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- Cornell Kärnekull, Stina, 1985-
(författare)
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Auditory and Olfactory Abilities in Blind and Sighted Individuals : More Similarities than Differences
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Blind individuals face various challenges in everyday life because of the lack of visual input. However, since they need to rely on the non-visual senses for everyday tasks, for instance, when navigating the environment, the question has been raised as to whether perceptual and cognitive abilities in these senses may be enhanced. This question has mainly been addressed for auditory and tactile abilities, whereas there is considerably less research into the chemical senses, such as olfaction. However, to determine whether blindness has general effects, different senses and types of tasks should be studied, preferably in one and the same study. Therefore, throughout this thesis, analogous auditory and olfactory tasks that varied in cognitive complexity were studied. In Study I, absolute thresholds, discrimination, identification, episodic recognition (i.e., after a short retention interval), metacognition, and self-reported imagery ability were assessed in early blind, late blind, and sighted participants. The only objective measure on which the blind and sighted clearly differed was the auditory episodic recognition task. The fact that early blind but not late blind participants displayed better memory than the sighted suggested that the onset age of blindness may be important for whether this ability becomes enhanced following blindness. Furthermore, the early blind participants rated their auditory imagery ability higher than the sighted, whereas both early and late blind participants rated their olfactory imagery ability higher than the sighted. In Study II, the participants from Study I were followed up after more than a year and retested on auditory and olfactory episodic recognition and identification. This time, the early blind displayed no advantage over the sighted, suggesting that the influence of blindness on auditory memory may be modulated by the length of the retention interval. Moreover, in line with Study I, identification of sounds and odors was similar in the three groups. In Study III, early blind and sighted participants were examined for potential differences in autobiographical memory as evoked by sounds and odors, respectively. Blindness did not influence the reminiscence bumps (i.e., memory peaks in certain age intervals) or have any clear impact on the number of retrieved sound- or odor-evoked memories. Taken together, the present findings indicate that blindness has no general influence across tasks or sensory modalities. Rather, specific auditory abilities, such as episodic memory, may be enhanced in blind individuals, although such effects may depend on both the onset age of blindness and the length of the retention interval. In conclusion, for most perceptual and cognitive abilities examined, performance seemed unaffected by blindness.
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| 3. |
- Parma, Valentina, et al.
(författare)
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More Than Smell—COVID-19 Is Associated With Severe Impairment of Smell, Taste, and Chemesthesis
- 2020
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 45:7, s. 609-622
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Tidskriftsartikel (refereegranskat)abstract
- Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19–79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (−79.7 ± 28.7, mean ± standard deviation), taste (−69.0 ± 32.6), and chemesthetic (−37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms.
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