Feasibility of using smartphones to capture speech during social interactions in schizophrenia

The Influence of Greenspace Exposure on Affect in People With and Those Without Schizophrenia: Exploratory Study

BACKGROUND

Exposure to natural vegetation (ie, "greenspace") is related to beneficial outcomes, including higher positive and lower negative affect, in individuals with and those without mental health concerns. Researchers have yet to examine dynamic associations between greenspace exposure and affect within individuals over time. Smartphone-based ecological momentary assessment (EMA) and passive sensors (eg, GPS, microphone) allow for frequent sampling of data that may reveal potential moment-to-moment mechanisms through which greenspace exposure impacts mental health.

OBJECTIVE

In this study, we examined associations between greenspace exposure and affect (both self-reported and inferred through speech) in people with and those without schizophrenia spectrum disorder (SSD) at the daily level using smartphones.

METHODS

Twenty people with SSD and 14 healthy controls reported on their current affect 3 times per day over 7 days using smartphone-based EMA. Affect expressed through speech was labeled from ambient audio data collected via the phone's microphone using Linguistic Inquiry and Word Count (LIWC). Greenspace exposure, defined as the normalized difference vegetation index (NDVI), was quantified based on continuous geo-location data collected from the phone's GPS.

RESULTS

Overall, people with SSD used significantly more positive affect words (P=.04) and fewer anger words (P=.04) than controls. Groups did not significantly differ in mean EMA-reported positive or negative affect, LIWC total word count, or NDVI exposure. Greater greenspace exposure showed small to moderate associations with lower EMA-reported negative affect across groups. In controls, greenspace exposure on a given day was associated with significantly lower EMA-reported anxiety on that day (b=-0.40, P=.03, 95% CI -0.76 to -0.04) but significantly higher use of negative affect words (b=0.66, P<.001, 95% CI 0.29-1.04). There were no significant associations between greenspace exposure and affect at the daily level among participants with SSD.

CONCLUSIONS

Our findings speak to the utility of passive and active smartphone assessments for identifying potential mechanisms through which greenspace exposure influences mental health. We identified preliminary evidence that greenspace exposure could be associated with improved mental health by reducing experiences of negative affect. Future directions will focus on furthering our understanding of the relationship between greenspace exposure and affect on individuals with and those without SSD.

Social functioning in schizophrenia: Comparing laboratory-based assessment with real-world measures

Researchers have measured social functioning in schizophrenia using many different strategies. Recent technological advances have made it possible to passively measure behaviors in real-world social situations-allowing for more objective, ecologically valid assessments. Yet, research testing the convergent validity among real-world and laboratory-based social functioning assessment is sparse. The purpose of this study was to test the convergent validity among four social functioning measures: two interview-based rating scales, a self-reported ecological momentary assessment (EMA), and a passive, ambulatory ecological assessment. Data was collected from 36 people with schizophrenia and 33 control participants. Across the entire sample, relationships between interview-based ratings and real-world measures of social functioning only demonstrated small correlations (r's = 0.17-0.19), whereas real-world measures exhibited moderate correlations with one another (r = 0.36). Within groups, real-world measures showed moderate, significant relationships in the control group (r = 0.44) but not in the schizophrenia group (r = 0.27). For those with schizophrenia, the interview-based measures of social functioning were moderately associated with ambulatory ecological assessment (r's = 0.38 and 0.47), but only small associations were observed with self-reported EMA (r's = 0.15 and 0.17). Results suggest social functioning assessments are not highly convergent and likely target different aspects of social functioning. Laboratory-based measures offer global impressions of social functioning whereas real-world measures represent a more nuanced approach. Moreover, ambulatory ecological assessment may most accurately gauge frequency of daily social interactions for those with schizophrenia as it circumvents common pitfalls of self-report and offers a less-biased, in-depth evaluation of social behavior.