Keywords
multiple sclerosis - relapsing-remitting - postural balance - dizziness - quality
of life
Introduction
Multiple sclerosis (MS) is an autoimmune, chronic, and demyelinating disease of the
central nervous system (CNS). It is more common in young adults and has unpredictable,
complex, and heterogeneous evolution due to the involvement of various pathophysiological
processes.[1]
[2] It is characterized by an inflammatory reaction that damages the myelin sheaths
of the axons of the brain and spinal neurons, causing demyelination and the appearance
of a vast picture of signs and symptoms.[2]
The diagnosis of MS is established based on clinical history and on physical and complementary
examinations; there is no pathognomonic marker for the diagnostic definition of the
disease. The diagnostic criteria that highlight the temporal and spatial distribution
of the disease[3] should be supplemented with the results of magnetic resonance imaging (MRI) of the
brain and the spinal cord, when necessary.[4] The evolution of MS follows certain clinical patterns characterized by relapses
and progression, classified as relapsing-remitting, primary progressive, secondary
progressive, and progressive-relapsing.[1]
Relapsing-remitting multiple sclerosis (RRMS) is the most common pattern, reaching
85.0% of cases. Symptoms occur in the form of clinically well-defined relapses. Recovery
is variable; 40.0% of relapses result in persistent neurological deficiencies and
patients may accumulate progressive disability.[5]
Physical disabilities during the evolution of MS over time can be classified using
the expanded disability status scale (EDSS) in eight functional systems: pyramidal,
cerebellar, brainstem, sensory, vesical and/or intestinal, visual, mental, and other
functions.[6] The score ranges from zero to 10; zero corresponds to a normal neurological examination,
and ten to death due to MS. Scores > 4.5 are greatly influenced by the ability of
the individual to walk, especially the ability to walk certain distances and the need
for aids, such as unilateral, bilateral, or wheelchair support.[7]
Due to the variable distribution of demyelination in the CNS, patients with MS may
present with disorders of coordination, sensitivity, strength, and body balance.[8] Abnormalities of body balance are described in 78.0% of patients with MS,[9]
[10] accompanied by a high incidence of falls[8]
[11]
[12]
[13] over a period of 2 to 6 months in > 50.0% of cases.[8]
[14]
[15]
[16] The high prevalence of changes in body balance in patients with MS reinforces the
relevance of a comprehensive diagnostic investigation of postural control, since this
symptom may have peripheral vestibular origin, regardless of signs of CNS impairment,
enabling relevant therapeutic interventions.[17]
[18]
The present study is justified by the importance of setting up a functional evaluation
protocol to show objective signs of impairment of postural control in patients with
MS, allowing to customize the appropriate therapeutic conduct according to the findings
in each case, when necessary. The hypothesis for the present study is that patients
with MS, even without postural instability and who did not meet the clinical criteria
for physical disability in the medical evaluation using the EDSS, may present with
objective signs of postural control impairment.
The overall objective of the present study is to evaluate postural control in patients
with RRMS. The specific objectives are to compare the results of the body balance
of patients with RRMS those of a control group and with reference values, checking
whether there is an association between the fall risk over time in the disease state,
the functional ability, the intensity, and the self-perception of the influence of
the dizziness on the quality of life, the postural instability, and the practice of
physical activity of the patient.
Method
The present analytical cross-sectional study, conducted in patients with RRMS[4] under regular follow-up in the outpatient clinic of demyelinating diseases of the
discipline of Neurology in the outpatient clinic of demyelinating diseases of the
Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, was approved
by the Research Ethics Committee under number 3114893. The individuals were informed
about the procedures performed and signed the Informed Consent Form, enabling their
participation, as well as subsequent analysis and dissemination of the results.
The present study was conducted in the discipline of Otology and Otoneurology of the
Department of Otorhinolaryngology and Head and Neck Sugery, Universidade Federal de
São Paulo.
