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UDC 616.858-073
THE USE OF STATISTICAL STABILOMETRIC METHOD FOR ASSESSING POSTURAL DISORDERS IN PATIENTS WITH PARKINSON DISEASE
Rostov State Medical University, Rostov-on-Don
T.S. Kolmakova, Z.A. Goncharova, A.V. Tarakanov, N.S. Isachkina, M.A. Gelpei
Postural disorders are among the most disabling clinical symptoms of Parkinson's disease (PD). Objective: To estimate the regulation of motor activity in PD patients and their relatives via stabilography method to create a risk assessment PD algorithm. Materials and methods. Clinical and neurophysiological analysis was performed in 25 patients with PD, 9 relatives of patients and 31 people for control group without any clinical manifestations of neurological diseases. All surveyed produce static stabilometric study. The results show a significant reduction in compensatory ability to maintain balance and the main pillar in Parkinson's disease, regardless of the clinical form of the disease. Stabilometric method can detect violations of the regulation of motor activity in healthy people at risk of PD.
Key words: Parkinson's disease, Stabilometric method.
The Parkinson's disease (PD) is an irreversibly progressing neurodegenerative disease based on the predominant damage of dopaminergic neurons of substantia nigra (SN) presented in combination of hypokinesia and muscular rigidity, shivering, postural instability and a broad range of non-motor symptoms [1]. It is stated, that PD clinical manifestations are diverse and include vegetative, sensory and neuropsychic disorders along with the motor ones. At the present time, the spectrum of non-motor symptoms is considered as PD predictor having a lead of more than 10-20 years [2]. Moreover, the intensity of motor symptoms has a stronger influence on the patients' quality of life than the intensity of non-motor clinical manifestations [3].
At the late stages, the diagnosis of PD does not cause difficulties not only for neurologists, but also for the doctors of other specialties. At present, a serious problem is still the diagnostics of the disease at early stages, when the motor defect is minimally expressed and the treatment of pathology is most effective. According to the epidemiological study of Goncharova Z.A. et al. (2014), in the city of Rostov-on-Don, out of all patients with PD registered at the healthcare institutions of the city only 8,1% are diagnosed with the I stage. AT the same time, patients with the II stage constitute 41,6%, with the III stage - 40,37%. According to the authors, such a low epidemiological indicator of PD I stage frequency of occurrence is connected with the insufficient diagnostics of the current disease at the early stage [4].
The main PD manifestations include walking and postural resistance disorders which develop at a particular stage in all patients [5]. At the early disease stages, walking disorders, as a rule, do not cause any serious problems in patients, but with the PD progression and postural instability
their influence grows consistently accompanied by the appearance of "freezing', falls, which finally leads to the inevitable patient's disablement [6]. The disorder of balance function increases the possibility of falls either by standing or by moving of patients, contributes to the appearance of fractures, growth of functional dependence of patients, decreases their quality of life. Apart from the falls, postural disorders are characterized by the change of the muscle tone, which leads to the development of the flexion pose, in severe cases there can develop camptocormia - expressed bendover of the body to the front. A number of patients are characterized by the development of the Pisa syndrome, by which the body diverges in the coronary plane. Postural disorders also include microbasia, freezing during walking, propulsions [7, 8].
The appearance of modern instrumental methods of examination of walking and balance functions allows to study the peculiarities of walking and postural stability disorders at different stages of PD in more detail. One of such methods is sta-bilography combining such advantages as nonin-vasiveness, possibility of automatic processing, ability of mass use. The principle of stabilography method consists in the evaluation of human biome-chanical indicators during the process of keeping the vertical pose [9].
The keeping of balance by human is a dynamical phenomenon requiring continuous movement of the body which is the result of interaction of vestibular and visual analyzers, articular and muscular proprioception, central and peripheral nervous system. It should be noted, that the conditions of the vertical pose maintenance are characterized by a special difficulty - small bearing area, great number of turning joints and high position of the gravity center. Maintenance of the vertical pose involves high number of various reflectory
systems forming a complicated system of regulation [10].
Until the present time, there has not existed a single viewpoint on the mechanisms of postural instability development by PD.
At the moment, there is marked the accumulation of PD cases in families. By the existence of one close relative with PD, the risk of this disease increases by 2-2,5 times, while by the existence of two relatives with PD the risk grows nearly by 10 times. In this regard, the evaluation of PD risk in patients' relatives becomes topical. As PD refers to the diseases with genetic predisposition, essential is also the problem of the search of early symptoms forming the clinical picture of the disease.
Research objective: estimation of the regulation of motor activity in PD patients and their relatives via stabilography method.
Materials and methods
The research was performed on the base of the neurological department of the SBEI HPO RostSMU hospital during the period from March 2016 to November 2016. By the study there were used the data of anamnesis, medical documentation, full neurological and instrumental examination of 25 patients with PD (14 men, 11 women), 9 relatives of probands (4 men, 5 women) and 31 persons for the control group (13 men, 18 women).
The stabilographic study was performed in the laboratory of extreme physical methods of diagnostics and treatment of RostSMU. The stabilometrics was conducted in the specially equipped room with sufficient area (20 m2) to prevent acoustic orientation of patient in the space in the presence of the doctor-researcher. The patient's feet were placed on the platform according to the American position. From the moment of patient's readiness until the start of the examination there was kept the interval of not less than 20 seconds to avoid the change of parameters due to transition processes. The Romberg's test consists of three tests - maintenance of balance with open (OE) and closed (CE) eyes and the Target test (T).
