The Gegenhalten or paratonia Narrative and conceptual review

Better known in neurology by the expression paratonia coined by Ernest Duprein 1907, the term Gegenhalten has remained dominant in psychiatry. While the term was created by Karl Kleist in 1927 to define a form of hypertonia in order to distinguish it from negativism, many current references continue to conflate the two concepts. Gegenhalten is the most frequent kind of hypertonia, and if its differential diagnosis with spasticity is generally easy, it is more difficult to distinguish it from parkinsonian rigidity, especially in psychiatric settings where antipsychotic-induced (or revealed) parkinsonism is frequent. Problematically, the most used evaluation scale for it, i.e., the Simpson-Angus scale does not allow for the distinction of Gegenhalten from parkinsonism. This could explain some of what is currently referred to as "spontaneous parkinsonism", i.e., a hypertonia reported to occur in psychotic patients who are not taking any antipsychotic medication. Classical Gegenhalten is reactive, i.e., it occurs in the absence of an increase in resting tonus. It opposes an involuntary resistance during passive mobilization, the appearance of which is often delayed, or may only be perceptible after frequent repetitions. Thus, in the absence of a sensitization maneuver, minor forms of Gegenhalten may go undetected. Gegenhalten opposes a variable resistance. For instance, it depends on position (enhanced by gravitation) or emotional arousal. It can also be masked by a Mitmachen, a form of automatic assistance which is also of locomotor origin (like the Gegenhalten). While the French school of psychiatry saw Gegenhalten as a lack of voluntary control of muscle relaxation, Karl Kleist viewed it as an exacerbation of postural fixation reactions. For him, Gegenhalten could also occur "spontaneously" under the simple effect of gravity. Kleist hypothesized that spontaneous Gegenhalten was a kind of hypersensitive postural fixation reaction that could account for catatonic rigidity. These hypotheses were hotly debated at the beginning of the 20th century and stimulated considerable research. The growing interest in motor abnormalities in endogenous psychoses invites us to reconsider them. Unfortunately, they cannot be understood without a return to a refined semiology which has since been forgotten. This review is a first step in this direction. (C) 2022 Published by Elsevier Masson SAS.