To investigate the latent factor structure and construct validity of the Verbal Series Attention Test (VSAT) across clinical patient populations.

Participants included a consecutive series of clinical patients presenting with a primary memory complaint. Each patient underwent a comprehensive neuropsychological assessment and provided informed consent to allow their clinical data to be used for research. Groups formed included 1) No Neurocognitive Disorder [NoND, N=262, mean age=68.8, mean education=16.2, mean MMSE=28.3], 2) Mild Neurocognitive Disorder [MildND, N=337, mean age=72.3, mean education=15.4, mean MMSE=28.7], and 3)

Major Neurocognitive Disorder [MajorND, N=524, mean age=76.5, mean education=14.5, mean MMSE=19.0] with etiologies including suspected Alzheimer’s disease and/or vascular pathology. Latent factors were investigated using exploratory factor analysis (EFA).

EFA was conducted using SAS 9.4 software and the promax (oblique) rotation to reveal the latent factors of the eight timed items of the VSAT in each of the three clinical groups. The structure was essentially identical in all three groups with two primary factors consistently emerging identified as 1-Complex Attention and 2-Simple Attention. Each factor had four items loading with a correlation range of > 0.37 x < 0.92. The internal consistency (Cronbach’s alpha) for the VSAT total score in each group was excellent (NoND a=0.83, MildND a=0.81, and MajorND a=0.84). To investigate construct validity, the VSAT items were entered into factor analysis with measures of attention and executive function (i.e., Digit Span [forward, backward, sequence], Trail Making Test A & B, semantic fluency (animals), Controlled Oral Word Association Test [COWAT, FAS]). All three patient groups were combined (N=950) given the VSAT’s consistent factor structure. Using the same EFA procedure as before, two main factors emerged with the VSAT Complex Attention variables loading on a general complex attention/working memory factor including Trails B, semantic fluency, and Digit Span subtests. The VSAT Simple Attention items loaded on a general attention factor with the VSAT Simple Attention variables and Trails A. COWAT did not load significantly on either factor.

The latent factor structure of the VSAT was consistent across patient populations with excellent internal consistency in each clinical group. The Complex and Simple Attention factors of the VSAT loaded on factors with similar variables identifying the anticipated latent factor structure demonstrating the construct validity of the VSAT across a wide spectrum of cognitive impairment in patients with primary memory complaints ranging from NoND to MajorND. This supports the use of the VSAT in patients across neurocognitive severity. Future studies will further explore additional psychometric properties of this instrument.