Test-retest reliability and reliable change index of the Philips IntelliSpace Cognition digital test battery.

OBJECTIVE: This article provides the test-retest reliability and Reliable Change Indices (RCIs) of the Philips IntelliSpace Cognition (ISC) platform, which contains digitized versions of well-established neuropsychological tests. METHOD: 147 participants (ages 19 to 88) completed a digital cognitive test battery on the ISC platform or paper-pencil versions of the same test battery during two separate visits. Intraclass correlation coefficients (ICC) were calculated separately for the ISC and analog test versions to compare reliabilities between administration modalities. RCIs were calculated for the digital tests using the practice-adjusted RCI and standardized regression-based (SRB) method. RESULTS: Test-retest reliabilities for the ISC tests ranged from moderate to excellent and were comparable to the test-retest reliabilities for the paper-pencil tests. Baseline test performance, retest interval, age, and education predicted test performance at visit 2 with baseline test performance being the strongest predictor for all outcome measures. For most outcome measures, both methods for the calculation of RCIs show agreement on whether or not a reliable change was observed. CONCLUSIONS: RCIs for the digital tests enable clinicians to determine whether a measured change between assessments is due to real improvement or decline. Together, this contributes to the growing evidence for the clinical utility of the ISC platform.

Evidence of Validity for a Newly Developed Digital Cognitive Test Battery.

Clinical practice still relies heavily on traditional paper-and-pencil testing to assess a patient's cognitive functions. Digital technology has the potential to be an efficient and powerful alternative, but for many of the existing digital tests and test batteries the psychometric properties have not been properly established. We validated a newly developed digital test battery consisting of digitized versions of conventional neuropsychological tests. Two confirmatory factor analysis models were specified: a model based on traditional neuropsychological theory and expert consensus and one based on the Cattell-Horn-Carroll (CHC) taxonomy. For both models, the outcome measures of the digital tests loaded on the cognitive domains in the same way as established in the neuropsychological literature. Interestingly, no clear distinction could be made between the CHC model and traditional neuropsychological model in terms of model fit. Taken together, these findings provide preliminary evidence for the structural validity of the digital cognitive test battery.

Non-dominant hand use increases completion time on part B of the Trail Making Test but not on part A.

The Trail Making Test (TMT) is used in neuropsychological clinical practice to assess aspects of attention and executive function. The test consists of two parts (A and B) and requires drawing a trail between elements. Many patients are assessed with their non-dominant hand because of motor dysfunction that prevents them from using their dominant hand. Since drawing with the non-dominant hand is not an automatic task for many people, we explored the effect of hand use on TMT performance. The TMT was administered digitally in order to analyze new outcome measures in addition to total completion time. In a sample of 82 healthy participants, we found that non-dominant hand use increased completion times on the TMT B but not on the TMT A. The average completion time increased by almost 5 seconds, which may be clinically relevant. A substantial number of participants who performed the TMT with their non-dominant hand had a B/A ratio score of 2.5 or higher. In clinical practice, an abnormally high B/A ratio score may be falsely attributed to cognitive dysfunction. With our digitized pen data, we further explored the causes of the reduced TMT B performance by using new outcome measures, including individual element completion times and interelement variability. These measures indicated selective interference between non-dominant hand use and executive functions. Both non-dominant hand use and performance of the TMT B seem to draw on the same, limited higher-order cognitive resources.

Objective measurement of gait parameters in healthy and cognitively impaired elderly using the dual-task paradigm.

OBJECTIVES: The present study explores the differences in gait parameters in elderly subjects with or without cognitive impairment measured by means of ambulatory actigraphy while performing a single and a dual task. METHODS: Sixty-nine participants of which 23 individuals were diagnosed with Alzheimer's disease (AD), 24 individuals with mild cognitive impairment (MCI), and 22 healthy controls performed a single and dual walking task while wearing a wrist-worn accelerometer. Objective measures of gait features such as walking speed, cadence (i.e., number of steps per minute), and step variance (i.e., variance in time between two consecutive steps) were derived and analyzed. RESULTS: While differences in several gait parameters, namely walking speed, were found between MCI and AD patients, no differences between healthy elderly and MCI patients were found. CONCLUSION: Walking speed seems to be a gait-related feature that differs significantly between MCI and AD patients and thus could be used as an additional measurement in clinical assessment. However, differences in gait may not be salient enough in the early stages of dementia to be detected by actigraphy. More research comparing different methods to measure gait in early stages of dementia under different dual task conditions is neccessary.

