In this study, we developed a scale to measure suffering due to sensory differences and investigated the relationship among autistic traits, sensory differences, suffering due to sensory differences, and internalizing problems. Only Low Registration and Sensation Avoiding were correlated with autistic traits, and they also correlated with suffering due to sensory differences and internalizing problems. Path analysis revealed that suffering due to sensory differences related to ASD significantly mediated the relationship between sensory differences related to ASD and internalizing problems.
Some studies have reported that many individuals with ASD showed particularly Low Registration and Sensation Avoiding [14, 19]. This study also indicated that autistic traits were significantly positively correlated with the total score of Low Registration and Sensation Avoiding in healthy individuals. Since some studies have indicated that sensory differences are related to other developmental disorders and other mental disorders [42,43,44], it is also necessary to investigate the relationship between sensory differences and conditions other than ASD.
There was a significant positive correlation between autistic traits and internalizing problems, which is consistent with previous studies on the general population [4, 8]. This result supported the hypothesis that the higher the indication of autistic traits, the greater the internalization of problems.
Regarding the relationship between sensory differences and internalizing problems, previous studies using the AASP showed that total score was associated with anxiety , and that there were correlations between the total score of Sensory Sensitivity and Sensation Avoiding, and anxiety, as well as between Low Registration and symptoms of depression in adolescents . We also found significant positive correlations between internalizing problems and Low Registration, Sensory Sensitivity, and Sensation Avoiding. Our result coincides with the study of Pfeiffer and colleagues , where Sensation Seeking was not highly correlated with internalizing problems. Because in the AASP, Sensation Seeking included few items that asked about experiences that are likely to cause suffering in daily life, that our study found no correlation between Sensation Seeking and internalizing problems was expected. Hence, our hypothesis (i.e., the higher the sensory differences, the higher the internalization of problems) was supported for Low Registration, Sensory Sensitivity, and Sensation Avoiding.
The results of path analysis indicated that the higher the suffering due to sensory differences, the greater the internalization of problems is in those who scored high on Low Registration and Sensation Avoiding. Previous studies have indicated that sensory differences correlate with internalizing problems in the general population [20, 21] but have not revealed the relationship between suffering due to sensory differences and these variables. However, this study indicates that suffering due to sensory differences significantly mediates the relationship between sensory differences and internalizing problems. As the hypothesis was supported, the higher the suffering due to sensory differences is, the greater the internalization of problems, consisting of emotional symptoms and peer problems. Therefore, suffering due to sensory differences is related to anxiety and depression. Moreover, students who experience suffering may have difficulty building a relationship with their peers at university because they have difficulty following the classes. As previously mentioned, suffering due to sensory differences can create obstacles when taking classes, causing stress at university. However, the teaching staff and fellow students at the university may not notice this suffering in class participants. At present, there is little individual support and class styles are diverse. Therefore, it is necessary to determine and provide adequate support for such students.
In this study, we have shown that university students can need support when they have suffering due to sensory differences. Because there were significant positive correlations between internalizing problems and Low Registration, Sensory Sensitivity, and Sensation Avoiding in this study, supports can be needed for suffering related especially to these quadrants. Regarding Sensory Sensitivity, there was no significant correlation with autistic traits, but it was significantly correlated with internalizing problems. Therefore, regardless of the degree of autistic traits, all female university students with high Sensory Sensitivity score may need support. For people with a high Sensory Sensitivity score, concentration can be sustained by providing support strategies such as a reduction in sensory stimulation, incorporating active content to aid concentration, making plans beforehand, and taking a rest . Therefore, students may improve their concentration in class by reducing unnecessary sensory stimulation while increasing speaking opportunities and group discussion.
