An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.

Mild intellectual disability is defined as an intelligence quotient (IQ) in the range of 50-69.

An acute dystonic reaction with blepharospasm, periorbital twitches, and protracted fixed staring episodes. There may be a maximal upward deviation of the eyes in the sustained fashion. Oculogyric crisis can be triggered by a number of factors including neuroleptic medications.

Bradykinesia literally means slow movement, and is used clinically to denote a slowness in the execution of movement (in contrast to hypokinesia, which is used to refer to slowness in the initiation of movement).

Characteristic neurologic anomaly resulting from degeneration of dopamine-generating cells in the substantia nigra, a region of the midbrain, characterized clinically by shaking, rigidity, slowness of movement and difficulty with walking and gait.

A degree of language development that is significantly below the norm for a child of a specified age.

A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.

An abnormal gait pattern in which persons stand and walk with their feet spaced widely apart. This is often a component of cerebellar ataxia.

Attention-deficit/hyperactivity disorder (ADHD) is a behavioral disorder that typically begins in childhood and is characterized by a short attention span (inattention), an inability to be calm and stay still (hyperactivity), and poor impulse control (impulsivity). Some people with ADHD have problems with only inattention or with hyperactivity and impulsivity, but most have problems related to all three features.\n\nIn people with ADHD, the characteristic behaviors are frequent and severe enough to interfere with the activities of daily living such as school, work, and relationships with others. Because of an inability to stay focused on tasks, people with inattention may be easily distracted, forgetful, avoid tasks that require sustained attention, have difficulty organizing tasks, or frequently lose items.\n\nIn most affected individuals, ADHD continues throughout life, but in about one-third of individuals, signs and symptoms of ADHD go away by adulthood.\n\nHyperactivity is usually shown by frequent movement. Individuals with this feature often fidget or tap their foot when seated, leave their seat when it is inappropriate to do so (such as in the classroom), or talk a lot and interrupt others.\n\nImpulsivity can result in hasty actions without thought for the consequences. Individuals with poor impulse control may have difficulty waiting for their turn, deferring to others, or considering their actions before acting.\n\nMore than two-thirds of all individuals with ADHD have additional conditions, including insomnia, mood or anxiety disorders, learning disorders, or substance use disorders. Affected individuals may also have autism spectrum disorder, which is characterized by impaired communication and social interaction, or Tourette syndrome, which is a disorder characterized by repetitive and involuntary movements or noises called tics.

A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move.

Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.

Generalized muscular hypotonia (abnormally low muscle tone).

Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.