How we perceive the width of grasped objects: Insights into the central processes that govern proprioceptive judgements.

Low-level proprioceptive judgements involve a single frame of reference, whereas high-level proprioceptive judgements are made across different frames of reference. The present study systematically compared low-level (grasp → $\rightarrow$ grasp) and high-level (vision → $\rightarrow$ grasp, grasp → $\rightarrow$ vision) proprioceptive tasks, and quantified the consistency of grasp → $\rightarrow$ vision and possible reciprocal nature of related high-level proprioceptive tasks. Experiment 1 (n = 30) compared performance across vision → $\rightarrow$ grasp, a grasp → $\rightarrow$ vision and a grasp → $\rightarrow$ grasp tasks. Experiment 2 (n = 30) compared performance on the grasp → $\rightarrow$ vision task between hands and over time. Participants were accurate (mean absolute error 0.27 cm [0.20 to 0.34]; mean [95% CI]) and precise ( R 2 $R^2$ = 0.95 [0.93 to 0.96]) for grasp → $\rightarrow$ grasp judgements, with a strong correlation between outcomes (r = -0.85 [-0.93 to -0.70]). Accuracy and precision decreased in the two high-level tasks ( R 2 $R^2$ = 0.86 and 0.89; mean absolute error = 1.34 and 1.41 cm), with most participants overestimating perceived width for the vision → $\rightarrow$ grasp task and underestimating it for grasp → $\rightarrow$ vision task. There was minimal correlation between accuracy and precision for these two tasks. Converging evidence indicated performance was largely reciprocal (inverse) between the vision → $\rightarrow$ grasp and grasp → $\rightarrow$ vision tasks. Performance on the grasp → $\rightarrow$ vision task was consistent between dominant and non-dominant hands, and across repeated sessions a day or week apart. Overall, there are fundamental differences between low- and high-level proprioceptive judgements that reflect fundamental differences in the cortical processes that underpin these perceptions. Moreover, the central transformations that govern high-level proprioceptive judgements of grasp are personalised, stable and reciprocal for reciprocal tasks. KEY POINTS: Low-level proprioceptive judgements involve a single frame of reference (e.g. indicating the width of a grasped object by selecting from a series of objects of different width), whereas high-level proprioceptive judgements are made across different frames of reference (e.g. indicating the width of a grasped object by selecting from a series of visible lines of different length). We highlight fundamental differences in the precision and accuracy of low- and high-level proprioceptive judgements. We provide converging evidence that the neural transformations between frames of reference that govern high-level proprioceptive judgements of grasp are personalised, stable and reciprocal for reciprocal tasks. This stability is likely key to precise judgements and accurate predictions in high-level proprioception.

Encouraging responsible reporting practices in the Instructions to Authors of neuroscience and physiology journals: There is room to improve.

Journals can substantially influence the quality of research reports by including responsible reporting practices in their Instructions to Authors. We assessed the extent to which 100 journals in neuroscience and physiology required authors to report methods and results in a rigorous and transparent way. For each journal, Instructions to Authors and any referenced reporting guideline or checklist were downloaded from journal websites. Twenty-two questions were developed to assess how journal Instructions to Authors address fundamental aspects of rigor and transparency in five key reporting areas. Journal Instructions to Authors and all referenced external guidelines and checklists were audited against these 22 questions. Of the full sample of 100 Instructions to Authors, 34 did not reference any external reporting guideline or checklist. Reporting whether clinical trial protocols were pre-registered was required by 49 journals and encouraged by 7 others. Making data publicly available was encouraged by 64 journals; making (processing or statistical) code publicly available was encouraged by ∼30 of the journals. Other responsible reporting practices were mentioned by less than 20 of the journals. Journals can improve the quality of research reports by mandating, or at least encouraging, the responsible reporting practices highlighted here.

Upper Limb Function but Not Proprioception is Impaired in Essential Tremor: A Between-Groups Study and Causal Mediation Analysis.

