Lyon Community Control Programme of Hypertension: Community Analysis

Contribution of Jules Froment to the study of Parkinsonian rigidity

“…These latter cases were frequently encountered during the 1920s because of the epidemic of Von Economo encephalitis. His studies resulted in a large series of important scientific communications primarily presented at the Paris Neurological Society and published thereafter in Revue Neurologique [16][17][18][19][20][21][22][23][24][25][26] and as short communications in American neurological literature. 27,28 both in normal conditions and in neurological diseases.…”

“…More specifically, could parkinsonian rigidity vary with the conditions of the neurological examination (rest, seated, lying on bed)? Indeed, Froment was aware of the cogwheel phenomenon that he called the Negro-Moyer phenomenon, 23 and had noticed that rigidity actually varied from one moment to another within a few minutes or even seconds in the same patient. To answer these fundamental questions, and as explained in a review of his experiments conducted in 1926, 23 Froment used a systematic and stepwise approach to understand the physiological laws underlying parkinsonian rigidity.…”

“…Froment hypothesized that parkinsonian rigidity could vary with changes in body posture. 23 To conduct his experiments, Froment studied muscular tone in different postures so as to induce varying antigravity forces. He first investigated several conditions where antigravity forces could be suppressed or markedly diminished, as floating in a swimming pool, lying in a steam bath (hammam) or in a bathtub at 40°C.…”

“…He first investigated several conditions where antigravity forces could be suppressed or markedly diminished, as floating in a swimming pool, lying in a steam bath (hammam) or in a bathtub at 40°C. 22,23 A more practical posture for laboratory study was the seated position in a comfortable armchair (Morris chair or "fauteuil colonial " in French), where all the parts of the subject's body including the head were completely supported. In this setting, there was no need for antigravity contraction as the limb was supported (the support providing the resistance to gravity).…”

“…For example, bending over to reach for an object, walking on tip toes or standing on one leg induced transient wrist stiffening for a few seconds and then the tone relaxed. 19,20,23 From these observations, Froment and Gardère concluded that there were two types of stabilization mechanisms that protect against postural abberations. First, the maintenance stabilization mechanisms (called "stabilization a minima" in French), that hold the pelvis and the trunk in the normal erect position so as to produce muscular contractions that are active in an unstressed condition.…”