Symptom validity test performance in the Huntington Disease Clinic

Area of Science:

• Neuropsychology
• Neurology
• Clinical Psychology

Background:

• Symptom validity tests (SVTs) are crucial in neuropsychological assessments to gauge response effort.
• Emerging evidence suggests cognitive impairment, such as dementia, can impact SVT performance.
• Huntington disease (HD) presents a unique challenge due to its progressive cognitive and motor decline.

Purpose of the Study:

• To evaluate the performance of individuals with Huntington disease (HD) on three distinct SVTs.
• To investigate the correlation between SVT outcomes and demographic and clinical factors in HD patients.

Main Methods:

• Assessment of 121 HD patients using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Effort Index (EI).
• Evaluation of 36 HD patients with the Test of Memory Malingering (TOMM).
• Analysis of 43 HD patients using the RBANS Effort Scale (ES).
• Statistical examination of relationships between SVT performance and clinical/demographic variables.

Main Results:

• A high pass rate was observed for the RBANS EI (82%) and TOMM (92%) in HD patients.
• Failure on these SVTs correlated with diminished cognitive function, adaptive skills, and increased motor impairment.
• Only 30% of HD patients passed the RBANS ES, with limited correlation to clinical or demographic factors.

Conclusions:

• Certain SVTs, like the RBANS EI and TOMM, appear more suitable for assessing effort in Huntington disease.
• SVT failure in HD is linked to disease severity, underscoring the need for careful interpretation.
• Cognitive status is a critical consideration when interpreting effort measures in individuals with HD.