The experimental group was composed of patients with a diagnosis of RRMS, selected
from January 2017 to July 2018 during the weekly follow-up at the outpatient clinic
of demyelinating diseases of the discipline of Neurology, outpatient clinic of demyelinating
diseases of the Department of Neurology and Neurosurgery, Universidade Federal de
São Paulo. The inclusion criteria were neurological medical diagnosis of RRMS,[4] EDSS score ≤ 6 points, and age between 18 and 65 years old.
The control group consisted of healthy individuals from the community, caregivers
of patients, and students, and was homogeneous in terms of age, gender, height, and
body mass index (BMI) in relation to the experimental group. The inclusion criteria
for the control group were absence of a history of vestibular, auditory, body imbalance
and/or headache symptoms, and absence of symptoms or of a diagnosis of neurological
disease.
Patients in exacerbation (relapse) of demyelination in the previous 8 weeks, presenting
with other neurological conditions not associated with MS, and under corticoid pulse
therapy in the previous 3 months were excluded from the experimental group. In both
groups, individuals who presented with inability to understand and meet simple verbal
commands, with inability to remain independently in the orthostatic position, with
severe or uncompensated visual impairment with the use of corrective lenses, with
orthopedic disorders that result in limitation of movement or require the use of prostheses
in the lower limbs, with a history of otological past, who had used medications that
affect the vestibular system, and who had performed rehabilitation of body balance
in the previous 6 months were excluded.
The evaluation consisted of anamnesis, application of the Dizziness Handicap Inventory
(DHI) in the Brazilian Portuguese version, visual vertigo analog scale (VVAS), and
evaluation of postural control through static posturography.
Anamnesis was performed through a detailed interview, with the application of a questionnaire
focused on the clinical history of the patients, including information on complaints
of dizziness, postural instability, physical activity practice, and medications in
use.
The DHI questionnaire on quality of life,[19] in the Brazilian Portuguese version,[20] was applied to assess the self-perception of disability imposed by dizziness. Twenty-five
questions evaluated the physical, emotional, and functional aspects. The questionnaire
was read by the researcher to all participants, who answered the questions with “yes,”
“no” or “sometimes.” For each “yes” answer, four points were assigned; for “no,” zero
points; and for “sometimes,” two points. The higher the score, the greater the loss
in quality of life.[19] Self-perception of dizziness was considered mild between zero and 30 points; moderate
between 31 and 60; and severe between 61 and 100 points.[21]
The self-perception of the intensity of dizziness was evaluated by the VVAS, consisting
of a graduated line from zero to 10, in which zero corresponded to the absence of
dizziness, and 10 to maximum dizziness.[22]
Postural control evaluation was performed with static posturography (Tetrax IBS, Sunlight
Medical Ltd, Tel Aviv, Israel), which consists of a computer program, a platform with
four integrated but independent plates (A-B-C-D), which capture the variations of
weight distribution, handrails, and foam mattresses.
The participants were barefoot, with their toes and heels resting on the indicative
design of the platform, fixed their gaze on a target in front of them and kept their
posture upright and stable, with their arms extended along the body for 32 seconds,
in each of the 8 sensory conditions. The examiner remained close to the participant
during the procedure.
The sensory conditions evaluated were: 1) Stable surface, face forward, eyes open
(NO); 2) Stable surface, face forward, eyes closed (NC); 3) Unstable surface, face
forward, eyes open (PO); 4) Unstable surface, face forward, eyes closed (PC); 5) Stable
surface, head with 45° rotation to the right, eyes closed (HR); 6) Stable surface,
head with 45° rotation to the left, eyes closed (HL); 7) Stable surface, head tilted
30° back, eyes closed (HB); and, 8) Stable surface, head tilted 30° forward, eyes
closed (HF).
