Alzheimer's disease (AD) manifests with memory loss and spatial disorientation. AD pathology starts in the entorhinal cortex, making it likely that local neural correlates of spatial navigation, particularly grid cells, are impaired. Grid-cell-like representations in humans can be measured using functional magnetic resonance imaging. We found that young adults at genetic risk for AD (APOE-ε4 carriers) exhibit reduced grid-cell-like representations and altered navigational behavior in a virtual arena. Both changes were associated with impaired spatial memory performance. Reduced grid-cell-like representations were also related to increased hippocampal activity, potentially reflecting compensatory mechanisms that prevent overt spatial memory impairment in APOE-ε4 carriers. Our results provide evidence of behaviorally relevant entorhinal dysfunction in humans at genetic risk for AD, decades before potential disease onset.

BackgroundMounting evidence shows that smartphone usage heavily disrupts our work life and social activities. Moreover, it is possible that overuse could resemble addictive tendencies. A key contributing factor to smartphone overuse seems to be usage of the messaging application WhatsApp. Although WhatsApp is one of the most commonly used communication applications on smartphones, research in this area is scarce. Given the huge societal debate on the impact of smartphone usage on our daily lives, the present study undertook a large-scale investigation in order to provide numbers on smartphone usage generally—and use of WhatsApp in particular, with the aim of providing a basis for a scientific debate.MethodsIn a large sample of N = 2,418 users, we recorded WhatsApp behaviour over a 4 week period.ResultsOur data show that use of WhatsApp accounted for 19.83% (= 32.11 min) of all smartphone behaviour (compare: Facebook only 9.38% = 15.19 min). The mean of general daily smartphone usage was 161.95 min. Females used WhatsApp for significantly longer periods of time than males and younger age was associated with longer duration of WhatsApp use. While the personality trait Extraversion was positively associated with daily WhatsApp use, Conscientiousness showed an inverse correlation with the length of daily WhatsApp use.ConclusionsThe numbers on smartphone usage in the present study show that the smartphone dominates our daily life. In particular WhatsApp is a driving force, here. Given the length of daily smartphone and WhatsApp usage, more studies need to be conducted to better understand smartphone usage.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-015-1280-z) contains supplementary material, which is available to authorized users.

Aims: The present theoretical paper introduces the smartphone technology as a challenge for diagnostics in the study of Internet use disorders and reflects on the term “smartphone addiction.”Methods: Such a reflection is carried out against the background of a literature review and the inclusion of Gaming Disorder in ICD-11.Results: We believe that it is necessary to divide research on Internet use disorder (IUD) into a mobile and non-mobile IUD branch. This is important because certain applications such as the messenger application WhatsApp have originally been developed for smartphones and enfold their power and attractiveness mainly on mobile devices.Discussion and conclusions: Going beyond the argumentation for distinguishing between mobile and non-mobile IUD, it is of high relevance for scientists to better describe and understand what persons are actually (over-)using. This is stressed by a number of examples, explicitly targeting not only the diverse contents used in the online world, but also the exact behavior on each platform. Among others, it matters if a person is more of an active producer of content or passive consumer of social media.

Introduction Smartphones are ubiquitous in the digital society. Although this powerful device is useful because it supports and simplifies many tasks in everyday life, a growing number of researchers is concerned that smartphones might have detrimental effects on the human brain and related psychological processes. Evidence indicates that social media platforms such as WhatsApp and Facebook are essential drivers of smartphone usage. Thus, a critical, yet unexplored issue is how excessive use of those platforms is related to Smartphone Use Disorder (SUD). Furthermore, since the roles of life satisfaction and fear of missing out (FoMo) have been demonstrated to be of particular importance for Internet Use and Internet Communication Disorder, those constructs were examined in the context of SUD. Methods In total, n = 2299 participants filled in questionnaires assessing SUD, WhatsApp and Facebook Use Disorder, FoMO, life satisfaction, and reported owning a WhatsApp and Facebook account. Results The study revealed that SUD was linked to WhatsApp Use Disorder, and to a lesser extent, to Facebook Use Disorder. Associations between SUD and WhatsApp Use Disorder were most strongly pronounced in females. Additionally, FoMo predicted SUD, WhatsApp, Facebook Use Disorder, and (fully) mediated the relationship between life satisfaction and those variables. Conclusion The findings of the present study suggest that WhatsApp use plays an important role to understand SUD. Regarding the mediating role of FoMO, the present work might help disentangle inconsistent results on the link between life satisfaction and (excessive) social networking sites use.

Recent studies have yielded initial evidence for an association between Internet Use Disorder (IUD), empathy, and life satisfaction. In the present study we sought to replicate these previous findings, and then to extend this research by also examining the relationship between empathy, life satisfaction, and the related phenomenon of Smartphone Use Disorder (SUD). The present study included independent samples from China (N = 612, 162 females) and Germany (N = 304, 207 females), with the same set of questionnaires administered to both samples. IUD was measured with Pawlikowski's s-IAT and SUD was assessed with the short version of Kwon's Smartphone Addiction Scale. The Interpersonal Reactivity Index (IRI) was used to assess individual differences in empathy. Please note that for the German sample data on the empathy quotient (EQ) are also available. Life satisfaction data were collected using items from the SOEP-Questionnaire (Socio-Economic Panel, Germany). In both of our samples we replicated previous findings showing the association between higher IUD, lower empathy, and lower life satisfaction scores. In addition, individuals with higher SUD showed higher scores on the IRI Personal Distress scale in China and Germany, while further associations between IRI dimensions and SUD were only found in the Chinese sample. Personal Distress is known to be highly correlated with the personality trait of Neuroticism, hence higher stress/negative emotionality in tense social situations is related to SUD. In the present study we confirm earlier findings showing the relationship between empathy, life satisfaction, and IUD, and extend some of these findings to SUD. We also emphasize the importance of cross-cultural studies when investigating IUD/SUD in the context of empathy and life satisfaction.