Background: Essential tremor (ET) is characterized by abnormal oscillatory muscle activity and cerebellar involvement, factors that can lead to proprioceptive deficits, especially in active tasks. The present study aimed to quantify the severity of proprioceptive deficits in people with ET and estimate how these contribute to functional impairments. Methods: Upper limb sensory, proprioceptive and motor function was assessed inindividuals with ET (n = 20) and healthy individuals (n = 22). To measure proprioceptive ability, participants discriminated the width of grasped objects and the weight of objects liftedwith the wrist extensors. Causal mediation analysis was used to estimate the extentthat impairments in upper limb function in ET was mediated by proprioceptive ability. Results: Participants with ET had impaired upper limb function in all outcomes, and had greater postural and kinetic tremor. There were no differences between groups in proprioceptive discrimination of width (between-group mean difference [95% CI]: 0.32 mm [-0.23 to 0.87 mm]) or weight (-1.12 g [-7.31 to 5.07 g]). Causal mediation analysis showed the effect of ET on upper limb function was not mediated by proprioceptive ability. Conclusions: Upper limb function but not proprioception was impaired in ET. The effect of ET on motor function was not mediated by proprioception. These results indicate that the central nervous system of people with ET is able to accommodate mild to moderate tremor in active proprioceptive tasks that rely primarily on afferent signals from muscle spindles.

Use of a physiological profile to document upper limb motor impairment in ageing and in neurological conditions.

Profiling performance in the physiological domains underpinning upper limb function (such as strength, sensation, coordination) provides insight into an individual's specific impairments. This compliments the traditional medical 'diagnosis' model that is currently used in contemporary medicine. From an initial battery of 13 tests in which data were collected across the adult lifespan (n = 367, 20-95 years) and in those with neurological conditions (specifically, multiple sclerosis (n = 40), Parkinson's disease (n = 34), and stroke (n = 50)), six tests were selected to comprise a core upper limb physiological profile assessment (PPA). This comprised measures of handgrip strength, simple reaction time, finger dexterity, tactile sensation, bimanual coordination, and a functional task. Individual performance in each of these tests can be compared to a reference population score (devised from our database of healthy individuals aged under 60 years), informing the researcher or clinician how to best direct an intervention or treatment for the individual based on their specific impairment(s). Lastly, a composite score calculated from the average performance across the six tests provides a broad overview of an individual's overall upper limb function. Collectively, the upper limb PPA highlights specific impairments that are prevalent within distinct pathologies and reveals the magnitude of upper limb motor impairment specific to each condition.

Poor statistical reporting, inadequate data presentation and spin persist despite Journal awareness and updated Information for Authors.

Sound reporting of research results is fundamental to good science. Unfortunately, poor reporting is common and does not improve with editorial educational strategies. We investigated whether publicly highlighting poor reporting at a journal can lead to improved reporting practices. We also investigated whether reporting practices that are required or strongly encouraged in journal Information for Authors are enforced by journal editors and staff. A 2016 audit highlighted poor reporting practices in the Journal of Neurophysiology. In August 2016 and 2018, the American Physiological Society updated the Information for Authors, which included the introduction of several required or strongly encouraged reporting practices. We audited Journal of Neurophysiology papers published in 2019 and 2020 (downloaded through the library of the University of New South Wales) on reporting items selected from the 2016 audit, the newly introduced reporting practices, and items from previous audits. Summary statistics (means, counts) were used to summarize audit results. In total, 580 papers were audited. Compared to results from the 2016 audit, several reporting practices remained unchanged or worsened. For example, 60% of papers erroneously reported standard errors of the mean, 23% of papers included undefined measures of variability, 40% of papers failed to define a statistical threshold for their tests, and when present, 64% of papers with p-values between 0.05 and 0.1 misinterpreted them as statistical trends. As for the newly introduced reporting practices, required practices were consistently adhered to by 34 to 37% of papers, while strongly encouraged practices were consistently adhered to by 9 to 26% of papers. Adherence to the other audited reporting practices was comparable to our previous audits. Publicly highlighting poor reporting practices did little to improve research reporting. Similarly, requiring or strongly encouraging reporting practices was only partly effective. Although the present audit focused on a single journal, this is likely not an isolated case. Stronger, more strategic measures are required to improve poor research reporting.

