| 1. |
- Patel, Mitesh, et al.
(author)
-
Effects of Deep Brain Stimulation on Postural Control in Parkinson's Disease
- 2020
-
In: Computers in Biology and Medicine. - : Elsevier BV. - 0010-4825. ; 122
-
Journal article (peer-reviewed)abstract
- The standard approach to the evaluation of tremor in medical practice is subjective scoring. The objective of this study was to show that signal processing of physiological data, that are known to be altered by tremor in Parkinson's disease (PD), can quantify the postural dynamics and the effects of DBS. We measured postural control and its capacity to adapt to balance perturbations with a force platform and perturbed balance by altering visual feedback and using pseudo-random binary sequence perturbations (PRBS) of different durations. Our signal processing involved converting the postural control data into spectral power with Fast-Fourier Transformation across a wide bandwidth and then subdividing this into three bands (0–4 Hz, 4–7 Hz and 7–25 Hz). We quantified the amount of power in each bandwidth. From 25 eligible participants, 10 PD participants (9 males, mean age 63.8 years) fulfilled the inclusion criteria; idiopathic PD responsive to L-Dopa; >1 year use of bilateral STN stimulation. Seventeen controls (9 males, mean age 71.2 years) were studied for comparison. Participants with PD were assessed after overnight withdrawal of anti-PD medications. Postural control was measured with a force platform during quiet stance (35 s) and during PRBS calf muscle vibration that perturbed stance (200 s). Tests were performed with eyes open and eyes closed and with DBS ON and DBS OFF. The balance perturbation period was divided into five sequential 35-s periods to assess the subject's ability to address postural imbalance using adaptation. The signal processing analyses revealed that DBS did not significantly change the dynamics of postural control in the 0–4 Hz spectral power but the device reduced the use of spectral power >4 Hz; a finding that was present in both anteroposterior and lateral directions, during vibration, and more so in eyes open tests. Visual feedback, which usually improves postural stability, was less effective in participants with PD with DBS OFF across all postural sway frequencies during quiet stance and during balance perturbations. The expected adaptation of postural control was found in healthy participants between the first and last balance perturbation period. However, adaptation was almost abolished across all spectral frequencies in both the anteroposterior and lateral directions, with both eyes open and eyes closed and DBS ON and OFF in participants with PD. To conclude, this study revealed that DBS altered the spectral frequency dynamics of postural control in participants through a reduction of the power used >4 Hz. Moreover, DBS tended to increase the stabilizing effect of vision across all spectral bands. However, the signal processing analyses also revealed that DBS was not able to restore adaptive motor control abilities in PD.
|
|
| 2. |
- Patel, Mitesh, et al.
(author)
-
Effects of 24-h and 36-h Sleep Deprivation on Human Postural Control and Adaptation.
- 2008
-
In: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 185:2, s. 165-173
-
Journal article (peer-reviewed)abstract
- This study investigated whether human postural stability and adaptation were affected by sleep deprivation and the relationship between motor performance and subjective scores of sleepiness (visuo-anlogue sleepiness scores, VAS). Postural stability and subjective sleepiness were examined in 18 healthy subjects (mean age 23.8 years) following 24 and 36 h of continued wakefulness, ensured by portable EEG recordings, and compared to a control test where the assessments were made after a normal night of sleep. The responses were assessed using posturography with eyes open and closed, and vibratory proprioceptive stimulations were used to challenge postural control. Postural control was significantly affected after 24 h of sleep deprivation both in anteroposterior and in lateral directions, but less so after 36 h. Subjective VAS scores showed poor correlation with indicators of postural control performance. The clearest evidence that sleep deprivation decreased postural control was the reduction of adaptation. Also several near falls after 2–3 min during the posturographic tests showed that sleep deprivation might affect stability through momentary lapses of attention. Access to vision, somewhat, but not entirely reduced the effect of sleep deprivation. In conclusion, sleep deprivation can be a contributing factor to decreased postural control and falls.
|
|
| 3. |
- Patel, Mitesh, et al.
(author)
-
Effects of Ageing on Adaptation during Vibratory Stimulation of the Calf and Neck Muscles.
- 2009
-
In: Gerontology. - : S. Karger AG. - 1423-0003 .- 0304-324X. ; 55, s. 82-91
-
Journal article (peer-reviewed)abstract
- Background: The ability to adapt and habituate based on prior experiences is important for human movement control, fall prevention and for the ability to enhance performance during various human activities. However, little is known about the ability for the elderly to adapt to balance perturbations in the lateral direction. Objective: To determine whether adaptation, i.e., the ability to adjust postural control to handle balance perturbations better over time, differed in the elderly subjects compared with young subjects in the anteroposterior and lateral directions, and whether the site of the balance perturbation or the presence or absence of vision affected the response. Methods: Postural stability was measured as anteroposterior and lateral torque variance in a young group (n = 18 (9 female and 9 male), average age = 29.1 years) and an elderly group (n = 16 (5 female and 11 male), average age = 71.5 years) with eyes open and closed during balance perturbations from calf and neck vibrations. After a 30-s period of quiet stance, these vibrations were repeated over a period of 200 s, so the adaptive responses could be analyzed by splitting the data into 50-s periods. Results: The adaptive responses in the anteroposterior and lateral directions were different. Adaptation in the anteroposterior direction occurred to an almost equal extent in the elderly and young, whereas adaptation in the lateral direction was markedly larger in the elderly in all tests except for neck vibration with eyes closed. Age, vision and vibration site were all influential factors for recorded body movements, but no significant combined effects were found. Conclusion: Balance perturbation instigates an adaptive response in the elderly in both the anteroposterior and lateral directions. However, during perturbation, age and vision are both very influential factors for the stability, thus associating the previously documented age-related decline in visual functioning with a higher risk of falls in this age range.
