Evidence of heat sensitivity in people with Parkinson's disease.

Examining how heat affects people with Parkinson's disease is essential for informing clinical decision-making, safety, well-being, and healthcare planning. While there is evidence that the neuropathology associated with Parkinson's disease affects thermoregulatory mechanisms, little attention has been given to the association of heat sensitivity to worsening symptoms and restricted daily activities in people with this progressive disease. Using a cross-sectional study design, we examined the experiences of people diagnosed with Parkinson's disease in the heat. Two-hundred and forty-seven people completed an online survey (age: 66.0 ± 9.2 years; sex: male = 102 (41.3%), female = 145 (58.7%)), of which 195 (78.9%) reported becoming more sensitive to heat with Parkinson's disease. Motor and nonmotor symptoms worsened with heat in 182 (73.7%) and 203 (82.2%) respondents, respectively. The most commonly reported symptoms to worsen included walking difficulties, balance impairment, stiffness, tremor, fatigue, sleep disturbances, excess sweating, difficulty concentrating, and light-headedness when standing. Concerningly, over half indicated an inability to work effectively in the heat, and nearly half reported that heat impacted their ability to perform household tasks and social activities. Overall, heat sensitivity was common in people with Parkinson's disease and had a significant impact on symptomology, day-to-day activities and quality of life.

Comparison of Shoulder Range of Motion Quantified with Mobile Phone Video-Based Skeletal Tracking and 3D Motion Capture-Preliminary Study.

BACKGROUND: The accuracy of human pose tracking using smartphone camera (2D-pose) to quantify shoulder range of motion (RoM) is not determined. METHODS: Twenty healthy individuals were recruited and performed shoulder abduction, adduction, flexion, or extension, captured simultaneously using a smartphone-based human pose estimation algorithm (Apple's vision framework) and using a skin marker-based 3D motion capture system. Validity was assessed by comparing the 2D-pose outcomes against a well-established 3D motion capture protocol. In addition, the impact of iPhone positioning was investigated using three smartphones in multiple vertical and horizontal positions. The relationship and validity were analysed using linear mixed models and Bland-Altman analysis. RESULTS: We found that 2D-pose-based shoulder RoM was consistent with 3D motion capture (linear mixed model: R2 > 0.93) but was somewhat overestimated by the smartphone. Differences were dependent on shoulder movement type and RoM amplitude, with adduction the worst performer among all tested movements. All motion types were described using linear equations. Correction methods are provided to correct potential out-of-plane shoulder movements. CONCLUSIONS: Shoulder RoM estimated using a smartphone camera is consistent with 3D motion-capture-derived RoM; however, differences between the systems were observed and are likely explained by differences in thoracic frame definitions.

A Quantum Model of Trust Calibration in Human-AI Interactions.

This exploratory study investigates a human agent's evolving judgements of reliability when interacting with an AI system. Two aims drove this investigation: (1) compare the predictive performance of quantum vs. Markov random walk models regarding human reliability judgements of an AI system and (2) identify a neural correlate of the perturbation of a human agent's judgement of the AI's reliability. As AI becomes more prevalent, it is important to understand how humans trust these technologies and how trust evolves when interacting with them. A mixed-methods experiment was developed for exploring reliability calibration in human-AI interactions. The behavioural data collected were used as a baseline to assess the predictive performance of the quantum and Markov models. We found the quantum model to better predict the evolving reliability ratings than the Markov model. This may be due to the quantum model being more amenable to represent the sometimes pronounced within-subject variability of reliability ratings. Additionally, a clear event-related potential response was found in the electroencephalographic (EEG) data, which is attributed to the expectations of reliability being perturbed. The identification of a trust-related EEG-based measure opens the door to explore how it could be used to adapt the parameters of the quantum model in real time.

Understanding the Sociocognitive Determinants Underlying Intentions to Exercise for Postconcussion Symptom Relief: An Application of the Theory of Planned Behavior.

CONTEXT: This study investigated individual sociocognitive factors from the theory of planned behavior and their relationship to exercise for postconcussion recovery. DESIGN AND METHODS: Four hundred and fifty-nine Australian adults, two-thirds of whom had no concussion history (66%), completed an online survey of their beliefs and attitudes toward exercise for postconcussion recovery. Secondary questions evaluated program design features that could affect engagement (eg, session frequency). RESULTS: Structured equation modeling found that subjective norms were the strongest significant predictor of intention to participate in exercise for postconcussion recovery. Perceived behavioral control was also a significant predictor of intention to participate but to a lesser extent. Attitude did not predict participation intention. The design features identified as key were personalization and being supervised during the program. CONCLUSIONS: This study found that people's intention to participate in a program of exercise postconcussion recovery is shaped by individual psychological factors and identified program design features that could be adjusted for increased engagement. Program success could be maximized through strategies such as supporting individuals to have a stronger sense of control over their participation through the choice of session timing or frequency and harnessing the influence of significant others via supportive messaging from key professionals.

