Dr.Med., Professor L.V. Kapilevich^{1, 2}
PhD, Associate Professor K.V. Davletiyarova²
Postgraduate S.D. Korshunov²
N.A. Ovchinnikova^2
1National Research Tomsk State University, Tomsk
²National Research Tomsk Polytechnic University, Tomsk

Keywords: walking, mobility, haemodynamics, rheography, impedance plethysmography, vegetative regulation, cerebral palsy (CP).

Background. It is a matter of common knowledge that vegetative tonus secured by the blood circulation system is a key component of the movement control physiological system [1, 5]. It is the efficiency of the oxygen supply to the working muscles and removal of the vital process wastes that largely determines the movement performance efficiency [3, 7]. Vegetative support system realignments are known to be an important element of the adaptation processes in response to varying conditions, including the mobility limitations due to different musculoskeletal system disorders. It should be noted that the system realignment goes in a non-linear manner with a variety of mechanisms being involved in the process in different stages [2]. Motor skills need to be developed in a child with CP with due consideration for the functional reserves of the lower-limb blood circulation system [4, 6].

Objective of the study was to explore effects of physical loads on the lower-limb haemodynamic parameters in children with movement disorders on the whole and cerebral palsy (CP) in particular.

Methods and structure of the study. Subject to the study were 40 children, including 24 boys and 16 girls aged 8 to 12 who were split up into Study Group (SG) of those diagnosed with (mostly spastic) cerebral palsy and taking adaptation therapeutic course at the Rehabilitation Centre for Children and Adolescents with Mobility Limitations (Regional Government Budgetary Institution, CJSC, based in Seversk town); and Reference Group (RG) of 20 healthy children (12 boys and 8 girls) of the same age.

For the lower limb haemodynamics profiling purposes, we used Reo-Spectrum-2 Rheograph System designed by NeuroSoft Ltd. to obtain the rheographic indices (RI); amplitude-frequency rates (AFR); fast blood filling indices (Vmax); slow blood filling indices (Vav); diastolic indices (DIA); dicrotic indices (DIC); and venous outflow rates (VOR). Rheographic tests of the lower limbs were performed prior to and after the 10-minute walking exercises on a walking electric treadmill set at 1 km per hour.

Study results and discussion. Given in Table 1 hereunder are the lower-limb blood flow test data of the SG (CP-diagnosed) and RG (healthy) children at rest and after exercise.

Pulse blood filling indices in the CP-diagnosed group were found 3 times higher in the left thigh and moderately lower in the right thigh [versus the RG rates]. No significant differences of both of the groups were found in the pulse blood filling indices measured in the shin muscles. The pulse volume indices in the SG were found to moderately increase in the right and left thighs following the physical loads. The blood filling indices in the RG following the physical loads were notably on the rise in contrast to the SG where they were found to fall. The study tested the CP-diagnosed children with higher post-load pulse blood filling indices in thighs in contrast to the healthy children tested with higher pulse blood filling indices in shins.

The children with CP at rest showed the left and right thigh muscle AFR being 2 times higher and 1.5 times lower [than the RG values], respectively. The groups showed no significant differences in the shin muscle AFR. Following the physical loads, the SG showed rise of AFR in thighs and shins in contrast to the RG where the post-load shin muscle AFR notably sagged.

The resting blood flow rates in the large arteries in the SG were 2 times higher in the left thigh and 1.5 times lower in the right thigh versus that in the RG. No significant group differences of these rates were found in the shin muscles. After the physical loads, the thigh blood flow rates were notably on the rise in both of the groups (particularly in the right thighs), whilst only RG showed the rate rise in the shin muscles.

The resting blood flow rates in the small- and medium-sized arteries in the SG were 3 times higher in the left thigh and 1.5 times lower in the right thigh versus those in the RG. No significant differences of these rates were found in the shin muscles. After the physical loads, the shin blood flow rates were insignificantly higher in the CP (SG) group, with the rise being more expressed in the RG.

Resting peripheral vascular resistance (as verified by the DIC rates) in the SG was found to be moderately lower in the left and right thigh and higher in the left and right shin than those in the RG. After the physical loads, the healthy (RG) children were tested with lower DIC rates in every segment, whilst the SG showed significant rise of these rates in the right shin muscles.

The diastolic indices (DIA) and venous outflow rates (VOR) indicative of the venous system condition were notably lower in the CP-diagnosed (SG) group than those in the RG. Following the physical loads, these rates were found to increase in the thigh muscles in the both groups, albeit the venous outflow rates in the RG were significantly higher. The post-exercise venous outflow in the shin muscles was found restricted in the both groups, albeit the effect was much more expressed in the SG.

The blood flow dynamic disorders in the children with CP are likely to be due to the generally lower motor activity (hypokinesia) which is known to cut down the oxygen demand and the waste product excretion rates of the body and, hence, ease loads on the blood circulation system. These body conditions are associated with the circulating blood volume being on the fall and the blood volumes being redistributed in favour of the upper part of the body. Therefore, this condition is of detriment for the capillary blood circulation and walls of small-sized vessels and may result in asthenic effects and vascular and autonomic dysfunction.

Conclusion. The study data demonstrates that the children with cerebral palsy experience the lower-limb peripheral blood circulation system dysfunctions. At rest, the condition manifests itself mostly in the thigh area as verified by the asymmetrically growing pulse blood filling and blood flow rates with the falling venous outflow rates. In the post-exercise tests, the children with cerebral palsy were tested with higher pulse blood filling indices, blood flow volumes and rates mostly in the thigh zone in contrast to the healthy children who showed these rates growing mostly in the shin zone. The post-exercise venous outflow was found to be more restricted in the children with cerebral palsy.

Therefore, the children with cerebral palsy were diagnosed with low vegetative support of the distal limb segments, whilst the proximal segments were found to retain some functional reserve. This finding gives the reasons to recommend mostly thigh muscles being loaded and shin muscles being released in the adaptive motor skills stereotyping process.

Table 1. Reographic rates indicative of the regional blood flow in the lower limbs,`Х ±m 

* Group difference significance rate; # post-load variation significance rate (p<0.05).

Corresponding author: kapil@yandex.ru

Abstract

Impedance plethysmography tests were used to obtain the regional blood flow profiling data (prior and after physical exercises) in children with mobility limitations – particularly caused to cerebral palsy (CP). The study diagnosed the subject CP-sick children with low vegetative support of the distal limb segments, whilst the proximal segments were found to retain some functional reserve. This finding gives the reasons to recommend mostly the thigh muscles being loaded and the shin muscles being released in the adaptive motor skills stereotyping process.

The study was performed with financial support from the Russian Humanitarian Research Foundation (RHRF) #15-16-70005

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