Tremor: Is Parkinson’s disease a dynamical disease?

Abstract

Experimental evidence has shown a plethora of short-term fluctuations in patients with Parkinson's disease. We investigate these transitory events using the concept of dynamical disease. Several examples of short-term fluctuations in tremor are analyzed, and in two cases, other systemic variables (i.e., respiration and blood pressure) are examined as well. A model for tremor, based on negative feedback with delays is proposed, and the transient events are simulated. The theoretical implications of the model suggest that interactions between the central and peripheral loops, as well as interactions between the control loops and other systemic signals, can give rise to transitory events in tremor, both in the pathological and in the normal case. (c) 1995 American Institute of Physics.

Parkinsonian Tremor and Simplification in Network Dynamics

“…Thus, it seems plausible that PD is a 'dynamical disease' in the sense that it arises from normal tremor via bifurcations in a dynamical process. This was previously suggested by Beuter and Vasilakos (1995b), where the reversibility of symptoms in PD by pharmacological and electrical interventions were also argued to support the idea, though the model presented there was different.…”

“…The higher amplitude regular oscillations can appear and disappear suddenly or gradually (Gurfinkel and Osovets, 1973;Beuter and Vasilakos, 1995a;Edwards and Beuter, 1996). This suggests that the parameters determining the dynamical regime are also fluctuating, or that additional inputs are being given to the network from other areas (voluntary commands or anxiety, for example, can alter tremor), or that other systemic variables such as the ballistocardiogram are modifying the dynamics via peripheral feedback (Beuter and Vasilakos, 1995b).…”

Modelling Perspectives on Aging: Can Mathematics Help us Stay Young?

“…Beuter & Vasilakos (1995) investigated the possibility that the oscillations in muscle control that show up as tremor in Parkinson's disease can be considered as a MODELLING PERSPECTIVES ON AGING dynamical disorder: abnormal oscillations appear (tremor), normal rhythms disappear (e.g. reduced swinging of arms in walking) and new periodicities develop; all these features are suggestive of the hypothesis of a dynamic disorder.…”

“…reduced swinging of arms in walking) and new periodicities develop; all these features are suggestive of the hypothesis of a dynamic disorder. The idea proposed by Beuter & Vasilakos (1995) is that central and peripheral feedback loops interact dynamically to control limb position, the former having greater impact, and the latter responsible for minor corrections. Changes in the coupling between these systems over time could lead to the changes in dynamics.…”

Dynamics of the Subthalamo-pallidal Complex in Parkinson’s Disease During Deep Brain Stimulation

“…The reversibility of PD symptoms [12] led Beuter and Vasilakos [13] to qualify PD as a dynamical disease. Mackey and Glass [14] defined a dynamical disease as abnormal dynamics appearing when a control parameter, e.g., the concentration of a hormone or neurotransmitter, is out of range.…”