MAST Properties

Several aspects of psychometric properties have been investigated with the MAST. Among a mixed sample of 51 patients with diagnoses including traumatic brain injury, stroke, epilepsy, tumor, and encephalopathy, individuals with left-hemisphere lesions performed significantly worse on the Total Score, Receptive Index, and Expressive Index of the MAST compared to individuals with right-hemisphere lesions (Nakase-Thompson et al., 2002). Similar findings were reported among a sample of 38 acute left hemisphere stroke patients (LH), 21 acute right-hemisphere stroke patients (RH), and 36 normal control subjects (CS; Nakase-Thompson et al., manuscript under preparationa). Individuals in the LH group performed significantly worse on the Index and Total scores compared to individuals in the RH and CS groups (p<0.0005 for all). Inspection of subscale scores revealed that the LH group performed worse on all subscale scores, Index, and Total scores compared to individuals in the CS. Similar significance was found comparing the LH and RH group with the exception that the Object Recognition and Verbal Fluency subscales did not discriminate these two clinical groups. These two studies suggest excellent criterion validity for the MAST in differentiating communication impairments among both clinical and control samples.

Aspects of convergent and divergent validity were investigated with the MAST in a sample of 33 individuals with traumatic brain injury, stroke, dementia, and encephalopathy (Nakase-Thompson et al., 2003). Using non-parametric correlations, the MAST Total score was found to be significantly correlated with other language measures including the Boston Naming Test (r=0.89), MAE Controlled Oral Word Association Test (r=0.57), and MAE Token Test (r=0.79). Divergent validity of the MAST was investigated by examining the relationship with the Mini-Mental Status Exam (MMSE) Total Score and Agitated Behavior Scale. Correlations were not significant as expected (Nakase-Thompson et al., 2003). However, given the relatively small sample size, a follow-up investigation with a larger sample has established a significant correlation between the MAST and MMSE which is a more generalized measure of cognitive functioning and sensitive to language impairments (Nakase-Thompson et al., manuscript in progress). In this larger sample, the MAST maintained a significant correlation with all language measures and the MMSE but did not correlate significantly with a measure of visual-perception (Benton Visual Form Discrimination Test).