Quality Output Checklist and Content Assessment (QuOCCA): a new tool for assessing research quality and reproducibility.

Research must be well designed, properly conducted and clearly and transparently reported. Our independent medical research institute wanted a simple, generic tool to assess the quality of the research conducted by its researchers, with the goal of identifying areas that could be improved through targeted educational activities. Unfortunately, none was available, thus we devised our own. Here, we report development of the Quality Output Checklist and Content Assessment (QuOCCA), and its application to publications from our institute's scientists. Following consensus meetings and external review by statistical and methodological experts, 11 items were selected for the final version of the QuOCCA: research transparency (items 1-3), research design and analysis (items 4-6) and research reporting practices (items 7-11). Five pairs of raters assessed all 231 articles published in 2017 and 221 in 2018 by researchers at our institute. Overall, the results were similar between years and revealed limited engagement with several recommended practices highlighted in the QuOCCA. These results will be useful to guide educational initiatives and their effectiveness. The QuOCCA is brief and focuses on broadly applicable and relevant concepts to open, high-quality, reproducible and well-reported science. Thus, the QuOCCA could be used by other biomedical institutions and individual researchers to evaluate research publications, assess changes in research practice over time and guide the discussion about high-quality, open science. Given its generic nature, the QuOCCA may also be useful in other research disciplines.

Putting People First: The Importance of Recommending Minimum Staffing Levels and Skills Mix.

Australia's Royal Commission into Aged Care Quality and Safety has concluded. The Commission's final report described a sector failing to deliver care that older Australians deserve despite the best efforts of many staff. Throughout the Commission, staffing was a frequent concern, with the size and composition of the direct care workforce a prominent focus. Throughout the Commission, many stakeholders campaigned for mandated staffing levels in skills mix in nursing homes and the Commission's report and Commonwealth Government response included recommendations for these. While this is a necessary step toward wider reform, the Royal Commission's recommendation and the Australian Government's response must support the delivery of best practice care more strongly. This column argues that the minimum standard for nursing home staff care time must be higher, and that higher minimum staffing levels and more clearly defined skills mix are critical to the delivery of safe, respectful, dignified person-centred care.

Proprioception: a new look at an old concept.

Proprioception, which can be defined as the awareness of the mechanical and spatial state of the body and its musculoskeletal parts, is critical to motor actions and contributes to our sense of body ownership. To date, clinical proprioceptive tests have focused on a person's ability to detect, discriminate, or match limb positions or movements, and reveal that the strength of the relationship between deficits in proprioception and physical function varies widely. Unfortunately, these tests fail to assess higher-level proprioceptive abilities. In this Perspective, we propose that to understand fully the link between proprioception and function, we need to look beyond traditional clinical tests of proprioception. Specifically, we present a novel framework for human proprioception assessment that is divided into two categories: low-level and high-level proprioceptive judgments. Low-level judgments are those made in a single frame of reference and are the types of judgments made in traditional proprioceptive tests (i.e., detect, discriminate or match). High-level proprioceptive abilities involve proprioceptive judgments made in a different frame of reference. For example, when a person indicates where their hand is located in space. This framework acknowledges that proprioception is complex and multifaceted and that tests of proprioception should not be viewed as interchangeable, but rather as complimentary. Crucially, it provides structure to the way researchers and clinicians can approach proprioception and its assessment. We hope this Perspective serves as the catalyst for discussion and new lines of investigation.

Quantifying upper-limb motor impairment in people with multiple sclerosis: A physiological profiling approach.

