A validation study of the Clinician's Tardive Inventory (CTI)

Area of Science:

• Neurology
• Psychiatry
• Movement Disorders

Background:

• Existing clinician-rated scales for tardive dyskinesia (TD) lack comprehensive assessment of evolving clinical signs and functional impairments.
• The Clinician's Tardive Inventory (CTI) was developed by movement disorder specialists and psychiatrists to address these limitations.

Purpose of the Study:

• To test the construct validity of the newly developed Clinician's Tardive Inventory (CTI) for assessing TD.
• To evaluate the CTI's ability to capture both movement severity and functional impacts of TD.

Main Methods:

• Seventy patients with TD were assessed using both the CTI and the Abnormal Involuntary Movement Scale (AIMS).
• Construct validity was determined by correlating the CTI Combined Severity Score (CSS) with the AIMS dyskinesia score using Spearman rho.
• Exploratory analyses examined correlations between the CTI Functional Score and AIMS functional questions, as well as between CSS and CTI Functional Score.

Main Results:

• The CTI CSS demonstrated a high correlation with the AIMS dyskinesia score (rho = .770).
• The CTI Functional Score showed strong correlations with AIMS functional questions 9 (rho = .626) and 10 (rho = .771).
• Movement severity (CSS) and functional impact (CTI Functional Score) were not strongly correlated (rho = .285), aligning with clinical observations.

Conclusions:

• The CTI is a valid instrument for assessing TD, incorporating an updated understanding of its phenomenology.
• The CTI effectively differentiates between TD movement severity and its functional consequences.
• The study confirms that TD movement severity does not directly correlate with functional impairments, highlighting the need for distinct assessment domains.