Early detection of behavioral side effects of antiepileptic treatment using handheld computers

Extended ambulatory assessment of executive function: within-person reliability of working memory and inhibitory control tasks

INTRODUCTION

Ambulatory assessment of executive function - particularly in the form working memory (WM) - is increasingly common. Few studies to date, however, have also incorporated ambulatory measures of inhibitory control. Critically, the extended within-person reliability of ambulatory tasks tapping each of these constructs has been largely overlooked.

METHOD

Participants (N = 283, Mage = 23.74 years, SD = 9.04) received notifications every 3 days (for 4 weeks) to undertake ambulatory assessment versions of the n-Back and Stop-Signal Tasks (SST) via the smartphone application CheckCog. Within-person reliability of these measures was explored.

RESULTS

Compliance ranged from 66% (for eight sessions) to 89% (for four sessions). Our results reveal significant changes in performance within the first two sessions for both the n-Back and SST, with performance remaining largely consistent across the remaining (two to eight) sessions. In terms of test-retest reliability, the ICC (C, 1) values ranged from .29 to .68 on the n-Back (with overall accuracy being .51) and .31-.73 on the SST (with stop-signal reaction time being .53).

CONCLUSION

The results of the current study contribute to the literature by demonstrating the reliability of brief measures of executive function - in the form of inhibitory control and WM - delivered using smartphones in participants' natural environments. Based on our findings, the CheckCog app reliability tracks baseline systematic changes in WM and response inhibition across multiple time points and for an extended period in healthy individuals.

Wearable Computing Technology for Assessment of Cognitive Functioning of Bipolar Patients and Healthy Controls

Mobile cognitive tests have been emerged to first, bring the assessments outside the clinics and second, frequently measure individuals' cognitive performance in their free-living environment. Patients with Bipolar Disorder (BD) suffer from cognitive impairments and poor sleep quality negatively affects their cognitive performance. Wearables are capable of unobtrusively collecting multivariate data including activity and sleep features. In this study, we analyzed daily attention, working memory, and executive functions of patients with BD and healthy controls by using a smartwatch-based tool called UbiCAT to 1) investigate its concurrent validity and feasibility, 2) identify digital phenotypes of mental health using cognitive and mobile sensor data, and 3) classify patients and healthy controls on the basis of their daily cognitive and mobile data. Our findings demonstrated that UbiCAT is feasible with valid measures for in-the-wild cognitive assessments. The analysis showed that the patients responded more slowly during the attention task than the healthy controls, which could indicate a lower alertness of this group. Furthermore, sleep duration correlated positively with participants' working memory performance the next day. Statistical analysis showed that features including cognitive measures of attention and executive functions, sleep duration, time in bed, awakening frequency and duration, and step counts are the digital phenotypes of mental health diagnosis. Supervised learning models was used to classify individuals' mental health diagnosis using their daily observations. Overall, we achieved accuracy of approximately 74% using K-Nearest Neighbour (KNN) method.

Bridging the gap between performance-based assessment and self-reported everyday functioning: An ecological momentary assessment approach

Objective: In the real-world environment, multiple and interacting state-dependent factors (e.g., fatigue, distractions) can cause cognitive failures and negatively impact everyday activities. This study used ecological momentary assessment (EMA) and a n-back task to examine the relationship between fluctuating levels of cognition measured in the real-world environment and self-report and performance-based measures of functional status.Method: Thirty-five community-dwelling older adults (M age = 71.80) completed a brief battery of objective and self-report measures of cognitive and functional status. After completing 100, 45-second trials to reach stable performance on a n-back task, EMA data collection began. Four times daily for one week, participants received prompts on a tablet to complete a n-back task and a brief survey. From the EMA n-back trials, measures of EMA average performance and intra-individual variability (IIV) across performances were created.Results: For the EMA n-back, the correlation between IIV and EMA average was weak and non-significant. IIV associated with self-report measures, and EMA average with the objective, performance-based functional status composite. Hierarchical regressions further revealed that IIV was a significant predictor of self-reported functional status and cognitive failures over and above EMA average performance and global cognitive status. In contrast, for the objective, functional status composite, IIV did not explain additional variance.Conclusions: The findings suggest that IIV and self-report measures of functional status and cognitive failures may capture a real-world cognitive capacity that fluctuates over time and with context; one that may not easily be captured by objective, performance-based measures designed to assess optimal function.