BACKGROUND: . Upper-limb sensory and motor impairments are common in people with multiple sclerosis (MS), yet the current gold standard criteria for documenting functional impairment largely focuses on mobility, balance and postural stability. OBJECTIVE: . We aimed to determine the validity of the upper-limb Physiological Profile Assessment (PPA) in people with MS by investigating whether the included domains of muscle strength, dexterity, arm stability, position sense, skin sensation and bimanual coordination 1) are sensitive in differentiating people with MS from healthy controls and 2) correlate with a validated measure of upper-limb function and a scale for quantifying disability in MS. METHODS: . In a cross-sectional study, 40 participants with MS and 80 healthy controls completed all 13 of the upper-limb PPA tests within a single session. RESULTS: . People with MS were impaired across all physiological domains tested. Performance in 4 of the 13 tests was correlated with a validated measure of self-reported upper-limb function (Pearson's r or Spearman's rho -0.333-0.441), whereas 3 tests were associated with the degree of MS-specific disability (Spearman's rho -0.318; 0.456). CONCLUSIONS: . The upper-limb PPA offers a valid and clinically suitable assessment of upper-limb function in people with MS. Clinicians should prioritize assessments of motor speed, fine motor control and functional tasks in their assessment of upper-limb function in people with MS because these domains are the most commonly and significantly impaired.

Royal Commission into Aged Care recommendations on minimum staff time standard for nursing homes.

The Royal Commission's recommendation for nursing home minimum time standards and the Australian Government's response do not support best practice resident care. We recommend that higher mandated minimum staffing levels and skills mix should be phased in by mid-2026. What is known about the topic? The Australian Government has not committed to fully implementing the Commission's recommendations for mandated minimum staff time standards. What does this paper add? We highlight issues with the Commission's recommendations and the Australian Government's response where they do not support sufficient minimum time to provide best practice care. What are the implications for practitioners? Mandated evidence-based minimum staffing levels and skills mix should be phased in by mid-2026 to support best practice care.

Do interoception and attending to the upper limbs affect body ownership and body representation in the grasp illusion?

Passively grasping an unseen artificial finger induces ownership over this finger and an illusory coming together of one's index fingers: a grasp illusion. Here we determine how interoceptive ability and attending to the upper limbs influence this illusion. Participants passively grasped an unseen artificial finger with their left index finger and thumb for 3 min while their right index finger, located 12 cm below, was lightly clamped. Experiment 1 (n = 30) investigated whether the strength of the grasp illusion (perceived index finger spacing and perceived ownership) is related to a person's level of interoceptive accuracy (modified heartbeat counting task) and sensibility (Noticing subscale of the Multidimensional Assessment of Interoceptive Awareness). Experiment 2 (n = 30) investigated the effect of providing verbal or tactile cues to guide participants' attention to their upper limbs. On their own, neither interoceptive accuracy and sensibility or verbal and tactile cueing had an effect on the grasp illusion. However, verbal cueing increased the strength of the grasp illusion in individuals with lower interoceptive ability. Across the observed range of interoceptive accuracy and sensibility, verbal cueing decreased perceived index spacing by 5.6 cm [1.91 to 9.38] (mean [95%CI]), and perceived ownership by ∼3 points on a 7-point Likert scale (slope -0.93 [-1.72 to -0.15]). Thus, attending to the upper limbs via verbal cues increases the strength of the grasp illusion in a way that is inversely proportional to a person's level of interoceptive accuracy and sensibility.

Quantifying upper limb motor impairment in chronic stroke: a physiological profiling approach.