The total score for Low Registration and Sensation Avoiding significantly correlated with autistic traits. In addition, the greater the suffering due to sensory differences was, the greater the internalization of problems in those who showed these sensory differences. According to Brown and Dunn , for people with a high score for Low Registration, it is useful support to use visual and auditory cues to sharpen and increase the intensity of important stimuli, and to slow their presentation speed. On the other hand, for people with a high Sensation Avoiding score, it is useful support to reduce unnecessary sensory stimulation, to take a rest, to avoid crowds, find a quiet place, and maintain consistency . Therefore, especially for female university students with strong autistic traits, it would be useful to offer small classes, emphasize important stimuli, and maintain a predictable and consistent environment. If it is difficult to change the overall form of the class, individual support according to their suffering maybe useful. For example, to allow them to record the class or attend online. Hence, it is important for faculty members to devise ways to proceed with classes and provide individual support to female university students, especially those with strong autistic traits. These measures may reduce the suffering due to sensory differences in university and partially mitigate internalizing problems.
Furthermore, the present study suggests that suffering due to sensory differences positively correlate with internalizing problems. Therefore, university students with serious suffering due to sensory differences may need support for managing their suffering and internalizing problems elicited by them. Above all, it may be necessary to provide support where responses to items in the questionnaire revealed a relatively high degree of suffering. For example, positive responses to “Sometimes I cannot catch what the teacher says during the class” and “It is distressing to be in a crowded classroom or school cafeteria because I do not like to get too close to others” are useful warnings. On the other hand, the need for support for female university students may be low for items where students report little suffering. However, the assessment of suffering due to sensory differences are based on the AASP, which uses items related to sensory abnormalities that are common in ASD individuals but rarely seen in general population. Therefore, further research on females with ASD is needed because ASD students may suffer even for items where many students reported little or no suffering in this study.
The current study has four limitations to note. First, the sample was limited. Although it is significant that we investigated female university students in the general population for this study, it is necessary to conduct an investigation of male university students and determine if there are gender differences. In addition, it is also necessary to study the general population across a wider range of age groups. Second, there were few items in the questionnaire relating to suffering due to sensory differences at university. We will be able to determine more methods for supporting students by developing more items and analyzing their responses. Furthermore, although we developed the suffering scale based on the AASP and did not include the items in the Sensation Seeking subscale, some items in Sensation Seeking, such as “Seeks all kinds of movement and this interferes with daily routines (for example, can’t sit still, fidgets)” in the original SP, may indicate sensory experiences that induce suffering. Further studies including items of Sensation Seeking and in more varied situations are needed. We also need to standardize this questionnaire in relation to suffering due to sensory differences because we could not sufficiently confirm its reliability and validity in this study. Third, because this study was cross-sectional, it is necessary to conduct a longitudinal study to discover and investigate the causal relationships between each variable. Fourth, the Cronbach’s alphas of the AQ-10, some subscales of suffering due to sensory differences, and internalizing problems measured by the SDQ in this study were not sufficiently high. A previous study reported that the Cronbach’s alpha for AQ-10 was 0.72 in the clinical group and 0.45 in the control groups . The Cronbach’s alpha in our study was 0.69, which may be because our study was conducted with healthy individuals. Further research using more reliable measures, such as the AQ-50, are necessary. Regarding suffering, all subscales included two or three items. More items related to suffering due to sensory differences need to be developed. Moreover, further research should be conducted with individuals who have higher sensory differences because few participants suffered from some items included in the suffering scale. Regarding SDQ, the validation study for the internalizing subscale on the SDQ reported that the Cronbach’s alpha of internalizing problems was 0.66 in the self-reported SDQ and that it indicates better internal reliability than the subscales covering emotional symptoms and peer problems . The Cronbach’s alpha of internalizing problems in our study was 0.68, indicating some degree of reliability. Moreover, further research using more detailed scales is needed to investigate how suffering due to sensory differences relates to anxiety, depression, and peer problems because the SDQ measures relatively broad internalizing problems.
Further research of the general population could reveal sensory differences for factors other than autistic traits, and the resultant suffering. Additionally, this could help design support systems for people with high sensory differences in school and elsewhere, enabling them to lead a better life.