2020 年 79 巻 2 号 p. 62-70
Persistent postural-perceptual dizziness (PPPD) is a newly defined diagnostic syndrome that was included in the 11th edition of the World Health Organization's International Classification of Diseases (ICD-11) in 2018. PPPD is characterized by persistent chronic vestibular syndrome, typically preceded by acute vestibular disorders, lasting for >3 months. The core vestibular symptoms of PPPD are dizziness, unsteadiness, and/or non-spinning vertigo and are exacerbated by upright posture/walking, active or passive movements, and exposure to moving or complex visual stimuli. PPPD is classified as a functional disorder, and not as a structural or psychiatric condition. No specific laboratory tests for the diagnosis of PPPD are available, and an assessment of the symptoms, exacerbating factors, and medical history is important for the precise diagnosis of PPPD. Although the exact pathophysiology of PPPD remains to be elucidated, data from physiological investigations and rapidly emerging advanced structural and functional neuroimaging studies have revealed some key mechanisms underlying the development of this disorder, including stiffened postural control, a shift in processing spatial orientation information to favor visual or somatosensory over vestibular inputs, and failure of higher cortical mechanisms to modulate the first two processes. Although PPPD is a relatively new diagnosis and will therefore be unfamiliar to many health professionals, undiagnosed or untreated dizzy patients who have been suffering for many years can be saved. Once recognized, PPPD can be managed by effective communication and individually tailored treatment strategies, including serotonergic medications, vestibular rehabilitation and cognitive behavioral therapy.