Digital assessment of working memory and processing speed in everyday life: Feasibility, validation, and lessons-learned

OBJECTIVES

Cognitive functioning is often impaired in mental and neurological conditions and might fluctuate throughout the day. An existing experience-sampling tool was upgraded to assess individual's cognition in everyday life. The objectives were to test the feasibility and validity of two momentary cognition tasks.

METHODS

The momentary Visuospatial Working Memory Task (mVSWMT) and momentary Digit Symbol Substitution Task (mDSST) were add-ons to an experience sampling method (ESM) smartphone app. Healthy adults (n = 49) between 19 and 73 years of age performed the tasks within an ESM questionnaire 8 times a day, over 6 consecutive days. Feasibility was determined through completion rate and participant experience. Validity was assessed through contextualization of cognitive performance within intrapersonal and situational factors in everyday life.

FINDINGS

Participants experienced the tasks as pleasant, felt motivated, and the completion rate was high (71%). Social context, age, and distraction influenced cognitive performance in everyday life. The mVSWMT was too difficult as only 37% of recalls were correct and thus requires adjustments (i.e. fixed time between encoding and recall; more trials per moment). The mDSST speed outcome seems the most sensitive outcome measure to capture between- and within-person variance.

CONCLUSIONS

Short momentary cognition tasks for repeated assessment are feasible and hold promise, but more research is needed to improve validity and applicability in different samples. Recommendations for teams engaging in the field include matching task design with traditional neuropsychological tests and involving a multidisciplinary team as well as users. Special attention for individual needs can improve motivation and prevent frustration. Finally, tests should be attractive and competitive to stimulate engagement, but still reflect actual cognitive functioning.

Applications for self-administered mobile cognitive assessments in clinical research: A systematic review

Frequent, brief and repeated self-administered mobile assessments of cognitive function, conducted in everyday life settings, are a promising complementary tool to traditional assessment approaches. Mobile cognitive assessments promote patient-centered care and might enhance capacity to inform individual-level outcomes over time (i.e. detecting subtle declines in cognitive function), as well as in assessing cognition and its correlates in the naturalistic environment. The goal of this systematic review was to assess the feasibility and psychometric properties of mobile cognitive assessments. Through a comprehensive search, we identified 12 articles using self-administered, mobile phone-based cognitive assessments. Studies sampled participants between 1 and 6 times per day for 1-14 days. Samples ranged in age from 14 to 83 years old and were generally healthy populations without cognitive impairment. Working memory was the most frequently-assessed cognitive domain (n = 7), followed by attention/reaction time (n = 4). Seven studies reported adherence, with mean adherence rates of 79.2%. In addition to positive evidence of feasibility, there was general support for high levels of between- and within-person reliability and construct validity. While research has only begun to explore the utility of mobile cognitive assessments, studies to-date indicate they may be a promising complementary tool to traditional assessment methods with potential to improve clinical care and research.

Seizure detection, seizure prediction, and closed-loop warning systems in epilepsy

Nearly one-third of patients with epilepsy continue to have seizures despite optimal medication management. Systems employed to detect seizures may have the potential to improve outcomes in these patients by allowing more tailored therapies and might, additionally, have a role in accident and SUDEP prevention. Automated seizure detection and prediction require algorithms which employ feature computation and subsequent classification. Over the last few decades, methods have been developed to detect seizures utilizing scalp and intracranial EEG, electrocardiography, accelerometry and motion sensors, electrodermal activity, and audio/video captures. To date, it is unclear which combination of detection technologies yields the best results, and approaches may ultimately need to be individualized. This review presents an overview of seizure detection and related prediction methods and discusses their potential uses in closed-loop warning systems in epilepsy.

