A Modular Platform for In-plane Ground Reaction Forces Detection in a Mouse Model: Design, Development and Verification (original) (raw)
Related papers
2006
Movement and behaviour analysis is a key research area in the domain of biomedical engineering and in many other medical research domains aiming at the understanding of physiological motor and cognitive basic mechanisms. The systematic application of robotic and mechatronic technologies to realize new tools and measurement methods for quantitatively assessing motor and cognitive functions in humans as well as in animal models is gaining an increasing popularity. This paper focuses on behavioral analysis of small animal such as mice and rats, and specifically on the design, development and application of a novel system for tremor analysis in reeler mice, a very promising animal model for anatomical and behavioural traits observed in autism. Ground Reaction Force (GRF) sensing is indeed the most direct means of measuring tremor. Under the hypothesis that in-plane GRF components are directly connected to tremor, a dedicated small size, low cost, 2-axis force sensor for measuring the in-plane components of GRF was designed and developed. Special care was paid to design a mechanical structure that would allow self-aligned assembly, so that repeatability and modularity can be easily guaranteed even when combining multiple platforms for implementing a larger sensorised floor embedding multiple sensors. Preliminary testing was performed with both reeler and control (wildtype) mice. A novel measurement method was also identified, applied and verified against experimental data: first Fourier analysis was deployed to extract information due to tremor and to validate the hypothesis of a direct connection between tremor and in-plane GRFs. Secondly, a 2-nd order filter equivalent to an analogical active filter has been implemented in Matlab environment. Data analyzed and filtered highlight a peculiar spectrum frequency in Reeler mice tremor, centered at about 23 Hz. This tremor, which was never quantitavely observed and measured before,is completely absent in wildtype mice.
Validation of a new computerized system for recording and analysing drug-induced tremor in rats
Journal of Pharmacological and Toxicological Methods, 2001
Introduction: Certain drugs can induce tremor in small animals and can be used as Parkinson's disease or essential experimental tremor models. However, the use of arbitrary scales for evaluating tremor in experimental models is limited by observer subjectivity. Progress in electronics and computer science has allowed a more precise quantification of tremor. The objective of the present study was to validate a newly developed low-cost method of spectral registration and analysis of tremor in free-moving rats. Methods: Male Wistar rats, 3-4 months of age, previously placed for 5 min inside a sensor cage, were administered with different doses of eserine (0.25-1.5 mg/kg), oxotremorine (0.25-1.5 mg/kg) or harmaline (7.5-60 mg/kg). Drug-induced tremor was recorded during 10 min using a computerized system composed of force transducers, a signal conditioning circuit, a digitizing interface and a microcomputer. The signal transmitted to the computer was quantified, stored and analyzed for its amplitude and frequency by means of specific programs. Results: Tremor was induced with an amplitude that was dose-dependent for all drugs used. Tremor frequency was dose-dependent for oxotremorine and eserine, but not for harmaline. The performance of the system was compared with that of other systems described in behavioral instrumentation literature. Discussion: The present data indicate that the new system is capable of detecting the tremor induced by drugs, and that the programs used for spectral analysis allow the quantification of the amplitude and the frequency of the tremor in free-moving rats.
Neurophysiological bases of tremors and accelerometric parameters analysis
2012 4th IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob), 2012
Physiologic tremor is causedby three different generators with two frequency peaks that act together. A mechanical-reflex slower oscillator, that resemble the viscoelastic properties of muscle-joint complex and a faster oscillator that is the compound of loop reflexcomposed by the spinal loop and supraspinal reflex loop and central neurogenic oscillator. Central neurogenic tremors seem to be generated by nerve networks in the Central Nervous System (i.e. cortico-basal gangliacortical loops/olivocerebellar pathways). Such disorders are mainly represented by Essential tremor and Parkinson's tremor and are characterized by a frequency independent of reflex loop time, joint inertia, and joint stiffness. Even if tremor can be easily characterized describing its frequency, amplitude and relation with muscle, rest or activity, an universal method for movement disorder diagnosis and follow-up of the symptom is still missing. Among the technological tools for tremor analysis triaxial accelerometer are able to offer low invasiveness and high reliability. This paper introduces the neurophysiological substrate of tremor and offers a proof of concept of tremor evaluation for diagnostic support and drug-efficacy in Parkinsonian and subjects affected by essential tremor. It is achieved through a self-assembled wireless, low cost and wearable device, designed for operating in patient ecological environment.
