Related Experiment Video
Updated: Jan 28, 2026
08:23
Standing Neurophysiological Assessment of Lower Extremity Muscles Post-Stroke
Published on: July 26, 2021
2.9K
Influence of target uncertainty on reaching movements while standing in stroke
Camila Astolphi Lima1, Sandra Regina Alouche1, Alessandra Maria Schiavinato Baldan2
1Graduate Program in Physical Therapy, Universidade Cidade de São Paulo, Brazil.
Human Movement Science
|March 3, 2019
Summary
Stroke survivors experience balance and arm movement deficits. Target uncertainty impacts arm reaching and postural control, with effects varying based on the stroke
Area of Science:
- Neuroscience
- Biomechanics
- Rehabilitation Science
Background:
- Stroke often leads to impaired arm movements and balance issues, affecting daily activities.
- Understanding how stroke survivors adapt reaching movements and maintain posture is crucial for rehabilitation.
Purpose of the Study:
- To investigate the effects of target uncertainty and lesion side on arm reaching and postural adjustments in stroke individuals.
- To compare motor control strategies between stroke survivors and healthy individuals.
Main Methods:
- Participants performed reaching tasks in a standing position with varying target location certainty.
- Kinematic analysis of arm and lower limb joints and center of pressure (COP) displacements were recorded.
- Stroke individuals used their ipsilesional limb; healthy individuals used both limbs.
Main Results:
- Stroke individuals exhibited greater COP displacements in the contralesional limb compared to the ipsilesional limb.
- Target uncertainty influenced arm movement characteristics and pre-movement postural adjustments.
- Right stroke individuals increased ankle joint activity under uncertain conditions.
Conclusions:
- Target uncertainty affects reaching and postural control in stroke survivors, with distinct patterns based on the brain lesion side.
- Postural adjustments during reaching are asymmetric in stroke survivors, unlike in healthy individuals.
- Findings highlight the importance of considering lesion side and target predictability in stroke rehabilitation for upper limb function and balance.
Related Concept Videos
04:08The Uncertainty Principle
31.8K
Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that there is a fundamental limit to how accurately one can measure both a particle’s position and its momentum simultaneously. The more accurate the measurement of the momentum of a particle is known, the less accurate the position at that time is known and vice versa. This is what is now called the Heisenberg uncertainty principle. He...
31.8K
02:46Uncertainty in Measurement: Reading Instruments
51.5K
Counting is the type of measurement that is free from uncertainty, provided the number of objects being counted does not change during the process. Such measurements result in exact numbers. By counting the eggs in a carton, for instance, one can determine exactly how many eggs are there in the carton. Similarly, the numbers of defined quantities are also exact. For example, 1 foot is exactly 12 inches, 1 inch is exactly 2.54 centimeters, and 1 gram is exactly 0.001 kilograms. Quantities...
51.5K
00:59Uncertainty: Overview
1.7K
In analytical chemistry, we often perform repetitive measurements to detect and minimize inaccuracies caused by both determinate and indeterminate errors. Despite the cares we take, the presence of random errors means that repeated measurements almost never have exactly the same magnitude. The collective difference between these measurements - observed values - and the estimated or expected value is called uncertainty. Uncertainty is conventionally written after the estimated or expected value.
1.7K
03:37Uncertainty in Measurement: Accuracy and Precision
100.9K
Scientists typically make repeated measurements of a quantity to ensure the quality of their findings and to evaluate both the precision and the accuracy of their results. Measurements are said to be precise if they yield very similar results when repeated in the same manner. A measurement is considered accurate if it yields a result that is very close to the true or the accepted value. Precise values agree with each other; accurate values agree with a true value.
100.9K
01:17Standing Waves
5.4K
Sometimes waves do not seem to move; rather, they just vibrate in place. Unmoving waves can be seen on the surface of a glass of milk kept in a refrigerator, which is one example of standing waves. Vibrations from the refrigerator motor create waves on the milk that oscillate up and down but do not seem to move across the surface. These waves are formed or created by the superposition of two or more identical moving waves in opposite directions. The waves move through each other, with their...
5.4K
03:34Uncertainty in Measurement: Significant Figures
81.5K
All the digits in a measurement, including the uncertain last digit, are called significant figures or significant digits. Note that zero may be a measured value; for example, if a scale that shows weight to the nearest pound reads “140,” then the 1 (hundreds), 4 (tens), and 0 (ones) are all significant (measured) values.
81.5K