Answering the missed call: Initial exploration of cognitive and electrophysiological changes associated with smartphone use and abuse

BackgroundSmartphone usage is now integral to human behavior. Recent studies associate extensive usage with a range of debilitating effects. We sought to determine whether excessive usage is accompanied by measurable neural, cognitive and behavioral changes.MethodSubjects lacking previous experience with smartphones (n = 35) were compared to a matched group of heavy smartphone users (n = 16) on numerous behavioral and electrophysiological measures recorded using electroencephalogram (EEG) combined with transcranial magnetic stimulation (TMS) over the right prefrontal cortex (rPFC). In a second longitudinal intervention, a randomly selected sample of the original non-users received smartphones for 3 months while the others served as controls. All measurements were repeated following this intervention.ResultsHeavy users showed increased impulsivity, hyperactivity and negative social concern. We also found reduced early TMS evoked potentials in the rPFC of this group, which correlated with severity of self-reported inattention problems. Heavy users also obtained lower accuracy rates than nonusers in a numerical processing. Critically, the second part of the experiment revealed that both the numerical processing and social cognition domains are causally linked to smartphone usage.ConclusionHeavy usage was found to be associated with impaired attention, reduced numerical processing capacity, changes in social cognition, and reduced right prefrontal cortex (rPFC) excitability. Memory impairments were not detected. Novel usage over short period induced a significant reduction in numerical processing capacity and changes in social cognition.研究背景：智能手机使用现已成为人类行为不可或缺的组成部分。既往多项研究表明，过度使用智能手机会引发一系列损害性健康后果。本研究旨在探究过度使用智能手机是否会伴随可观测到的神经、认知及行为层面的改变。 研究方法：将无智能手机使用史的受试者（n=35）与匹配的重度智能手机使用者队列（n=16）进行对比，通过结合右侧前额叶皮层（right prefrontal cortex, rPFC）经颅磁刺激（transcranial magnetic stimulation, TMS）的脑电图（electroencephalogram, EEG）技术，记录多项行为学及电生理指标。在第二项纵向干预实验中，随机选取部分初始无使用史的受试者配发智能手机，为期3个月，其余受试者作为对照。干预结束后，对所有受试者重复上述指标测量。 研究结果：重度使用者表现出更高的冲动性、多动性及消极社交关注度。本研究还观察到，该组受试者右侧前额叶皮层的早期经颅磁刺激诱发电位幅值降低，且这一现象与自我报告的注意力不集中症状严重程度呈正相关。此外，重度使用者在数字加工任务中的准确率显著低于无使用史受试者。尤为关键的是，实验第二部分结果表明，数字加工与社会认知两大领域均与智能手机使用存在因果关联。 研究结论：本研究发现，过度使用智能手机与注意力受损、数字加工能力下降、社会认知改变以及右侧前额叶皮层兴奋性降低显著相关。本研究未检测到记忆功能损伤。短期首次使用智能手机即可显著降低数字加工能力，并引发社会认知层面的改变。