Characterizing freezing of gait in Parkinson's disease: Models of an episodic phenomenon

Abstract

Freezing of gait (FOG) is a very disabling and common gait disorder in Parkinson"s disease (PD). The first aim of this paper is to provide a methodological and critical review of the most common research approach to understand FOG, i.e., comparing the behaviour of freezers with that of non-freezers. The review shows that studies often fall short in clearly defining the freezer\non-freezer groups and in controlling for disease severity and other confounders.These problems complicate data interpretation on FOG.The second aim of this paper was to summarize the literature on the potential mechanisms behind the episodic nature of FOG in the following four models: 1) The "threshold model" assumes that FOG occurs when the accumulation of various motor deficits reinforce each other to a point of motor breakdown; 2) The "interference model" proposes that FOG represents an inability to deal with concurrent cognitive, limbic and motor input, causing an interruption of locomotion; 3) The "cognitive model" views FOG as induced by a failure to process response conflict, leading to behavioural indecision; and 4) the "decoupling model" sees FOG as a disconnection between preparatory programming and the intended motor response as a result of which automatic movement generation gets stuck. These four theoretical premises are still incomplete and do not fully explain FOG. The depletion of motor and cognitive reserves and an increasingly complex response to levodopa with disease progression will also impact upon the emergence of the FOG-episodes.3

Specific Attentional Disorders and Freezing of Gait in Parkinson’s Disease

“…It has a major impact on quality of life [2,3] and increases the risk of falls [4]. Several studies have sought to identify the determinants of FoG in Parkinson's disease (PD) [1,5] with motor and cognitive or interplaying (overload) hypotheses [6,7]. Amboni et al's "cognitive hypothesis" [8] on one hand and poor ability to resist interference (i.e.…”

Neuromuscular correlates of subthalamic stimulation and upper limb freezing in Parkinson’s disease

“…Here, we discuss our findings in the context of previous models on freezing of gait (Nieuwboer and Giladi, 2013): Our paradigm was designed according to the interference hypotheses (inducing a cortical processing conflict by a second cognitive task). Nevertheless, ULF in our study was rather complemented by further mechanisms.…”

Deep Learning for Detecting Freezing of Gait Episodes in Parkinson’s Disease Based on Accelerometers

“…Suffering FOG episodes may provoke falling accidents when patients are willing to perform walking related actions [3]. According to Nieuwboer and Giladi [14], FOG might be defined as an inability to deal with concurrent cognitive, limbic, and motor inputs, causing an interruption of locomotion. Many medical research studies have been carried out to discover strategies to combat this symptom.…”