A stereotypy (, or ) is a repetitive or ritualistic movement, posture, or utterance. Stereotypies may be simple movements such as body rocking, or complex, such as self-caressing, crossing and uncrossing of legs, and marching in place. They are found especially in people with
autism spectrum disorder
The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental disorder, neurodevelopmental condition (or conditions) ...
s and
visually impaired children, and are also found in
intellectual disabilities
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation,Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signific ...
,
tardive dyskinesia
Tardive dyskinesia (TD) is a disorder that results in involuntary repetitive body movements, which may include grimacing, sticking out the tongue or smacking the lips. Additionally, there may be rapid jerking movements or slow writhing movemen ...
and
stereotypic movement disorder
Stereotypic movement disorder (SMD) is a motor disorder with onset in childhood involving restrictive and/or repetitive, nonfunctional motor behavior (e.g., hand waving or head banging), that markedly interferes with normal activities or results i ...
, yet may also be encountered in neurotypical individuals as well. Studies have shown stereotypies associated with some types of
schizophrenia
Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...
.
Frontotemporal dementia
Frontotemporal dementia (FTD), or frontotemporal degeneration disease, or frontotemporal neurocognitive disorder, encompasses several types of dementia involving the progressive degeneration of frontal and temporal lobes. FTDs broadly present as ...
is also a common neurological cause of repetitive behaviors and stereotypies.
Several causes have been hypothesized for stereotypy, and several treatment options are available.
Stereotypy is sometimes called ''
stimming
Self-stimulatory behavior, also known as "stimming" and self-stimulation, is the repetition of physical movements, sounds, words, moving objects, or other repetitive behaviors. Such behaviors (also scientifically known as ' stereotypies') are fo ...
'' in autism, under the hypothesis that it self-stimulates one or more senses.
[
Among people with ]frontotemporal lobar degeneration
Frontotemporal lobar degeneration (FTLD) is a pathological process that occurs in frontotemporal dementia. It is characterized by atrophy in the frontal lobe and temporal lobe of the brain, with sparing of the parietal and occipital lobes.
Common ...
, more than half (60%) had stereotypies. The time to onset of stereotypies in people with frontotemporal lobar degeneration may be years (average 2.1 years).
Distinction from tics
Like tic
A tic is a sudden, repetitive, nonrhythmic motor movement or vocalization involving discrete muscle groups.American Psychiatric Association (2000)DSM-IV-TR: Tourette's Disorder.''Diagnostic and Statistical Manual of Mental Disorders'', 4th ed., ...
s, stereotypies are patterned and periodic, and are aggravated by fatigue, stress, and anxiety. Unlike tics, stereotypies usually begin before the age of three, involve more of the body, are more rhythmic and less random, and are associated more with engrossment in another activity rather than premonitory urges. Examples of early tics are things like blinking and throat clearing, while arm flapping is a more common stereotypy. Stereotypies do not have the ever-changing, waxing and waning nature of tics, and can remain constant for years. Tics are usually suppressible for brief periods; in contrast, children rarely consciously attempt to control a stereotypy, although they can be distracted from one.
Proposed causes
There are several possible explanations for stereotypy, and different stereotyped behaviors may have different explanations. A popular explanation is stimming
Self-stimulatory behavior, also known as "stimming" and self-stimulation, is the repetition of physical movements, sounds, words, moving objects, or other repetitive behaviors. Such behaviors (also scientifically known as ' stereotypies') are fo ...
, which hypothesizes that a particular stereotyped behavior has a function related to sensory input. Other explanations include hypotheses that stereotypy discharges tension or expresses frustration, that it communicates a need for attention or reinforcement or sensory stimulation, that it is learned or neuropathological or some combination of the two, or that it is normal behavior with no particular explanation needed.