Exercise Parameters for Postconcussion Symptom Rehabilitation: A Systematic Review.

CONTEXT: Exercise rehabilitation for postconcussion symptoms (PCS) has shown some benefits in adolescent athletes; but a synthesis of evidence on exercise per se has been lacking. OBJECTIVE: This systematic review aimed to determine if unimodal exercise interventions are useful to treat PCS and if so, to identify a set of clearly defined and effective exercise parameters for further research. EVIDENCE ACQUISITION: Relevant health databases and clinical trial registries were searched from inception to June 2022. The searches used a combination of subject headings and keywords related to mild traumatic brain injury (mTBI), PCSs, and exercise. Two independent reviewers screened and appraised the literature. The Cochrane Collaboration's Risk of Bias-2 tool for randomized controlled trials was used to assess methodological quality of studies. EVIDENCE SYNTHESIS: Seven studies were included in the review. Four studies were assessed to have a low overall risk of bias, 2 with low risk and 1 with some concerns. Participants in the studies comprised mostly adolescents with sports-related concussion. The review found exercise to be more beneficial than control conditions in 2 studies investigating acute PCS and 2 studies investigating persistent PCS. Within-group differences showing symptom improvement over time were observed in all 7 studies. In general, the review found support for programmatic exercise that commences after an initial period of rest for 24 to 48 hours. Recommendations for exercise parameters that can be explored in subsequent research include progressive aerobic exercise starting from 10 to 15 minutes at least 4 times a week, at a starting intensity of 50% HR of the subsymptom threshold, with length of program depending on recovery. CONCLUSION: The evidence in support of exercise rehabilitation for PCSs is moderate based on the small pool of eligible studies. Further research can be guided by the exercise parameters identified in this review.

Lower knee flexion and hip extension rate of torque development in athletes with previous hamstring strain injury.

Persistent deficits in strength and voluntary activation have been observed in athletes with a history of hamstring strain injury. The mechanisms contributing to these deficits are poorly understood and consequently may not be appropriately addressed during rehabilitation. This study aimed to investigate the impact of intended knee flexor contraction mode (concentric, eccentric or isometric) on the rate of torque development and surface electromyography (sEMG) rise in athletes with and without a history of unilateral hamstring strain injury. The impact of the previous injury on hip extensor rate of torque development was also investigated. Previously injured limbs exhibited a slower rate of torque development (mean difference = -31%, p = 0.02, Cohen's d = 0.62) and biceps femoris rate of sEMG rise (mean difference = -181% · s-1, p = 0.003, Cohen's d = 1.10) during intended eccentric knee flexor contractions compared with control limbs. Previously injured (mean difference = -29%, p = 0.01, Cohen's d = 0.85) and contralateral uninjured limbs (mean difference = -31%, p = 0.007, Cohen's d = 0.73) exhibited a slower rate of torque development during isometric hip extensor contractions compared with control limbs. These findings may highlight lower levels of descending input to hamstring motoneurons in previously injured athletes.

The hidden hand is perceived closer to midline.

Whether visible or not, knowing the location of our hands is fundamental to how we perceive ourselves and interact with our environment. The present study investigated perceived hand location in the absence of vision in 30 participants. Their right index finger was placed 10, 20 or 30 cm away on either side of the body midline, with and without their left index finger placed 10 cm to the left of the right index. On average, at each position, participants perceived their right hand closer to the body midline than it actually was. This underestimation increased linearly with increased distance of the hand from body midline [slope 0.77 (0.74 to 0.81), mean (95% CI)]. Participants made smaller errors in perceived hand location when the right hand was in the contralateral workspace [mean difference 2.13 cm (1.57 to 2.69)]. Presence of the left hand on the support surface had little or no effect on perceived location of the right hand [mean difference [Formula: see text] cm ([Formula: see text] to 0.02)]. Overall, participants made systematic perceptual errors immediately after hand placement. The magnitude of these errors grew linearly as the hand got further away from the body midline. Because of their magnitude, these errors may contribute to errors in motor planning when visual feedback is not available. Also, these errors are important for studies in which perceived hand location is assessed after some time, for example, when studying illusions of body ownership and proprioceptive drift.

Cardiovascular autonomic responses in patients with Parkinson disease to pedunculopontine deep brain stimulation.

