Disorders of Reactive Movements
Reactive movements are the immediate, automatic adjustments a person makes to new stimuli, such as flinching at a sudden threat or turning toward an unexpected sound. They give an overall impression of alertness and engagement with the surrounding world. A disturbance can go in either direction: reactive movements may be diminished or lost, giving a stiff, unresponsive impression, or they may become excessive and overly prompt.
This has traditionally been considered alongside obstruction, since the two frequently occur together in catatonia and stupor, where a general loss of reactive movement compounds an already stiff, disjointed pattern of voluntary movement.
Recognition features
- Diminished or absent automatic response to new stimuli, such as a lack of flinching to a sudden movement or lack of turning toward a sudden sound
- Gives an overall impression of stiffness and unresponsiveness to the surrounding environment that can be hard to describe precisely
- In severe anxiety, reactive movements may instead be prompt and excessive, well beyond what the stimulus would warrant
- Frequently co-occurs with obstruction in catatonia and stupor, compounding the overall stiff, disjointed quality of movement
Eliciting it at interview
- Observe the person's automatic response to ordinary environmental changes during the interview, such as a knock at the door or a dropped object, and note whether the response seems diminished, absent, or excessive
- Distinguish a generally diminished responsiveness from a specific, deliberate lack of reaction to one particular stimulus, which may instead suggest negativism
- Consider and screen for a neurological contribution, such as parkinsonism, which is also recognised to reduce reactive movements
Distinguishing features
- Differs from negativism, in which the lack of response to a specific stimulus is an apparently motiveless active resistance, rather than a general reduction in automatic responsiveness across the board
- Differs from obstruction, which specifically concerns an irregular hindrance to voluntary, goal-directed movement, though the two frequently co-occur in catatonia
- The direction of the disturbance (diminished versus excessive) points toward different underlying conditions: catatonia and parkinsonism for diminished reactivity, severe anxiety for excessive reactivity
Common misconceptions
- That a stiff, unresponsive impression always reflects a deliberate choice not to engage; it is often an involuntary reduction in automatic reactive movement rather than a chosen stance
- That excessive reactive movement is simply nervousness; in severe anxiety it represents a genuine, measurable increase in the promptness and scale of automatic responses
Related phenomena
Obstruction (Blocking) · Negativism
Practice this
A catatonic patient shows a general, stiff unresponsiveness, failing to flinch at a sudden loud noise or turn toward unexpected movement nearby, without any sense that she is deliberately resisting or refusing anything in particular. What is this? · When an examiner asks a patient to open his mouth, the patient instead clamps it firmly shut, and when asked to raise his arm, he lowers it instead, in what appears to be a consistent, reflex-like pattern of doing the opposite of every instruction given. Before revealing the answer: is this a disorder of reactive movements? · A patient shows an unusual pattern of responsiveness to stimuli in their environment. Before revealing the answer, decide what distinguishes a disorder of reactive movements from negativism. · You suspect a disorder of reactive movements in a patient. Before revealing the answer, decide how you would assess for this. · Explain why a disorder of reactive movements is described as able to go in either direction, diminished or excessive.
Illustration
During a ward round, a nurse accidentally drops a metal tray with a loud clatter directly behind a 47-year-old man with catatonia, who shows no startle, flinch, or change in his fixed posture whatsoever, in sharp contrast to every other patient in the room who turns immediately toward the noise.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 8, 'Motor Disorders'.