Associated terms
Punding
Punding is compulsive performance of repetitive, mechanical tasks, such as assembling and disassembling, collecting, or sorting household objects. The term was originally coined to describe complex prolonged, purposeless, and stereotyped behaviou ...
is a term that was coined originally to describe complex prolonged, purposeless, and stereotyped behavior in chronic amphetamine
Amphetamine (contracted from alpha- methylphenethylamine) is a strong central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity. It is also commonly used ...
users; it was later described in Parkinson's disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
. Punding is a compulsion to perform repetitive mechanical tasks, such as sorting, collecting, or assembling and disassembling common items. Punding may occur in individuals with Parkinson's disease treated with dopaminergic agents such as L-DOPA
-DOPA, also known as levodopa and -3,4-dihydroxyphenylalanine, is an amino acid that is made and used as part of the normal biology of some plants and animals, including humans. Humans, as well as a portion of the other animals that utilize -DOPA ...
.
Tweaking is a slang term for compulsive or repetitive behavior; it refers to someone exhibiting pronounced symptoms of methamphetamine
Methamphetamine (contracted from ) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Methamph ...
or amphetamine use.
In animals
Stereotypies also occur in non-human animals. It is considered an abnormal behavior
Abnormality (or dysfunctional behavior) is a behavioral characteristic assigned to those with conditions that are regarded as rare or dysfunctional. Behavior is considered to be abnormal when it is atypical or out of the ordinary, consists of u ...
and is sometimes seen in captive animals, particularly those held in small enclosures with little opportunity to engage in more normal behaviors. These behaviors may be maladaptive, involving self-injury or reduced reproductive success, and in laboratory animals can confound behavioral research. Examples of stereotyped behaviors include pacing, rocking, swimming in circles, excessive sleeping, self-mutilation (including feather picking and excessive grooming), and mouthing cage bars. Stereotypies are seen in many species, including primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...
s, birds, and carnivore
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
s. Up to 40% of elephants in zoos display stereotyped behaviors. Stereotypies are well known in stable
A stable is a building in which livestock, especially horses, are kept. It most commonly means a building that is divided into separate stalls for individual animals and livestock. There are many different types of stables in use today; the ...
d horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million y ...
s, usually developing as a result of being confined, particularly with insufficient exercise. They are colloquially called stable vices
Stable vices are stereotypies of equines, especially horses. They are usually undesirable habits that often develop as a result of being confined in a stable with boredom, hunger, isolation, excess energy, or insufficient exercise. They present ...
. They present a management
Management (or managing) is the administration of an organization, whether it is a business, a nonprofit organization, or a government body. It is the art and science of managing resources of the business.
Management includes the activities o ...
issue, not only leading to facility damage from chewing, kicking, and repetitive motion, but also lead to health consequences for the animal if not addressed.
Stereotyped behaviors are thought to be caused ultimately by artificial environments that do not allow animals to satisfy their normal behavioral needs. Rather than refer to the behavior as abnormal, it has been suggested that it be described as "behavior indicative of an abnormal environment." Stereotypies are correlated with altered behavioral response selection in the basal ganglia
The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...
. As stereotypies are frequently viewed as a sign of psychological distress in animals, there is also an animal welfare
Animal welfare is the well-being of non-human animals. Formal standards of animal welfare vary between contexts, but are debated mostly by animal welfare groups, legislators, and academics. Animal welfare science uses measures such as longevity ...
issue involved.
Stereotyped behavior can sometimes be reduced or eliminated by environmental enrichment
Environmental enrichment is the stimulation of the brain by its physical and social surroundings. Brains in richer, more stimulating environments have higher rates of synaptogenesis and more complex dendrite arbors, leading to increased brain ac ...
, including larger and more stimulating enclosures, training, and introductions of stimuli (such as objects, sounds, or scents) to the animal's environment. The enrichment must be varied to remain effective for any length of time. Housing social animals with other members of their species is also helpful. But once the behavior is established, it is sometimes impossible to eliminate due to alterations in the brain.
References
External links
* Chinthapalli V. M.; Singer H. S
Stereotypies of infancy and childhood.
April 19, 2010. Retrieved on November 30, 2010.
Photo & video library of stereotypic behavior in captive animals
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Ethology
Animal welfare
Addiction
Symptoms and signs of mental disorders
Abnormal behaviour in animals