Upper limb motor impairments, such as muscle weakness, loss of dexterous movement, and reduced sensation, are common after a stroke. The extent and severity of these impairments differ among individuals, depending on the anatomical location and size of lesions. Identifying impairments specific to the individual is critical to optimize their functional recovery. The upper limb Physiological Profile Assessment (PPA) provides quantitative measures of key physiological domains required for adequate function in the upper limbs. The present study investigates the use of the upper limb PPA in a chronic stroke population. Fifty participants with chronic stroke completed all tests of the upper limb PPA with both their affected and less affected upper limbs. Performance in each test was compared to that of 50 age- and sex-matched control subjects with no history of a stroke. Correlations between test performance and validated measures of stroke, sensorimotor function, and disability were examined. Compared with control subjects, people with stroke demonstrated substantially impaired upper limb PPA performance for both their affected and less affected limbs. Performance in the upper limb PPA was associated with validated measures of sensorimotor function specific to the stroke population (Fugl-Meyer Assessment) and stroke-related disability (Stroke Impact Scale). The upper limb PPA shows good concurrent validity as a means to quantify upper limb function in a chronic stroke population. These tests identify domain-specific deficits and could be further tailored to an individual patient by the clinician to inform rehabilitation and track recovery.NEW & NOTEWORTHY Upper limb motor impairment is a common manifestation after stroke, compromising independence in fundamental daily activities involving the ability to reach, grasp, and manipulate objects. The upper limb Physiological Profile Assessment (PPA) offers a means of quantifying performance of the individual sensorimotor domains that are essential for upper limb function. Establishing individual performance profiles based on age- and sex-based normative scores may facilitate individualized treatment decisions by identifying the stroke patient's specific strengths and limitations.

Delivering, funding, and rating safe staffing levels and skills mix in aged care.

BACKGROUND: Staffing levels and skill mix are critical issues within residential aged care. The positive impact of a sufficient number and skills mix of staff is upheld by abundant evidence within and beyond the sector. While being able to determine suitable staffing levels and skills mix to provide care to nursing home residents is vital, having an appropriate approach to funding the delivery of care is also critical. Beyond determining staffing levels and skills mix and funding care delivery, transparently rating the adequacy of staffing is also important to enable informed decision-making amongst consumers, policy makers, staff, and other stakeholders. There are existing tools for determining nursing home staffing levels and skills mix, funding care, and rating and reporting staffing, however there appears to be ongoing confusion regarding how these different tools might work together to achieve different things in order to ensure safe, quality care. OBJECTIVES: In order to explain the importance of ensuring at least a minimum number (staffing level) of the right kind of staff (skills mix) to provide care to nursing home residents, in this paper we briefly explain key differences and interrelationships between three tools; one for determining staffing and skills mix, one for determining funding, and one for rating and reporting the level of staffing within a facility as a measure of quality. RESULTS: Our explanation of the three existing tools has resulted in the development of a conceptual model for how minimum staffing levels and skills mix supports the delivery of safe, quality care and how this can be understood in relation to determining, funding, and rating staffing levels and skills mix. CONCLUSIONS: Our conceptual model of how determining, funding, and rating staffing levels and skills mix relate to one another and fulfil different but related purposes can be used to demonstrate how minimum staffing levels and skills mix can be understood as foundational to ensuring respectful, safe, quality care.

Quantifying upper limb motor impairment in people with Parkinson's disease: a physiological profiling approach.

BACKGROUND: Upper limb motor impairments, such as slowness of movement and difficulties executing sequential tasks, are common in people with Parkinson's disease (PD). OBJECTIVE: To evaluate the validity of the upper limb Physiological Profile Assessment (PPA) as a standard clinical assessment battery in people with PD, by determining whether the tests, which encompass muscle strength, dexterity, arm stability, position sense, skin sensation and bimanual coordination can (a) distinguish people with PD from healthy controls, (b) detect differences in upper limb test domains between "off" and "on" anti-Parkinson medication states and (c) correlate with a validated measure of upper limb function. METHODS: Thirty-four participants with PD and 68 healthy controls completed the upper limb PPA tests within a single session. RESULTS: People with PD exhibited impaired performance across most test domains. Based on validity, reliability and feasibility, six tests (handgrip strength, finger-press reaction time, 9-hole peg test, bimanual pole test, arm stability, and shirt buttoning) were identified as key tests for the assessment of upper limb function in people with PD. CONCLUSIONS: The upper limb PPA provides a valid, quick and simple means of quantifying specific upper limb impairments in people with PD. These findings indicate clinical assessments should prioritise tests of muscle strength, unilateral movement and dexterity, bimanual coordination, arm stability and functional tasks in people with PD as these domains are the most commonly and significantly impaired.

