Related Experiment Video
Updated: Jul 9, 2026
05:52
Handwriting Analysis Indicates Spontaneous Dyskinesias in Neuroleptic Naïve Adolescents at High Risk for Psychosis
Published on: November 21, 2013
Square wave jerks in children and adolescents
Michael S Salman1, James A Sharpe, Linda Lillakas
1Section of Pediatric Neurology, Children's Hospital, University of Manitoba, Winnipeg, Manitoba, Canada. msalman@hsc.mb.ca
Pediatric Neurology
|December 7, 2007
Summary
Square wave jerks, involuntary saccadic intrusions, are highly prevalent in children and adolescents, occurring in 90% of participants. This high frequency may indicate a less mature brain
Area of Science:
- Ophthalmology
- Neuroscience
- Developmental Neuroscience
Background:
- Square wave jerks are involuntary saccadic intrusions interrupting visual fixation.
- While common in adults, their prevalence in children and adolescents is unknown.
Purpose of the Study:
- To investigate the prevalence and characteristics of square wave jerks in children and adolescents.
- To determine if square wave jerk parameters correlate with age in this demographic.
Main Methods:
- Eye movements were recorded using infrared eye tracking in 38 participants aged 8-19 years during fixation.
- Frequency, duration, amplitude, and peak velocity of square wave jerks were analyzed.
- Data were correlated with participant age.
Main Results:
- Ninety percent of participants exhibited square wave jerks, significantly higher than in adults.
- Median frequency was 3 per minute, median duration 249 ms, median amplitude 0.81 degrees, and median peak velocity 60 degrees/second.
- No square wave jerk parameter correlated with age.
Conclusions:
- Square wave jerks are highly prevalent in children and adolescents, suggesting a potential developmental aspect.
- This high prevalence may reflect immature brain function, specifically reduced suppression of saccadic triggers.
Related Concept Videos
01:27Signs of Puberty
Puberty is a critical phase, typically beginning between the ages of 8 and 13 in girls and 9 and 14 in boys, though timing can vary based on genetics, environmental factors, and overall health. This period is characterized by the development of secondary sexual characteristics and the attainment of reproductive potential. Endocrine changes underpin puberty, with hormonal surges of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) instigated by Gonadotropin-Releasing Hormone (GnRH)...
01:22Muscle Stimulation Frequency
The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
01:06Forced Oscillations
When an oscillator is forced with a periodic driving force, the motion may seem chaotic. The motions of such oscillators are known as transients. After the transients die out, the oscillator reaches a steady state, where the motion is periodic, and the displacement is determined.
01:17Standing Waves
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...
01:06Physical Pendulum
When a rigid body is hanging freely from a fixed pivot point and is displaced, it oscillates similar to a simple pendulum and is known as a physical pendulum. The period and angular frequency of a physical pendulum are obtained by using the small-angle approximation and drawing parallels with a spring-mass system. The small-angle approximation (sinθ=θ) is valid up to about 14°.
When dealing with complicated systems, the mass moment of inertia is an important parameter, as it describes the mass...
When dealing with complicated systems, the mass moment of inertia is an important parameter, as it describes the mass...
01:21Simple Harmonic Motion
Simple harmonic motion is the name given to oscillatory motion for a system where the net force can be described by Hooke's law. If the net force can be described by Hooke's law and there is no damping (by friction or other non-conservative forces), then a simple harmonic oscillator will oscillate with equal displacement on either side of the equilibrium position. To derive an equation for period and frequency, the equation of motion is used. The period of a simple harmonic oscillator is given...