Background/Aim. Postural impairments and gait disorders in Parkinson's disease (PD) affect limits of stability, impaire postural adjustment, and evoke poor responses to perturbation. In the later stage of the disease, some patients can suffer from episodic features such as freezing of gait (FOG). Objective gait assessment and monitoring progress of the disease can give clinicians and therapist important information about changes in gait pattern and potential gait deviations, in order to prevent

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... concomitant falls. The aim of this study was to propose a method for identification of freezing episodes and gait disturbances in patients with PD. A wireless inertial sensor system can be used to provide follow-up of the treatment effects or progress of the disease. Methods. The system is simple for mounting a subject, comfortable, simple for installing and recording, reliable and provides high-quality sensor data. A total of 12 patients were recorded and tested. Software calculates various gait parameters that could be estimated. User friendly visual tool provides information about changes in gait characteristics, either in a form of spectrogram or by observing spatiotemporal parameters. Based on these parameters, the algorithm performs classification of strides and identification of FOG types. Results. The described stride classification was merged with an algorithm for stride reconstruction resulting in a useful graphical tool that allows clinicians to inspect and analyze subject's movements. Conclusion. The described gait assessment system can be used for detection and categorization of gait disturbances by applying rule-based classification based on stride length, stride time, and frequency of the shank segment movements. The method provides an valuable graphical interface which is easy to interpret and provides clinicians and therapists with valuable information regarding the temporal changes in gait. Apstrakt Uvod/Cilj. Poreme aji hoda i ravnoteže kod bolesnika sa Parkinsonovom boleš u (PD) uklju uju i poreme aje stabilnosti, održavanja ravnoteže prilikom hoda i nemogunost adekvatne reakcije na iznenadne perturbacije. U kasnijim fazama bolesti neki bolesnici razvijaju i epizode motornog bloka, odnosno "frizing" tokom hoda. Objektivno pra enje i merenje karakteristika hoda i promena obrasca hoda tokom progresije bolesti mogu pomo i klini arima jer ukazuju na promene koje bi dovele do padova i ugrozile bolesnika. Cilj rada bio je razvoj metode koja bi identifikovala ovakve epizode kod bolesnika sa Parkinsonovom bolesti. Razvijeni beži ni sistem sa senzorima mogao bi se koristiti za posmatranje efekata terapije ili progresije bolesti. Metode. U radu je prikazan sistem za objektivnu procenu obrasca hoda. Koriš enjem beži nog senzorskog sistema koji koristi akcelerometre, žiroskope i senzore sile, mogu e je dobiti procenu parametara hoda, ali i identifikovati "frizing" epizode karakteristi ne za PD. Uz pomo ovog sistema snimljeno je 12 bolesnika, te je na osnovu snimljenih signala razvijen novi softverski alat koji omogu ava pra enje parametara hoda. Rezultati. Na osnovu dužine koraka, trajanja koraka i frekvencije pokreta, razvijen je algoritam za klasifikaciju tipova koraka i uo avanje promena frekvencija pokreta tokom hoda. Prikaz rezultata ovog sistema je dat kroz primer jednog bolesnika. Zaklju ak. Opisani sistem za procenu hoda može biti koriš en za kategorizaciju poreme aja hoda kroz posmatranje promena u dužini i trajanju koraka, kao i frekvencija segmenata noge. Razvijeni metod omogu ava iliustrativni prikaz i grafi ki interfejs koji je jednostavan za interpretaciju i omogu ava dobijanje informacija koje klini arima mogu ukazati na trenutne promene u obrascu hoda. Klju ne re i: parkinsonova bolest; hod, poreme aji, neurološki; bolest, progresija; biomedicinsko inženjerstvo. Strana 810 VOJNOSANITETSKI PREGLED Volumen 71, Broj 9 Djuri -Jovi i DM, et al. Vojnosanit Pregl 2014; 71(9): 809-816.