Quantifying the importance of high frequency components on the amplitude of physiological tremor
Experimental Brain Research, 2010
The objective of this study was to determine the importance of every frequency component on total physiological tremor (PT) amplitude. We suspect that since high frequencies of PT are of lower amplitude in displacement, removing them will have little to no impact on PT amplitude. PT of the index finger was measured with a laser displacement sensor while the finger was held horizontally. Amplitude of tremor was calculated in displacement, velocity and acceleration. PT amplitude was also calculated within five frequency bands. Although displacement amplitude of oscillations within the 7.5–12.5 and 16.5–30 Hz frequency bands represent 24 and 10% of total PT oscillation amplitude, respectively, their removal reduced PT amplitude by less than 3%. Conversely, the removal of the oscillations within 1–3.5 Hz band from the PT signal reduced the amplitude of the original PT signal by 56% in displacement. This suggests that when a task to be studied involves the measurement of a reduction in tremor, focus should be on the oscillations in the 1–3.5 Hz band.
Human Tremor: Origins, Detection and Quantification
Practical Applications in Biomedical Engineering, 2013
Practical Applications in Biomedical Engineering 4 involuntary, rhythmic, oscillatory movement of a body part that can be classified in many ways, depending on its etiology, phenomenology, frequency, location and pharmacological response [2; 3]. The rhythmic characteristic of tremor around a balanced position, as the regular rhythm, amplitude and frequency make easier the identification and also the differential diagnosis of tremor, distinguishing it from other involuntary movements. The movement caused by tremor can be associated to many factors such as neurological disorders and natural processes. The latter is often referred to as physiological tremor and is present in greater or lesser degree, in all humans [2; 4]. The presence of severe tremor disorders causes many difficulties, and can also indicate the presence of diseases related to the central nervous system (CNS). However, the dividing landmark between physiological tremor and that resultant of dysfunctions is tenuous and has not been precisely established, since the changes in the CNS control that causes it can be associated to many factors. Some examples of pathological tremor, i.e. associated to neurological disorder factors, are the cerebellar, essential and parkinsonian tremor [5], and others, such as in psychogenic, orthostatic and neuropathic tremor, which are considered relatively rare in the medical literature [6]. According to phenomenology, or better, according to the circumstances in which tremor manifests it can be classified in two main types: resting tremor and action tremor [4]. The resting tremor can be observed when the body part in which it appears is not suffering the effects of gravity and the muscles are not contracted [4]. Usually, the resting tremor has the characteristic of adduction-abduction or flexion-extension. The main example of resting tremor is the parkinsonian tremor.
Experimental Brain Research, 2005
The goal of this study was accurate quantification of the amplitude of high-frequency components of physiological tremor (PT) in units of displacement, velocity, and acceleration. In addition, changes of amplitude with finger loading were compared within specific frequency bands. Index finger tremor was measured for 20 healthy subjects using a high-resolution laser, simultaneously with an accelerometer, under two conditions, unloaded and loaded (70 g). By use of an accurate filtering technique, oscillations within six predetermined frequency bands were isolated. Results showed that overall mean tremor amplitude under the unloaded condition was 0.0973 mm in displacement units, 4.525 mm s À1 in velocity units, and 301.526 mm s À2 in acceleration units. Although the mean amplitude of oscillations located within the 16.5-30 Hz band was 0.009 mm and represented only 10% of total tremor amplitude, amplitude of acceleration within the 16.5-30 Hz band was 191 mm s À2 and represented 60% of total acceleration amplitude. Mean amplitude increased significantly with loading (displacement, t=À2.67, P=0.015; velocity, t=À4.33, P=0.000; acceleration, t=À3.48, P=0.002) but the magnitude of that change was different in each frequency band and its relative importance depended on the level of signal differentiation. Velocity was the only measure that retained sensitivity to changes in amplitude with loading in the low and high-frequency components of PT. In conclusion, this study provides, for the first time, accurate quantification of the amplitude of oscillation of highfrequency components of PT. In addition, it provides clear evidence that the velocity of tremor oscillation is more suitable for detection of the impact of finger loading because it enables detection of amplitude changes in both the low and high-frequency components of PT.
