Faculty Bibliography

The senses of taste and smell developed early in evolution and are of high ecological and clinical relevance in humans. Chemosensory systems function, in large part, as hazard avoidance systems, thereby ensuring survival. Moreover, they play a critical role in nutrition and in determining the flavor of foods and beverages. Their dysfunction has been shown to be a key element of early stages of a number of diseases, including Alzheimer's and Parkinson's diseases. Advanced neuroimaging methods provide a unique means for understanding, in vivo, neural and psychological processing of smell, taste, and flavor, and how diseases can impact such processing. This chapter provides, from a neuroimaging perspective, a comprehensive overview of the anatomy and physiology involved in the odor and taste processing in the central nervous system. Some methodological challenges associated with chemosensory neuroimaging research are discussed. Multisensory integration, the mechanisms that enable holistic sensory experiences, is emphasized.

Background: Symptoms related to impaired visuospatial function are relatively common in patients with Parkinson's disease (PD). Restricted visual processing can directly hamper patients' motor function. For example, systematic biases in visual perception may influence navigational veering, thus directly affecting locomotion. In patients with PD, an impaired visual function is linked to negative feelings including depression, fearfulness and reduced self-efficacy. Art Therapy (AT) has the potential of recruiting different neural networks, including those concerned with high visual conscious perception. As such, AT may serve as a neurobehavioral intervention to improve multiple functional domains, including visuospatial functions and emotional wellness.
Method(s): This is a dual-phase exploratory study. 1: cross-sectional, controlled, biomarker study on 30 non-demented PD patients (H&Y 2-3) and 30 age-matched controls; 2: prospective, open label study involving 20 sessions of AT (2sessions/week). Motor and gait functions were assessed by MDS-UPDRS, Timed Up and Go test (TUG), and wearable accelerometers. Cognitive and Visuospatial functions were assessed by neuropsychological inventories (MoCA, Rey-Osterrieth FigureTest, Benton Visual Test), computerized testing (Navon VisualTest, Visual Research Test, and visual reaction time), and binocular eyetracking (Eyelink 2). Psychological wellness was assessed by Beck Depression Index (BDI), Modified Fatigue Impact Scale, and PROMIS-Self-Efficacy scales. Brain imaging included T1-weighted 3D high resolution, DWI, and RSfMRI sequences. Preliminary analyses were conducted on clinical data from 18 PD-patients and 14 controls completing the study. Eye tracking from 4 subjects was analyzed for exploratory purposes.
Result(s): PD-patients and controls were significantly different with respect to BDI score, Navon Visual Test, Rey Figure Test, UPDRSIII, and TUG-3 (maximum gait speed). Following AT, PD patients showed significant improvements in UPDRS-III, UPDRS-total, PROMIS (symptoms management), and Navon Visual Test (number of errors). A strong trend towards improved ReyeFigureTest was observed. On eye tracking analysis, significant increases in exploratory eye movements and fixation patterns were observed spatiotopically during examined stimulus regions.
Discussion(s): According to our preliminary findings, AT may improve visual-constructional abilities, visual recognition, and motor function. These improvements are accompanied by increased self-efficacy and changes in oculomotor behavior characterized by a more efficient visual exploration strategy. The duration of these potential benefits as well as their underlying mechanisms remain to be determined

Background: Fatigue is one of the most prevalent and underassessed non-motor symptoms in PD. Transcranial direct current stimulation (tDCS) is a portable non-invasive brain stimulation device that utilizes low current to alter brain activity. We designed a tele-monitored tDCS (tele-tDCS) protocol to assess feasibility, safety and explore the therapeutic potential of tele-tDCS for Parkinson's disease (PD) related fatigue. We utilized a live videoconferencing platform and specifically designed equipment.
Method(s): Preliminary analysis of eighteen PD patients, age 35-89 that participated in a double-blind, randomized, sham-controlled study. Each participant completed 10 tDCS sessions (20-minute, 2.0-mA, bi-frontal DLPFC montage, left anodal), over a span of two weeks. After completion, 10 additional open-label sessions were offered. Tolerability, safety, and compliance were evaluated. Preliminary clinical effects were measured with the Fatigue Severity Scale (FSS).
Result(s): Seventeen participants completed 330 tele-tDCS sessions; one subject chose not to complete the 10 optional sessions. Tolerability of 2.0 mA stimulation with = 6 on the Visual Analog Scale for Pain (VAS-Pain) was 100%. Systematically recorded side effects were comparable with previously published studies using conventional tDCS (in-lab). No serious adverse events were reported. Compliance was 100% as subjects completed all required visits with no attrition or interruptions. Preliminary fatigue clinical effects of 10 sessions showed a significant decrease of FSS only in real-tDCS (mean 16% decrease in FSS, p=0.05); however, there was no significant difference between groups. Further analysis of 20 real-tDCS sessions in nine subjects showed a further decrease in FSS (mean 27%; p=0.013).
Conclusion(s): At-home tele-tDCS therapy is safe and well tolerated by PD patients, with the advantages of ease of recruitment and subject compliance. Acceptability was achieved by easy setup and intuitive design of the device. At-home tele-tDCS therapy shows potential to remediate fatigue symptoms in PD, especially after 20 sessions. The small sample size limits efficacy conclusions. Our paradigm may be influential in designing future studies that will facilitate clinical trials with a larger subject population and extended trial duration. (Figure Presented)

Hutson and Vexler (2018) demonstrate an example of aliasing with the beta and normal distribution. This letter presents another illustration of aliasing using the beta and normal distributions via an infinite mixture model, inspired by the problem of modeling placebo response.