Modification of Threat Interpretation Bias to Reduce Anxiety in Neurodegenerative Movement Disorders (Aim 3)

Who May Qualify: - Clinical diagnosis of Huntington's disease or Parkinson's disease (genetic diagnosis of HD also acceptable) - With anxiety symptoms (NeuroQoL Anxiety ≥12) Who Should NOT Join This Trial: - Cognitive decline precluding ability to consent or complete the intervention (MoCA 5 min/telephone ≤11) - Unable to read and understand English - Does not have regular access to an internet-connected device, capable of downloading and installing the mobile application (i.e., tablet or iPhone running iOS 10 or later or an Android phone running Android 5.0 or later) - Not located in the USA - \<21 years old - Active suicidality based on the answer "yes" to questions 4, 5, or 6b of the Columbia-Suicide Severity Rating Scale (Screen version) Always talk to your doctor about whether this trial is right for you.