PURPOSE: Dysautonomia can be a debilitating feature of Parkinson disease (PD). Pedunculopontine nucleus (PPN) stimulation may improve gait disorders in PD, and may also result in changes in autonomic performance. METHODS: To determine whether pedunculopontine nucleus stimulation improves cardiovascular responses to autonomic challenges of postural tilt and Valsalva manoeuver, eight patients with pedunculopontine nucleus deep brain stimulation were recruited to the study; two were excluded for technical reasons during testing. Participants underwent head up tilt and Valsalva manoeuver with stimulation turned ON and OFF. Continuous blood pressure and ECG waveforms were recorded during these tests. In a single patient, local field potential activity was recorded from the implanted electrode during tilt. RESULTS: The fall in systolic blood pressure after tilt was significantly smaller with stimulation ON (mean - 8.3% versus - 17.2%, p = 0.044). Valsalva ratio increased with stimulation from median 1.15 OFF to 1.20 ON (p = 0.028). Baroreflex sensitivity increased during Valsalva compared to rest with stimulation ON versus OFF (p = 0.028). The increase in baroreflex sensitivity correlated significantly with the mean depth of PPN stimulating electrode contacts. This accounted for 89% of its variance (r = 0.943, p = 0.005). CONCLUSION: PPN stimulation can modulate the cardiovascular system in patients with PD. In this study, it reduced the postural fall in systolic blood pressure during head-up tilt and improved the cardiovascular response during Valsalva, presumably by altering the neural control of baroreflex activation.

Assessment of abduction motion in patients with rotator cuff tears: an analysis based on inertial sensors.

BACKGROUND: Reduced range of motion in the shoulder can be a source of functional limitation. The use of inertial sensors to quantify movement in addition to more common clinical assessments of the shoulder may allow clinicians to understand that they are potentially unnoticed by visual identification. The aim of this study was to generate an explanatory model for shoulder abduction based on data from inertial sensors. METHOD: A cross-sectional study was carried out to generate an explanatory model of shoulder abduction based on data from inertial sensors. Shoulder abduction of thirteen older adults suffering from shoulder dysfunction was recorded with two inertial sensors placed on the humerus and scapula. Movement variables (maximum angular mobility, angular peak of velocity, peak of acceleration) were used to explain the functionality of the upper limb assessed using the Upper Limb Functional Index (ULFI). The abduction movement of the shoulder was explained by six variables related to the mobility of the shoulder joint complex. A multivariate analysis of variance (MANOVA) was used to explain the results obtained on the functionality of the upper limb. RESULTS: The MANOVA model based on angular mobility explained 69% of the variance of the ULFI value (r-squared = 0.69). The most relevant variables were the abduction-adduction of the humerus and the medial/lateral rotation of the scapula. CONCLUSIONS: The method used in the present study reveals the potential importance of the analysis of the scapular and humeral movements for comprehensive evaluation of the upper limb. Further research should include a wider sample and may seek to use this assessment technique in a range of potential clinical applications.

Dynamics of corticospinal motor control during overground and treadmill walking in humans.

Increasing evidence suggests cortical involvement in the control of human gait. However, the nature of corticospinal interactions remains poorly understood. We performed time-frequency analysis of electrophysiological activity acquired during treadmill and overground walking in 22 healthy, young adults. Participants walked at their preferred speed (4.2, SD 0.4 km/h), which was matched across both gait conditions. Event-related power, corticomuscular coherence (CMC), and intertrial coherence (ITC) were assessed for EEG from bilateral sensorimotor cortices and EMG from the bilateral tibialis anterior (TA) muscles. Cortical power, CMC, and ITC at theta, alpha, beta, and gamma frequencies (4-45 Hz) increased during the double support phase of the gait cycle for both overground and treadmill walking. High beta (21-30 Hz) CMC and ITC of EMG was significantly increased during overground compared with treadmill walking, as well as EEG power in theta band (4-7 Hz). The phase spectra revealed positive time lags at alpha, beta, and gamma frequencies, indicating that the EEG response preceded the EMG response. The parallel increases in power, CMC, and ITC during double support suggest evoked responses at spinal and cortical populations rather than a modulation of ongoing corticospinal oscillatory interactions. The evoked responses are not consistent with the idea of synchronization of ongoing corticospinal oscillations but instead suggest coordinated cortical and spinal inputs during the double support phase. Frequency-band dependent differences in power, CMC, and ITC between overground and treadmill walking suggest differing neural control for the two gait modalities, emphasizing the task-dependent nature of neural processes during human walking. NEW & NOTEWORTHY We investigated cortical and spinal activity during overground and treadmill walking in healthy adults. Parallel increases in power, corticomuscular coherence, and intertrial coherence during double support suggest evoked responses at spinal and cortical populations rather than a modulation of ongoing corticospinal oscillatory interactions. These findings identify neurophysiological mechanisms that are important for understanding cortical control of human gait in health and disease.