Judgements of hand location and hand spacing show minimal proprioceptive drift.

With a visual memory of where our hands are, their perceived location drifts. We investigated whether the perceived location of one hand or the spacing between two hands drifts in the absence of visual memories or cues. In 30 participants (17 females, mean age 27 years, range 20-45 years), perceived location of the right index finger was assessed when it was 10 cm to the right or left of the midline. Perceived spacing between the index fingers was assessed when they were spaced 20 cm apart, centred on the midline. Testing included two conditions, one with ten measures at 30 s intervals and another where a 3 min delay was introduced after the fifth measure. Participants responded by selecting a point on a ruler or a line from a series of lines of different lengths. Overall, participants mislocalised their hands closer to the midline. However, there was little to no drift in perceived index finger location when measures were taken at regular intervals (ipsilateral slope: 0.073 cm/measure [[Formula: see text] to 0.160], mean [99% CI]; contralateral slope: 0.045 cm/measure [[Formula: see text] to 0.120]), or across a 3 min delay (ipsilateral: ([Formula: see text] cm [[Formula: see text] to 0.17]; contralateral: [Formula: see text] cm [[Formula: see text] to 0.24]). There was a slight drift in perceived spacing when measures were taken at regular intervals (slope: [Formula: see text] cm/measure [[Formula: see text] to [Formula: see text]]), but none across a 3 min delay (0.08 cm [[Formula: see text] to 1.24]). Thus, proprioceptive-based perceptions of where our hands are located or how they are spaced drift minimally or not at all, indicating these perceptions are stable.

Stepping in circles: how locomotor signals of rotation adapt over time.

KEY POINTS: While it has been well described that prolonged rotational stepping will adapt the podokinetic sense of rotation, the mechanisms involved are not clearly understood. By studying podokinetic after-rotations following conditioning rotations not previously reported we have shown that slower rotational velocities are more readily adapted than faster velocities and adaptation occurs more quickly than previously thought. We propose a dynamic feedback model of vestibular and podokinetic adaptation that can fit rotation trajectories across multiple conditions and data sets. Two adaptation processes were identified that may reflect central and peripheral processes and the discussion unifies prior findings in the podokinetic literature under this new framework. The findings show the technique is feasible for people with locomotor turning problems. ABSTRACT: After a prolonged period stepping in circles, people walk with a curved trajectory when attempting to walk in a straight line without vision. Podokinetic adaptation shows promise in clinical populations to improve locomotor turning; however, the adaptive mechanisms involved are poorly understood. The first phase of this study asks: how does the podokinetic conditioning velocity affect the response velocity and how quickly can adaptation occur? The second phase of the study asks: can a mathematical feedback model account for the rotation trajectories across different conditioning parameters and different datasets? Twelve healthy participants stepped in place on the axis of a rotating surface ranging from 4 to 20 deg s-1 for durations of 1-10 min, while using visual cues to maintain a constant heading direction. Afterward on solid ground, participants were blindfolded and attempted to step without rotating. Participants unknowingly stepped in circles opposite to the direction of the prior platform rotation for all conditions. The angular velocity of this response peaked within 1 min and the ratio of the stimulus-to-response peak velocity fitted a decreasing power function. The response then decayed exponentially. The feedback model of podokinetic and vestibular adaptive processes had a good fit with the data and suggested that podokinetic adaptation is explained by a short (141 s) and a long (27 min) time constant. The podokinetic system adapts more quickly than previously thought and subjects adapt more readily to slower rotation than to faster rotation. These findings will have implications for clinical applications of the technique.