The sensory condition in a stable surface, face forward and eyes open, which is in
the neutral position, analyzes the visual, somatosensory, and vestibular systems;
and the condition on a stable surface, face forward and eyes closed limits vision
effect, testing the somatosensory and vestibular systems; and the condition of unstable
surface, face forward and eyes open limits the effect of proprioception by stimulating
the visual and the vestibular systems; the conditions of stable surface, head rotated
45° to the right or to the left and eyes closed also eliminate the vision and stimulate
the vestibular system; and the conditions stable surface, head tilted 30° backward
or forward and eyes closed eliminate the vision and stimulate the vestibular and cervical
systems.[23]
The posturography measured the variations of the vertical force exerted by the heels
and toes, allowing the characterization of the oscillation of the body according to
the displacement of the pressure center. Tetrax IBS evaluated the indices of stability,
weight distribution, synchronization of right/left postural oscillation and of toes/heels,
frequencies F1 to F8, and frequency bands F1, F2–F4, F5–F6, F7–F8 of postural oscillation,
in each of the 8 sensory conditions, and the Fall Risk Index.[23]
[24]
The stability index mathematically indicated the overall stability and the ability
to compensate for postural modifications and evaluated the number of oscillations
on the four platforms, according to body weight; the higher the score, the greater
the instability.[23]
The weight distribution index compares the weight distribution on each of the four
plates. The theoretically lowest limit is zero, with 25% of the weight distributed
on each plate. In normal individuals, a value between 4 and 6% is expected. The higher
the score, the greater the difficulty in maintaining balance. Very low values, close
to zero, indicate postural stiffness, which is common in compensation mechanisms.[23]
The right/left and heel/toe synchronization postural oscillation indices measured
the coordination between the lower limbs and symmetry in weight distribution. For
each condition, six synchronizations were measured: heels and toes of each foot (AB,
CD), two heels and toes of both feet (AC, BD), and the two diagonals, between the
heel of one foot and the contralateral toes (AD, BC). The synchronization indices
AB, CD, AD and CB are negative, and the BD and AC are positive. Values with inverted
signals suggest excessive postural oscillation; low values indicate impairment; high
values may be due to postural stiffness or to intentional simulation of lateral oscillation.[23]
The frequencies of postural oscillation vary in a spectrum between 0.01 and 3.0 Hz
and were measured by Fourier transformation, a mathematical treatment that indicates
the intensity of body oscillation at different frequencies.
Tetrax IBS subdivided the spectrum of postural oscillation into 4 frequency bands:
low (F1), < 0.1 Hz; low-medium (F2–F4), between 0.1 and 0.5 Hz; medium-high (F5–F6),
between 0.5 and 1.0 Hz; and high (F7–F8), > 1.0 Hz.
Each postural oscillation frequency band enhances the use of a certain postural subsystem.
Prevalence of postural oscillations in the low frequency band suggests postural control
and integrity of the vestibulovisual-otolytic systems; in the low-medium frequency
band, it suggests peripheral vestibular dysfunction, physical fatigue or exhaustion,
and alcohol intoxication; in the medium-high frequency band, it suggests somatosensory
reactions mediated by the motor system of the lower limbs and the spine; and, in the
high frequency band, it suggests CNS impairment.[23]
The fall risk index, expressed as a percentage, weighs the results of the Tetrax IBS
parameters in the eight sensory conditions. It can vary between zero and 100; a value
between zero and 36% is considered as mild risk (marked in green on the Tetrax IBS
chart); a value between 37 and 58%, moderate risk (in yellow); and between 59 and
100%, high risk (in red). The higher the score, the higher the fall risk.
The individual performance of the patient in the analysis of all parameters in the
eight sensory conditions allowed to identify the altered sensory systems involved
in maintaining postural control,[23] according to the following characteristics: a) Substantial difference in weight
or desynchronization of one of the feet from the other, consistent in all positions,
would indicate deficiency in one of the lower extremities, as a function of an orthopedic
problem or neurological dysfunction; b) Low and consistent performance in sensory
conditions HR, HL, HF and HB in relation to NO, NC, PO and PC conditions would indicate
cervical vestibular disorders; c) Low and consistent performance in the values of
the Stability Index and increased postural oscillation in different frequency bands
would indicate impairment in the vestibular and somatosensory systems or CNS impairment.
