PsychoPy is an application for the creation of experiments in behavioral science (psychology, neuroscience, linguistics, etc.) with precise spatial control and timing of stimuli. It now provides a choice of interface; users can write scripts in Python if they choose, while those who prefer to construct experiments graphically can use the new Builder interface. Here we describe the features that have been added over the last 10 years of its development. The most notable addition has been that Builder interface, allowing users to create studies with minimal or no programming, while also allowing the insertion of Python code for maximal flexibility. We also present some of the other new features, including further stimulus options, asynchronous time-stamped hardware polling, and better support for open science and reproducibility. Tens of thousands of users now launch PsychoPy every month, and more than 90 people have contributed to the code. We discuss the current state of the project, as well as plans for the future.

The MoCA is a suitably accurate, brief test when screening all levels of cognition in PD.

Many researchers in the behavioral sciences depend on research software that presents stimuli, and records response times, with sub-millisecond precision. There are a large number of software packages with which to conduct these behavioral experiments and measure response times and performance of participants. Very little information is available, however, on what timing performance they achieve in practice. Here we report a wide-ranging study looking at the precision and accuracy of visual and auditory stimulus timing and response times, measured with a Black Box Toolkit. We compared a range of popular packages: PsychoPy, E-Prime®, NBS Presentation®, Psychophysics Toolbox, OpenSesame, Expyriment, Gorilla, jsPsych, Lab.js and Testable. Where possible, the packages were tested on Windows, macOS, and Ubuntu, and in a range of browsers for the online studies, to try to identify common patterns in performance. Among the lab-based experiments, Psychtoolbox, PsychoPy, Presentation and E-Prime provided the best timing, all with mean precision under 1 millisecond across the visual, audio and response measures. OpenSesame had slightly less precision across the board, but most notably in audio stimuli and Expyriment had rather poor precision. Across operating systems, the pattern was that precision was generally very slightly better under Ubuntu than Windows, and that macOS was the worst, at least for visual stimuli, for all packages. Online studies did not deliver the same level of precision as lab-based systems, with slightly more variability in all measurements. That said, PsychoPy and Gorilla, broadly the best performers, were achieving very close to millisecond precision on several browser/operating system combinations. For response times (measured using a high-performance button box), most of the packages achieved precision at least under 10 ms in all browsers, with PsychoPy achieving a precision under 3.5 ms in all. There was considerable variability between OS/browser combinations, especially in audio-visual synchrony which is the least precise aspect of the browser-based experiments. Nonetheless, the data indicate that online methods can be suitable for a wide range of studies, with due thought about the sources of variability that result. The results, from over 110,000 trials, highlight the wide range of timing qualities that can occur even in these dedicated software packages for the task. We stress the importance of scientists making their own timing validation measurements for their own stimuli and computer configuration.

The neural pathways and brain regions involved in eye movements during ocular fixation and gaze control include the cerebrum, brainstem and cerebellum, and abnormal eye movements can indicate the presence of neurodegeneration. In some patients, oculomotor signs are key to making a diagnosis. Careful clinical examination of eye movements in patients with neurodegenerative disorders is, therefore, an invaluable adjunct to neurological and cognitive assessments. Eye movement recordings in the laboratory are generally not necessary for diagnostic purposes, but can be a useful addition to the clinical examination. Laboratory recordings of eye movements can provide valuable information about disease severity, progression or regression in neurodegenerative disease, and hold particular promise for objective evaluation of the efficacy of putative neuroprotective and neurorestorative therapies. For example, aspects of saccade performance can be tested to probe both motor and cognitive aspects of oculomotor behaviour. This Review describes the oculomotor features of the major age-related movement disorders, including Parkinson disease, Huntington disease, dementia and other neurodegenerative disorders. Findings in presymptomatic individuals and changes associated with disease progression are discussed.

Marked grey matter atrophy occurs in PD with dementia but far less extensive changes are evident in PD-MCI. Some grey matter atrophy precedes the development of dementia but may be accelerated once frank dementia begins.

There is a need for objective imaging markers of Parkinson's disease status and progression. Positron emission tomography and single photon emission computed tomography studies have suggested patterns of abnormal cerebral perfusion in Parkinson's disease as potential functional biomarkers. This study aimed to identify an arterial spin labelling magnetic resonance-derived perfusion network as an accessible, non-invasive alternative. We used pseudo-continuous arterial spin labelling to measure cerebral grey matter perfusion in 61 subjects with Parkinson's disease with a range of motor and cognitive impairment, including patients with dementia and 29 age- and sex-matched controls. Principal component analysis was used to derive a Parkinson's disease-related perfusion network via logistic regression. Region of interest analysis of absolute perfusion values revealed that the Parkinson's disease pattern was characterized by decreased perfusion in posterior parieto-occipital cortex, precuneus and cuneus, and middle frontal gyri compared with healthy controls. Perfusion was preserved in globus pallidus, putamen, anterior cingulate and post- and pre-central gyri. Both motor and cognitive statuses were significant factors related to network score. A network approach, supported by arterial spin labelling-derived absolute perfusion values may provide a readily accessible neuroimaging method to characterize and track progression of both motor and cognitive status in Parkinson's disease.

PD is associated with spatially restricted loss of microstructural white matter integrity in patients with relatively normal cognition, and these alterations increase with cognitive dysfunction. Functional impairment in executive function, attention, and learning and memory appears associated with microstructural changes, suggesting that tract-based spatial statistics provides an early marker for clinically relevant cognitive impairment in PD.

There is growing interest in identifying Parkinson's disease (PD) patients with mild cognitive impairment (PD-MCI), but widely disparate criteria have been used. We assessed 143 PD patients and 50 matched controls on 20 measures across 4 cognitive domains (executive function, attention and working memory, learning and memory, visuoperception). Twenty-four patients met criteria for dementia (PD-D); nondementia patients were classified as either with normal cognition or MCI for 12 neuropsychological criteria. We compared the influence of these criteria on the distribution of global cognitive performance in the resulting PD-MCI groups relative to the control and PD-D groups. Different criteria produced substantial variation in the proportion of PD-MCI cases identified. Fourteen percent PD-MCI was found when using 2 scores in 1 domain at 2 standard deviations (SD) below normative scores, with no controls identified as MCI, through to 89% PD-MCI with 1 score in 1 domain at 1 SD below normative scores, when 70% of controls were identified as MCI. The balance of cases with impaired cognition but not those with generally intact cognition was better served by using criteria that required 2 specific deficit scores or deficits across 2 domains. As comparisons with external normative data may have greater applicability across centers, we suggest that 2 scores at -1.5 SD within any single domain (30% PD-MCI) or 1 score at -1.5 SD in each of 2 domains (37% PD-MCI) provide suitable criteria to minimize the inclusion of cognitively well patients. Clinical dementia rating did not improve the relative identification of cognitively impaired and unimpaired nondementia PD patients.