|
|
| 4. |
- Rodell Olgaç, Christina, 1948-
(author)
-
Romskt föreningsarbete bland barn och ungdomar : på väg mot ett organisationskapital
- 2012. - 1
-
In: Den interkulturella blicken i pedagogik. - Huddinge : Södertörns högskola. - 9789186069513 ; , s. 135-154
-
Book chapter (peer-reviewed)abstract
- Utgångspunkten i artikeln tas i det material som insamlades för en uppföljning av 27 romska projekt som under perioden 1996-2009 beviljades medel från Allmänna arvsfonden för olika typer av insatser riktade till romska barn, ungdomar och unga vuxna. Syftet är att identifiera de frågor som av romer själva har betraktats som angelägna att arbeta med och vidare att ur ett interkulturellt perspektiv belysa och analysera vilken utveckling som pågår mer generellt i det romska föreningslivet i Sverige idag.
|
|
| 5. |
|
|
| 6. |
- Brout, Dillon, et al.
(author)
-
The Pantheon+ analysis : supercal-fragilistic cross calibration, retrained SALT2 light-curve model, and calibration systematic uncertainty
- 2022
-
In: Astrophysical Journal. - : Institute of Physics (IOP). - 0004-637X .- 1538-4357. ; 938:2
-
Journal article (peer-reviewed)abstract
- We present a recalibration of the photometric systems in the Pantheon+ sample of Type Ia supernovae (SNe Ia) including those in the SH0ES distance-ladder measurement of H0. We utilize the large and uniform sky coverage of the public Pan-STARRS stellar photometry catalog to cross calibrate against tertiary standards released by individual SN Ia surveys. The most significant updates over the “SuperCal” cross calibration used for the previous Pantheon and SH0ES analyses are: (1) expansion of the number of photometric systems (now 25) and filters (now 105), (2) solving for all filter offsets in all systems simultaneously to produce a calibration uncertainty covariance matrix for cosmological-model constraints, and (3) accounting for the change in the fundamental flux calibration of the Hubble Space Telescope CALSPEC standards from previous versions on the order of 1.5% over a Δλ of 4000 Å. We retrain the SALT2 model and find that our new model coupled with the new calibration of the light curves themselves causes a net distance modulus change (dμ/dz) of 0.04 mag over the redshift range 0 < z < 1. We introduce a new formalism to determine the systematic impact on cosmological inference by propagating the covariance in the fitted calibration offsets through retraining simultaneously with light-curve fitting and find a total calibration uncertainty impact of σw = 0.013; roughly half the size of the sample statistical uncertainty. Similarly, we find the systematic SN calibration contribution to the SH0ES H0 uncertainty is less than 0.2 km s−1 Mpc−1, suggesting that SN Ia calibration cannot resolve the current level of the “Hubble Tension.”
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Thompson, Andrew G B, et al.
(author)
-
Evaluation of plasma tau and neurofilament light chain biomarkers in a 12-year clinical cohort of human prion diseases.
- 2021
-
In: Molecular psychiatry. - : Springer Science and Business Media LLC. - 1476-5578 .- 1359-4184. ; 26, s. 5955-5966
-
Journal article (peer-reviewed)abstract
- Prion diseases are fatal neurodegenerative conditions with highly accurate CSF and imaging diagnostic tests, but major unmet needs for blood biomarkers. Using ultrasensitive immuno-assays, we measured tau and neurofilament light chain (NfL) protein concentrations in 709 plasma samples taken from 377 individuals with prion disease during a 12year prospective clinical study, alongside healthy and neurological control groups. This provides an unprecedented opportunity to evaluate their potential as biomarkers. Plasma tau and NfL were increased across all prion disease types. For distinguishing sCJD from control groups including clinically-relevant "CJD mimics", both show considerable diagnostic value. In sCJD, NfL was substantially elevated in every sample tested, including during early disease with minimal functional impairment and in all follow-up samples. Plasma tau was independently associated with rate of clinical progression in sCJD, while plasma NfL showed independent association with severity of functional impairment. In asymptomatic PRNP mutation carriers, plasma NfL was higher on average in samples taken within 2years of symptom onset than in samples taken earlier. We present biomarker trajectories for nine mutation carriers healthy at enrolment who developed symptoms during follow-up. NfL started to rise as early as 2years before onset in those with mutations typically associated with more slowly progressive clinical disease. This shows potential for plasma NfL as a "proximity marker", but further work is needed to establish predictive value on an individual basis, and how this varies across different PRNP mutations. We conclude that plasma tau and NfL have potential to fill key unmet needs for biomarkers in prion disease: as a secondary outcome for clinical trials (NfL and tau); for predicting onset in at-risk individuals (NfL); and as an accessible test for earlier identification of patients that may have CJD and require more definitive tests (NfL). Further studies should evaluate their performance directly in these specific roles.
|
|
| 10. |
|
|
