Patients who receive vestibular balance rehabilitation therapy and cognitive behavioral therapy, along with pharmaceutical management, report a higher quality of life and return to normal activities sooner than those who don’t receive any treatment.[12] 

Studies suggest that those with intervention acutely following a triggering event fare better than those that receive no intervention following an acute triggering event.[6]

Complications

Patients suffering from this condition can develop or exacerbate anxiety, depression, and body vigilance. Secondary complications of persistent postural-perceptual dizziness include neck stiffness, gait disorder, fear of falling, agoraphobia, fatigue, and dissociation. Clinicians must understand that PPPD is not a psychiatric condition and that psychiatric conditions can develop due to PPPD making life worse for patients.[6] 

Fear of leaving home can arise as patients may attempt to avoid a setting in which their symptoms are exacerbated.[13]