Freezing of Gait
Freezing of Gait
Freezing of gait (FOG) is a gait disturbance, interrupting walking (Ref: 1), with a "sudden and transient” nature (Ref: 2) which may occur in PD patients and which is seriously debilitating. During FOG episodes the subject often perceives complete inability to continue with locomotion. FOG episodes increase the risk for falls (Ref: 3), and have a considerable negative impact on the quality of life (Ref: 4).
Some patients develop 'tricks' to overcome freezing attacks (e.g. marching to a command, stepping over inverted cane , walking to music or a beat, and shifting body weight (Ref: 5)) which all aim to provide sensory-motor drive in order to overcome the freezing. More controlled application of sensory cueing was found effective in improving gait pattern among PD patients in general, in particular those who are based on external rhythmic auditory stimulation (Ref: 6). This approach led to the idea that PD patients who suffer from FOG may benefit from external cues and to the idea that the external cues could be provided in closed loop to the patients, when freezing of gait is detected.
However, most existing technical wearable systems were designed to identify freezing offline (aposteriori analysis). This is not suitable for a rehabilitation system for persons with FOG. In such case, freeze episodes need to be predicted shortly before they are about to occur, and a rehabilitation program must be devised.
CuPiD will realize freezing-of-gait rehabilitation by predicting the onset of a freezing episode, and providing a form of feedback (e.g. rhythmic auditory stimulation) shortly before the freeze. This can be used by a trained subject to consciously balance their body weight according to the rhythm, and thus provide their own assistance. Through repeated practice, users internalize this process, developing an ability to overcome and manage freezing episodes autonomously.
Scenario of use
Mr John has suffered from PD for 12 years. His major problem is freezing of gait that occurs mainly in narrow spaces and when he is engaged in further activity than walking (e.g. talking). The clinician responsible for his treatment recommends a training activity by means of a system based on sensors to be placed on the legs. The system is worn for several hours during the day, and when an episode of freezing occurs, biofeedback, via audio and an actuator on the leg, is provided to the user, to help him recover the gait. Eventually, this allows the user to learn new movement strategies to overcome the freezing episodes altogether, thereby providing a rehabilitation function. He is also requested to inform the system (pressing a button) when he takes the medication in the usual dosage, so the clinician is able to detect correlation with fluctuations and medication intake. He is also provided with a small device for telesupervision, to be left close to the telephone and easily activated with the help of his son.
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1 Fahn,S. The freezing phenomenon in parkinsonism. Adv. Neurol 67, 53-63 (1995).
2 Lamberti,P. et al. Freezing gait in Parkinson's disease. Eur. Neurol. 38, 297-301 (1997).
3 Bloem,B.R., Hausdorff,J.M., Visser,J.E., & Giladi,N. Falls and freezing of gait in Parkinson's disease: a review of two
interconnected, episodic phenomena. Mov Disord. 19, 871-884 (2004).
4 Gray,P. & Hildebrand,K. Fall risk factors in Parkinson's disease. J. Neurosci. Nurs. 32, 222-228 (2000).
5 Okuma,Y. Freezing of gait in Parkinson's disease. J. Neurol. 253 Suppl 7, VII27-VII32 (2006).
6 Hausdorff,J.M. et al. Rhythmic auditory stimulation modulates gait variability in Parkinson's disease. Eur. J. Neurosci. 26, 2369-2375 (2007).