Depersonalization-derealization (DD) disorders are a clinical phenomenon characterized by feeling disconnected or detached from one's self. Individuals may report feeling as if they are an outside observer of their own thoughts or body, and often report feeling a loss of control over their thoughts or actions.

Several scales have been developed to measure DD, and the Cambridge Depersonalization Scale (CDS) appears to be the most relevant and consistent to characterize the clinical symptoms of these disorders as well as their duration and frequency. This scale, originally written in English, must be translated and validated according to standardized methods that include testing steps patients with dizziness and in individuals with no vestibular disorder.

Persistent postural-perceptual dizziness (PPPD) is a chronic, persistent vestibular syndrome generally preceded by acute vestibular disorders. The main symptoms are rotational dizziness, unsteadiness and / or non-rotating dizziness that are exacerbated by upright posture, walking, active or passive movement, and exposure to moving visual stimuli or complex visual patterns. To help diagnose this syndrome, a questionnaire was developed in Japan in 2019, the Niigata questionnaire, however no French version has yet been validated. Similarly, this scale needs to be validated in patient with PPPD and in control populations.

The main objective of this study is to validate the French translation of these two scales, the CDS questionnaire and the Niigata PPPD questionnaire, according to standard methods (forward translation, back translation, consensus).

Inclusion Criteria:

For patient:

• Age ≥ 18 years
• Patient with acute or chronic otoneurological disorders
• Patient having or having experienced dizziness and / or balance disorders
• Patient with PPPD
• Fluency in French
• Having given free and informed written consent
• Being affiliated with or benefiting from social security

For control subjects:

• Age ≥ 18 years
• Fluency in French
• Having given free and informed written consent
• Being affiliated with or benefiting from social security.

Exclusion Criteria:

For patient:

-Past or present psychiatric and neurological disease (other than otoneurological or PPPD, as declared by the participant)

For control subjects:

-Past or present psychiatric and neurological disease (as declared by the participant) and vestibular and/or auditory system disorders (as declared by the participant)

For all participants:

• Persons still in a period of exclusion from another study and persons simultaneously participating in another study
• Subject to a measure for the protection of justice