Stereotypies: A critical appraisal and suggestion of a clinically useful definition

Abstract

The foundations of the clinical classification of movement disorders rest on the precise definition of the words used to describe the disorders. Here we argue that the current use of the term stereotypy falls well short of the precision needed for either clinical or academic use, and fails both to provide a clinically useful diagnostic category and to define a set of conditions that are linked pathophysiologically. The difficulty in defining this concept is not a new one as our review of the history of the term demonstrates. We synthesise this historical background, explore why clinicians have felt it necessary to use the category of stereotypy for certain movements rather than the related category of tics, discuss the multiple uses of the term in current research and clinical practice and on this basis suggest a new definition and classification.

Intermittent head drops: the differential spectrum

“…Phenomenological similarities bridge tics to stereotypies,19 although the lack of urgency to perform the movements, and their suppression by distraction, can allow distinction between stereotypies and tics 20. Head stereotypies are quite common.…”

“…Additionally, IHDs’ duration can also be helpful. The briefest occur in myoclonic seizures and epileptic spasms (millis),7 15 16 the intermediate in cataplectic episodes,3 4 37 39 stereotypies,19 20 tics18 and chorea (seconds to minutes),1 2 25 26 and the longest are seen in paroxysmal dyskinesia,30–32 or Sandifer syndrome (minutes to hours) 43 44. The particular phenomenology of IHDs can also aid in the differential diagnosis.…”

Characterising repetitive behaviours in young boys with fragile X syndrome

“…Repetitive behaviours refer to a broad heterogeneous category of behaviours characterised by the repetition of unvarying movements (Edwards et al 2012), rigidity, and inappropriateness (Lewis & Kim 2009). Typically developing infants and young children commonly engage in repetitive behaviours and activities.…”

Leg stereotypy syndrome: phenomenology and prevalence

“…Stereotypy has been defined as ‘a non – goal-directed movement pattern that is repeated continuously for a period of time in the same form and on multiple occasions, which is typically distractible’ 3. Other definitions of stereotypy emphasise coordinated, patterned, repetitive, rhythmic, seemingly purposeless movements that can occur involuntarily or in response to or induced by inner sensory stimulus or unwanted feeling (involuntary) 4–6.…”