title: The filtering of the posturographic signals shows the age related features.
abstract: Lower frequencies of slow oscillations of the posturographic signals can be removed using high-pass filtering. This procedure releases postural reflexes possessing higher frequencies and lower amplitude range. Mutual dependence between the x and y components of posturographic signals was analyzed using principal component analysis (PCA). The posturographic signals of old patients with idiopathic gait disturbance were compared with the control group of similar age and with younger patients. There was also the analysis of the influence of the eyes state (open versus closed) and the head position (normal or bent back). The statistically significant differences in the mutual dependence between x and y components between the groups of patients were analyzed using MANOVA. The significant differences were observed mainly in the range of filter frequencies f = 0.1-1.5 Hz and f = 2.2-5.5 Hz with a maximum effect at approximately 4-5 Hz. A detailed post-hoc analysis is also presented. The differences in the higher frequency range suggest the main disturbance to be connected with the spinal reflexes. Visual and vestibular support appear insufficient for postural stability control in the idiopathic gait disturbance group. The results suggest that idiopathic gait disturbance is the final stage of the aging process of postural system.
authors.affiliation: Laboratory of Vision Science and Optometry, Faculty of Physics, Adam Mickiewicz University of Poznań, Umultowska Street 85, 61-614 Poznań, Poland.
authors.forename: Krzysztof Piotr
authors.initials: KP
authors.lastname: Michalak
authors.affiliation: Laboratory of Vision Science and Optometry, Faculty of Physics, Adam Mickiewicz University of Poznań, Umultowska Street 85, 61-614 Poznań, Poland.
authors.forename: Anna
authors.identifier: 0000-0003-2401-4135
authors.initials: A
authors.lastname: Przekoracka-Krawczyk
authors.affiliation: Laboratory of Vision Science and Optometry, Faculty of Physics, Adam Mickiewicz University of Poznań, Umultowska Street 85, 61-614 Poznań, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Nawrot
authors.affiliation: Polish Mother's Memorial Hospital-Research Institute, Rzgowska Street 281/289, Łódź, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Woźniak
authors.affiliation: Neurology Clinic, Klinikum Lippe, Rintelner Street 85, 32657 Lemgo, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Vieregge
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000503:physiopathology*; D011187:Posture / Q000502:physiology*