Using Frequency Domain Characteristics to Discriminate Physiologic and Parkinsonian Tremors
Journal of Clinical Neurophysiology, 1999
Address correspondence and reprint requests to Anne Beuter, Cognitive Neuroscience Laboratory (WB-5110), Université du Québec à M ontréal, CP 8888, succ. Centre-ville, M ontreal, Quebec, Canada H3C 3P8. Supported by Natural Sciences and Engineering Research Council of Canada (Canada), Fonds pour la Formation de chercheurs et l'aide á la recherche (Quebec), and the Cree Board of Health and Social Services of James Bay (M ontreal).
A Review on Techniques for Tremor Recording and Quantification
Critical Reviews™ in Biomedical Engineering, 2007
Tremor is the most common movement disorder and differs from other disorders by its repetitive, stereotyped movements, with regular frequency and amplitude. The three most frequent pathological forms of it are the essential tremor (ET), the Parkinson's disease (PD) tremor, and the enhanced physiological tremor. The ET and PD tremor affect the older population mostly. Although there are cases of tremor reported since ancient times, there is currently no consensus about its causes or about its main differential characteristics. In this article, we present a review of the methods more frequently used in measurement and analysis of tremor and the difficulties encountered in the research for the identification of methodologies that allow a significant advance in the study of tremor.
Power Spectral Analysis of Tremor Induced by TRH and Oxotremorine in Mice
Annals of the New York Academy of Sciences, 1989
TRH causes various types of involuntary movements in rats or mice.'.* Many authors suggest that TRH-induced abnormal movements, such as tremor or wetdog shake, are linked with dopaminergic and cholinergic a~tivities.~ On the other hand, it is well-known that oxotremorine, a cholinergic agent, causes significant tremor in mice. In the present study, we compared the frequency and power spectrum of TRH-induced tremor with those of oxotremorine-induced tremor in mice by using new apparatus for analyzing tremor. Male mice, ddY strain, weighing 25 t o 45 g were used as experimental animals. The block diagram of apparatus for evaluation of tremor activity in mice is shown in FIGURE 1A. To avoid high voltage artifacts due to gross movements of the body, the time constant of the polygraph's preamplifier was set at 0.03 seconds. In that condition, powers under 4 Hz were markedly suppressed, whereas powers above 10 Hz remained almost unchanged. Tremor induced by TRH and oxotremorine was recorded by a capacitance transducer, and its intensity and frequency were evaluated using power arrays. In mice treated with TRH (20 mglkg, i.p.), the latency of tremor was 17.1 2 1.7 min (mean ?SE), and the duration was 20.4 i 2.2 min, whereas the frequency was 13.7 ? 0.3 Hz. In animals with oxotremorine (0.5 mglkg, i.p.), the latency was 4.3 ~t _ 0.4 min, and the duration was 18 rt 2.2 min, whereas the frequency was 12.7 t 0.3 Hz. The latter frequency, however, was significantly shifted to the lower frequency as a function of time. In TRHinduced tremor, vertical movements appeared in the same degree as horizontal movements (FIG. 1B). In oxotremorine-induced tremor, the vertical movements were few, whereas the horizontal movements were similar to those observed for TRH. The TRH-induced tremor was suppressed by haloperidol (1 mgikg) and propranolol(2 m a g) but not by phenoxybenzamine (2 mg/kg) and atropine (5 mg/ kg). On the contrary, the oxotremorine-induced tremor was inhibited by atropine but not by haloperidol or propranolol (FIG. 2).