Theory-of-mind and cognitive function in adults with Usher and Alström syndromes
2015 (English)Manuscript (preprint) (Other academic)
Objective: Theory-of-Mind (ToM) refers to the ability to impute mental states to one self and to others. ToM was investigated in adults with Usher syndrome type II (USH2) and Alström syndrome (AS) - two syndromes causing acquired deafblindness. The syndromes differ with regard to onset and degree of sensory loss. Individuals with AS in contrast to individuals with USH2 display a high incidence of additional physical diseases. Cognitive shortcomings are generally not observed in USH2 or in AS, but cognitive delay and a delay in receptive language have been reported in AS. The results were compared to adults with normal hearing and vision (NHV).
Methods: Thirteen persons with USH2, 12 persons with AS, and 33 persons with NHV participated. All participants performed a test of working memory capacity and verbal ability. ToM was tested with Happe´s Strange Stories test, taxing the ability to understand the emotions and actions of story characters, comprising a mental condition. The test also include a section of matched stories, tapping verbal problem solving ability in a physical condition, and a set of tasks tapping the ability to recall verbal material.
Results: There were no differences between the three groups in the ability to recall verbal material. Significant differences were however established on working memory, and on verbal problem solving in a physical condition, with higher results for the NHV group. The two groups with deafblindness also displayed poorer ToM performance than the NHV group, by producing fewer correct mental references. The two groups with deafblindness differed from each other also in the ability to produce mental inferences as such, where the USH group outperformed the AS group. Intra-group variability in this ability was also observed within the two syndromal groups. Differences were related to verbal ability, complex working memory capacity, visual status, and to a minor extent auditory capacity. The prevalence and severity of additional physical diseases in AS was not related to ToM performance.
Conclusions: A limited access to information as a function of sensory loss could influence degree of experience of the physical world, but also of social situations and of communication, affecting ToM development negatively. Early loss of visual field and visual acuity was related to ToM performance in individuals with USH2 and AS. Access to information also requires processing skills promoted by effective cognitive skills. Working memory capacity was related to ToM in USH. This relation also points to the contribution of hearing in development of ToM. Differences between the two groups could be a function of genetic conditions, where the gene causing USH2 only affects the ear and the eye, while AS in addition has a multi-systemic pathology with varying onset and degree. Differences in ToM performance in the AS group could however not be directly attributed to health conditions.
Place, publisher, year, edition, pages
Usher syndrome (USH); Alström syndrome (AS); Theory-of-Mind; Deafblindness; physical disorders
Social Sciences Interdisciplinary Psychology
IdentifiersURN: urn:nbn:se:liu:diva-120113OAI: oai:DiVA.org:liu-120113DiVA: diva2:840961