The Relation Between Anticipatory Anxiety and Movement During an MR Examination.

RATIONALE AND OBJECTIVES: During a magnetic resonance imaging (MRI) examination, patients are required to remain still to minimize motion that may compromise image quality and may make rescanning necessary. It is often assumed that anxiety, which is experienced by a considerable number of patients undergoing an MR examination, increases motion and decreases image quality. The present study explores the relationship between anxiety and movement of patients during an MR examination. MATERIALS AND METHODS: Anxiety was measured subjectively by means of the State Anxiety Inventory and a visual analogue scale for claustrophobia. Motion and image quality were measured in three different ways. First, software was used that allows an estimation of motion based on tracker scans between the clinical scans. Second, the MRI technician who performed the MR examination was asked to indicate the degree of motion artifacts and image quality for each patient. Third, after all scans had been collected, two radiologists evaluated each clinical scan. RESULTS: No or low correlations between anxiety and the distinct measures of motion and image quality were found for all three measures. CONCLUSIONS: This finding shows that there is little evidence for the assumption that anxiety increases motion and decreases image quality during an MR examination.

Pinpointing moments of high anxiety during an MRI examination.

BACKGROUND: Magnetic Resonance Imaging (MRI) is associated with high levels of anxiety in many patients which may interfere with image quality and increase examination time. In order to develop effective intervention strategies that decrease anxiety, more insights into moments of high anxiety during a MRI examination are necessary. PURPOSE: The present study aimed at obtaining insights into anxiety levels and moments of high anxiety during a Magnetic Resonance Imaging examination. METHOD: The study included 67 patients, of whom 52 (77.6 %) were categorized as highly anxious. Stress and anxiety were measured continuously throughout the entire duration of the MRI examination by monitoring the heart rate. An increase in heart rate during the scan was taken as an indication for higher stress and anxiety. In addition to measuring stress and anxiety objectively, anxiety was assessed subjectively before and after the procedure by means of self-report questionnaires. RESULTS: The self-report data indicate that patients were highly anxious before the MRI examination. Moreover, the electrophysiological data clearly show that anxiety levels were highest at the beginning of the procedure, i.e., when the MRI table moved into the scanner, and then decreased over the course of the examination. Furthermore, the findings show that while subjectively measured anxiety was higher in patients who had taken anxiolytics prior to the MRI examination than in patients who had not taken any anxiolytics, objectively measured anxiety during the scan was equally high in both groups. CONCLUSION: The present study provides detailed insights into the anxiety levels during an MRI examination, which may aid in developing effective anxiety-reduction strategies. Additionally, the findings show that measuring anxiety continuously throughout the entire examination using electrophysiology in combination with measuring anxiety subjectively prior to and after the scan provides a more complete assessment of MRI-related anxiety.

Did My Brain Implant Make Me Do It? Questions Raised by DBS Regarding Psychological Continuity, Responsibility for Action and Mental Competence.

Deep brain stimulation (DBS) is a well-accepted treatment for movement disorders and is currently explored as a treatment option for various neurological and psychiatric disorders. Several case studies suggest that DBS may, in some patients, influence mental states critical to personality to such an extent that it affects an individual's personal identity, i.e. the experience of psychological continuity, of persisting through time as the same person. Without questioning the usefulness of DBS as a treatment option for various serious and treatment refractory conditions, the potential of disruptions of psychological continuity raises a number of ethical and legal questions. An important question is that of legal responsibility if DBS induced changes in a patient's personality result in damage caused by undesirable or even deviant behavior. Disruptions in psychological continuity can in some cases also have an effect on an individual's mental competence. This capacity is necessary in order to obtain informed consent to start, continue or stop treatment, and it is therefore not only important from an ethical point of view but also has legal consequences. Taking the existing literature and the Dutch legal system as a starting point, the present paper discusses the implications of DBS induced disruptions in psychological continuity for a patient's responsibility for action and competence of decision and raises a number of questions that need further research.