TESTING CAUSAL THEORIES OF PANTOMIMIC DEFICITS IN APHASIA USING PATH-ANALYSIS

For the past several decades it has been recognized that deficits in both pantomime expression and pantomime recognition exist as part of the syndrome of communication deficits associated with aphasia. To test the major theories proposed to explain the cause(s) of these pantomimic deficits and their association with aphasic verbal deficits, path analysis and LISREL were used to analyse five causal models. (Path analysis is a type of structural equation modelling and LISREL is a computer program used to assess the models against the obtained data.) Data were obtained from 41 left-hemisphere-damaged aphasic subjects. The results of the path and LISREL analyses led to the rejection of four of the five models. Three of the four rejected models tested asymbolia, intellectual loss, limb apraxia, and visual processing deficit as sole causal factors; the fourth rejected model was a multicausal model testing intellectual loss, limb apraxia, asymbolia, and visual processing deficit. The one model that proved to be plausible was a multicausal model hypothesizing that pantomimic recognition and expression deficits were caused both by a central symbolic deficit and specific modality factors of limb apraxia and visual processing.