Department of Psychology, University of Georgia, Athens, GA.
Department of Psychology, Louisiana State University, Baton Rouge, LA.
Schizophr Bull. 2020 Dec 1;46(6):1596-1607. doi: 10.1093/schbul/sbaa121.
Negative symptoms and functional outcome have traditionally been assessed using clinical rating scales, which rely on retrospective self-reports and have several inherent limitations that impact validity. These issues may be addressed with more objective digital phenotyping measures. In the current study, we evaluated the psychometric properties of a novel "passive" digital phenotyping method: geolocation.
Participants included outpatients with schizophrenia or schizoaffective disorder (SZ: n = 44), outpatients with bipolar disorder (BD: n =19), and demographically matched healthy controls (CN: n = 42) who completed 6 days of "active" digital phenotyping assessments (eg, surveys) while geolocation was recorded.
Results indicated that SZ patients show less activity than CN and BD, particularly, in their travel from home. Geolocation variables demonstrated convergent validity by small to medium correlations with negative symptoms and functional outcome measured via clinical rating scales, as well as active digital phenotyping behavioral indices of avolition, asociality, and anhedonia. Discriminant validity was supported by low correlations with positive symptoms, depression, and anxiety. Reliability was supported by good internal consistency and moderate stability across days.
These findings provide preliminary support for the reliability and validity of geolocation as an objective measure of negative symptoms and functional outcome. Geolocation offers enhanced precision and the ability to take a "big data" approach that facilitates sophisticated computational models. Near-continuous recordings and large numbers of samples may make geolocation a novel outcome measure for clinical trials due to enhanced power to detect treatment effects.
传统上，阴性症状和功能结果是通过临床评估量表来评估的，这些量表依赖于回顾性的自我报告，存在影响有效性的几个固有局限性。这些问题可以通过更客观的数字表型测量来解决。在当前的研究中，我们评估了一种新的“被动”数字表型方法——地理定位的心理测量特性。
参与者包括精神分裂症或分裂情感障碍（SZ）的门诊患者（n=44）、双相情感障碍（BD）的门诊患者（n=19）和在人口统计学上匹配的健康对照者（CN，n=42），他们在完成 6 天的“主动”数字表型评估（如调查）的同时记录地理定位。
结果表明，SZ 患者的活动量比 CN 和 BD 患者少，特别是在家中出行方面。地理定位变量与阴性症状和功能结果的临床评估量表以及动机缺乏、社交回避和快感缺失等主动数字表型行为指标呈小到中等相关，具有收敛效度。判别效度得到了支持，与阳性症状、抑郁和焦虑的相关性较低。良好的内部一致性和多天的中等稳定性支持了可靠性。
这些发现初步支持了地理定位作为评估阴性症状和功能结果的客观指标的可靠性和有效性。地理定位提供了增强的精度和采用“大数据”方法的能力，从而促进复杂的计算模型。由于能够增强检测治疗效果的能力，接近连续的记录和大量的样本可能使地理定位成为临床试验的一种新的结果测量方法。