Ambulant cognitive assessment using a smartphone

The focus of neuropsychology is to understand the relationship between assessment results and everyday cognitive abilities and disabilities. However, the generalizability of traditional neuropsychological tests to real-life behaviors, the ecological validity, is compromised by the test environment, among other things. Neuropsychological tests are often completed in a laboratory setting that is typically quiet with few distractions. This is very unlike most everyday environments. The aim of the present study was to investigate the possibility of using a smartphone in standardized cognitive assessment. A short-term memory task was obtained from young adults in either an everyday-life environment or a controlled test setting at four time points during a day. Results show no significant differences between the task performances in both conditions. There was no indication that fatigue, tension, or environmental noise had an effect on task performance. High correlations between subsequent time points were found in the everyday-life environment, suggesting a high test-retest reliability and commitment of the participants. The present study demonstrates that smartphones can be used to assess cognitive functions outside a laboratory setting.

Challenges for emerging neurostimulation-based therapies for real-time seizure control

In step with the worthwhile aim of this special issue, two junior investigators impart their insights on the therapeutic challenges imposed by pharmacoresistant epilepsies and offer viable approaches to improvement of treatment outcomes. Sunderam's comprehensive perspective addresses issues of critical importance for the design of efficacious therapies. Talathi delves into the thorny roles of so-called "interictal" spikes in ictio- and epileptogenesis, roles that are central to understanding the dynamics of these phenomena and implicitly of how to prevent them or abort them. First, however, Osorio and co-workers illustrate the complex behavior of the epileptogenic network and point to the importance of real-time intraindividual adaptation and optimization of therapies for seizures originating from the same epileptogenic network.

Toward rational design of electrical stimulation strategies for epilepsy control

Electrical stimulation is emerging as a viable alternative for patients with epilepsy whose seizures are not alleviated by drugs or surgery. Its attractions are temporal and spatial specificity of action, flexibility of waveform parameters and timing, and the perception that its effects are reversible unlike resective surgery. However, despite significant advances in our understanding of mechanisms of neural electrical stimulation, clinical electrotherapy for seizures relies heavily on empirical tuning of parameters and protocols. We highlight concurrent treatment goals with potentially conflicting design constraints that must be resolved when formulating rational strategies for epilepsy electrotherapy, namely, seizure reduction versus cognitive impairment, stimulation efficacy versus tissue safety, and mechanistic insight versus clinical pragmatism. First, treatment markers, objectives, and metrics relevant to electrical stimulation for epilepsy are discussed from a clinical perspective. Then the experimental perspective is presented, with the biophysical mechanisms and modalities of open-loop electrical stimulation, and the potential benefits of closed-loop control for epilepsy.

Alcohol and cognitive function: assessment in everyday life and laboratory settings using mobile phones

BACKGROUND

Mobile phone (cellphone) technology makes it practicable to assess cognitive function in a natural setting. We assessed this method and compared impairment of performance due to alcohol in everyday life with measurements made in the laboratory.

METHODS

Thirty-eight volunteers (20 male, aged 18-54 years) took part in the everyday study, completing assessments twice a day for 14 days following requests sent by text messages to the mobile phone. Twenty-six of them (12 male, aged 19-54) took part in a subsequent two-period crossover lab study comparing alcohol with no alcohol (placebo).

RESULTS

Everyday entries with 5 or more units of alcohol consumed in the past 6 hours (inferred mean blood alcohol concentration 95 ml/100 ml) showed higher scores for errors in tests of attention and working memory compared with entries with no alcohol consumed that day. Response times were impaired for only 1 test, sustained attention to response. The laboratory comparison of alcohol (mean blood alcohol concentration 124 mg/100 ml) with placebo showed impairment to both reaction time and error scores for all tests. A similar degree of subjective drunkenness was reported in both settings.

CONCLUSIONS

We found that mobile phones allowed practical research on cognitive performance in an everyday life setting. Alcohol impaired function in both laboratory and everyday life settings at relevant doses of alcohol.