Introduction: Usher syndrome is a genetic condition causing deaf-blindness and is one of the most common causes of syndromic deafness. Individuals with USH1 in Sweden born during the last 15 years have typically received cochlear implants (CI) as treatment for their congenital, profound hearing loss. Recent research in genetics indicate that the cause of deafness in individuals with Usher type 1 (USH1) could be beneficial for the outcome with cochlear implants (CI). This population has not previously been the focus of cognitive research.

Objective: The present study aims to examine the phonological and lexical skills and working memory capacity (WMC) in children with USH1 and CI and to compare their performance with children with NH, children with hearing-impairment using hearing-aids and to children with non-USH1 deafness using CI. The participants were 7 children aged 7-16 years with USH1 and CI.

Methods: The participants performed 10 sets of tasks measuring phonological and lexical skills and working memory capacity.

Conclusions: The results indicate that children with USH1 and CI as a group in general have a similar level of performance on the cognitive tasks as children with hearing impairment and hearing aids. The group with USH1 and CI has a different performance profile on the tests of working memory, phonological skill and lexical skill than children with non-USH1 deafness using CI, on tasks of phonological working memory and phonological skill.

Objective: The aim of this study was to explore and describe reading skill in children with Usher syndrome type 1 and who have cochlear implants (USH1+CI), and to position their performance in relation to that of three control groups: children with normal hearing (NH), children with hearing impairment and hearing aids (HI+HA), and children with other types of deafness and CI (other CI).

Method: Reading comprehension and decoding was measured in five children with USH1+CI in the ages 7.5–16 years. The children participated during a test session of 2–2.5 hours and performed tests including reading skill, WM, phonological skills, and lexical skills.

Results: Four of the children with USH1+CI achieved results similar to those of the control group with NH on the measures of reading skill. One child with USH1+CI performed below all control groups. Three of the children with USH1+CI had high performance on both the measures of phonological skill and on the tests of reading skill. The groups perform similar results on the tests of reading skill.

Conclusions: Three of the children with USH1+CI decode non-words with a phonological decoding strategy, similar to the strategy applied by the control group with NH. Two of the children with USH1+CI relied on an orthographic decoding strategy, possibly relying on other cognitive skills than the phonological strategy.

Objective: To investigate working memory (WM), phonological skills, lexical skills, and reading comprehension in adults with Usher syndrome type 2 (USH2). Design: The participants performed tests of phonological processing, lexical access, WM, and reading comprehension. The design of the test situation and tests was specifically considered for use with persons with low vision in combination with hearing impairment. The performance of the group with USH2 on the different cognitive measures was compared to that of a matched control group with normal hearing and vision (NVH). Study Sample: Thirteen participants with USH2 aged 21-60 years and a control group of 10 individuals with NVH, matched on age and level of education. Results: The group with USH2 displayed significantly lower performance on tests of phonological processing, and on measures requiring both fast visual judgment and phonological processing. There was a larger variation in performance among the individuals with USH2 than in the matched control group. Conclusion: The performance of the group with USH2 indicated similar problems with phonological processing skills and phonological WM as in individuals with long-term hearing loss. The group with USH2 also had significantly longer reaction times, indicating that processing of visual stimuli is difficult due to the visual impairment. These findings point toward the difficulties in accessing information that persons with USH2 experience, and could be part of the explanation of why individuals with USH2 report high levels of fatigue and feelings of stress (Wahlqvist et al., 2013).

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.