In terms of the first test, the examined person had to stand in the normal position with open eyes during 52 seconds with the following task: to calculate inwardly the circles of white color appearing on the display. In the second test, the examined person stood in the normal position with closed eyes and counted sound signals. The essence of test with closed eyes consists in the fact, that the visual analyzer influence is excluded and the vertical position is retained only due to proprioception. Test T was performed in one stage with visual feedback. The examined person standing on the platform should keep the marker in the center of the target with large scale of reflection by moving the body.
The test was interrupted and started again by the appearance of distractors capable of changing the results: coughing, scratching, head turning, any speech, external audio and other signals. Upon the end of the test the examined person reported the number of circles and signals. According to the test results, there was calculated the Romberg coefficient as the relation of the area of sta-tokinesiogram in the test with closed eyes ELLS (CE) to the area of statokinesiogram in the test with open eyes ELLS (OE). Romberg coefficient = ELLS(CE)/ ELLS(OE)*100%; is used for the quantitative determination of the correlation between the visual and proprioceptive systems of balance control in the normal position.
The statistical processing was performed by means of Microsoft Office Excel 2007 (Microsoft Corp., USA). The character of data distribution was evaluated by the graphical method. The data with normal distribution were processed by paramet-rical methods of the statistical significance evaluation: Student t-test (t-test). In case of data distribution deviating from the normal one, there was used the non-parametric Mann-Whitney U test (U-test). The critical significance level by the testing of statistical hypothesis was considered 0,05. The description of characteristics with normal distribution is presented in the form of M±SD, where M - arithmetical mean, SD - standard deviation.
Results and discussion
In the analyzed sample the average age constituted 62,3±7,7 years, the stage according to the Hoehn and Yahr Rating Scale averagely constituted - 2,4±0,7. The onset of disease was observed averagely at the age of 55,9±8,6 years. The disease duration constituted from 0,5 to 15 years, the average disease duration - 6,4±4 years. The akineticorigid form of PD was diagnosed in 13 (52%) patients, the rigid-tremor form - in 12 (48%) patients.
According to the analysis of the stabilogram, the plane curve of the amplitude curve of the body fluctuation in the standing position with open eyes characterized the unsteady balance of the body by PD.
There was also discovered a significant dissociation between the clinical manifestation of postural instability and stabilometric indicators representing the state of vertical body balance.
The analysis of the stabilogram depending on the age and PD duration showed significant correlations between the age of patients and the test with OE and between the disease duration and the test with T (r=-0,4 and -0,6 respectively, p<0,05), which corresponds to the literature data. For example, in the work of Yunishchenko N.A. (2006) there is revealed the dependence of the sta-tokinesiogram with the PD duration and the stage according to the Hoehn and Yahr Rating Scale [11]. Thus, at the late PD stage the growth of walking
and postural stability disorders can be connected with the desautomatization of movement programs, progression of regulatory and neurody-namic disorders in the brain.
There was revealed a considerable difference between the stabilometry parameters in patients with PD and persons of the control group (U-test =236,5; p<0,05). The average values of tests in patients: OE - 73,8±26; CE - 61,1±27; T - 62,2±23. In the control group: OE 88,9±8,6; CE - 81,1±8,3; T -75,1±16,9. At the same time, the indexes of relatives of probands were intermediate: OE - 88,8±4,9; CE - 71,8±26,9; M - 65,8±22,9.
In the course of the current study, the patients were not differentiated according to the stages and the form of the disease due to the small sample. Supposedly, by the tremor PD form there are determined more severe disorders to the side of instability of the normal position, while by the aki-neticorigid form - its hyperstability. There should be considered the question of the diagnostic ability of stabilometry for the akineticorigid forms of PD, as the slowness and stiffness can predetermine the reduction of speed of the pressure point movement and the reduction of the statokinesiogram area [12]. Thus, in the work of Tretyakova N.A. et al. (2011) there was conducted the differential clinical and stabilometric analysis of various PD phenotypes [13]. By the tremor PD form, there was revealed the dissociation between the clinically expressed postural instability and stabilometric parameters. While in patients with the rigid disease form the obtained data reflect the disorders of statics, which indicates the necessity of further differential approach by the stabilometric analysis in patients with various clinical PD forms.
Conclusions
The method of statistic stabilometry allows to objectivate the disorders of postural functions and to evaluate there state in dynamics. The age and the disease duration significantly worsen the study indexes. By means of the stabilo-graphic method it is possible to determine the disorder of the regulation of motor activity in healthy people included into the PD risk group.
The results obtained in terms of the current study require further research by the bigger volume of sample.
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Contacts:
Corresponding author - Kolmakova Tatyana Sergeyevna, Doctor of Biological Sciences, Professor, Head of the Department of medical biology and genetics of the FSBEI HE Rostov State Medical University of the Ministry of Health of the Russian Federation, Rostov-on-Don.
344022, Rostov-on-Don, Nakhichevansky Pereu-lok, 29.
Tel.: (863) 2504200.
Email: tat_kolmakova@mail.ru
