A relative weight analysis of the Chinese version of WAB

Purposes

Investigating the contribution of each component of the Western Aphasia Battery (WAB) to the aphasia quotient (AQ) helps better understand the mechanisms of change in the AQ. Previous studies on patients with English-speaking aphasia have shown that spontaneous speech contributes the most to the AQ. However, the same conclusion may not be applicable to Chinese-speaking patients with aphasia because of the differences between Chinese and English languages. The primary objective of this study was to investigate differences between Chinese and English people with aphasia in the contribution of WAB components to the AQ. The second objective was to explore the effect of aphasia severity to the AQ.

Methods

A total of 94 patients with Mandarin aphasia participated in this study. The Lmg and Pmvd algorithms based on relative weight analysis were conducted to calculate the contributions of the four main components and 10 subtests of the WAB to the AQ. Lmg measures the relative importance of each variable by allocating the explanatory power of the model, while Pmvd analyses through a decomposition method based on statistical explanatory quantities. In addition, the same method was applied to the severe, moderate and mild aphasia groups.

Results

Of the four main components, naming contributed the most to the AQ, followed by spontaneous speech, listening comprehension and repetition. Object naming contributed the most among the 10 subtests. Among the different severity groups, naming contributed the most to the severe and moderate groups, while spontaneous speech contributed the most to the mild group.

Conclusions

There were significant differences between Chinese and English patients with aphasia in terms of the contribution of each component of the WAB to the AQ. In Chinese, the largest contributor is naming, as opposed to spontaneous speech in English. Therefore, in a cross-linguistic context, it is important to carefully consider the impact of language differences, as this may help explain and understand the severity of Chinese aphasia.

WHAT THIS PAPER ADDS

What is already known on the subject

• Among native English-speaking patients with mild aphasia, Spontaneous Speech test contributed most to the aphasia quotient of the Western Aphasia Battery. However, it is not known whether this finding applies to Chinese-speaking patients with aphasia as well as those with moderate-to-severe aphasia.

What this study adds to the existing knowledge

• The subjects of our study were native speakers of Chinese with aphasia, and the results showed that the scores of the Naming test contributed the most to the total score. Further studies found that when grouped by severity, the Spontaneous Speech test contributed the most to the total score in the mild group, and the Naming test contributed the most to the total score in the moderate and severe groups.

What are the clinical implications of this work?

• Patients with Chinese aphasia of different severity effectively improve their aphasia quotient in different ways. Mild patients correspond to spontaneous speech while moderate to severe patients correspond to naming. This may provide suggestions for the rehabilitation of patients.