Consistently low performance in weight distribution and synchronization indices of
postural oscillation points in the direction of orthopedic problems; d) Consistently
poor results in all conditions and parameters suggest a generalized lower limb problem
or severe CNS disorder; e) Consistently poor performance in all sensory conditions
in the values of the Stability Index and increase of postural oscillation in different
frequency bands, with normal or close to normal results, in all conditions in the
weight distribution and synchronization of postural oscillation indices, often indicates
intentional simulation of body oscillation; f) Inconsistent responses in some sensory
conditions, with others without change, imply test repetition; g) Low performance
in a specific postural oscillation frequency band could be related to one of the following
changes: F1) visual dysfunction; F2–4) vestibular dysfunction, mainly peripheral;
F5–6) somatosensory dysfunction; and, F7–8) central vestibular dysfunction; h) Changes
in all frequency bands would indicate widespread disturbance of the postural system,
provided that the weight distribution and synchronization indices of the postural
oscillation also show poor results; i) Increased body oscillation in the low-medium
frequency band (F2–F4), altered weight distribution to compensate for loss of balance,
relatively worse performance in sensory condition PC, discrepancy between performance
in sensory conditions HR and HL related to lateralization of vestibular dysfunction,
normal synchronization and normal stability, if vestibular dysfunction is well compensated,
suggest peripheral vestibular system dysfunction; j) Increased and abnormal body oscillation
in the high frequency band (F7–F8), low synchronization in general and, in particular,
in the stressful vestibular sensory condition PC and altered performance in general
stability and weight distribution suggest central vestibular system dysfunction.
The statistical analysis was initially performed in a descriptive way through the
average, median, minimum and maximum values, standard deviation (SD), and absolute
and relative frequencies (percentage). The inferential analyses employed to confirm
or refute evidence found in the descriptive analysis were:
-
Mann-Whitney[25] to compare the characteristics of quantitative nature between groups (experimental
and control); and the Fall Risk Index (%), according to time of disease (≤10 years,
>10 years), EDSS (≤ 3 and >3 points), complaint of postural instability, and the practice
of physical activity;
-
Kruskal-Wallis[25] to compare the fall index, according to the degree of fall risk (mild, moderate,
or high); and the Fall Risk Index (%), according to dysfunction in Tetrax IBS (peripheral,
central, or absent);
-
Pearson chi-squared test, Fisher exact test, or its extension[26] to compare the groups (experimental and control), according to characteristics of
a qualitative nature.
In all conclusions of the inferential analyses, the level of Alpha significance equal
to 5.0% was used. The data were entered into Microsoft Excel 2010 for Windows (Microsoft
Corporation, Redmond, WA, USA) spreadsheets for proper information storage. Statistical
analyses were performed with the statistical program R version 3.3.2. (R Foundation,
Vienna, Austria).
Results
Of the 352 patients referred to the Outpatient Clinic of Demyelinating Diseases of
the Discipline of Neurology, outpatient clinic of demyelinating diseases of the Department
of Neurology and Neurosurgery, Universidade Federal de São Paulo, 106 consecutive
patients met the inclusion criteria for the experimental group and were asked by telephone
contact to perform the procedure; and 55 did not show up on the scheduled day or refused
to participate in the trial. The final sample of the experimental group consisted
of 51 patients diagnosed with RRMS and 28 healthy individuals from the control group.
[Table 1] shows the demographic data and clinical characteristics of the two groups.
Table 1
Descriptive values and comparative analysis of demographic data and clinical characteristics
of experimental and control groups
|
Demographics and clinical characteristics
|
|
RRMS (n = 51)
|
CO (n = 28)
|
p-value
|
|
Gender
|
Female
|
34
|
66.7%
|
23
|
82.1%
|
0.142 [b]
|
|
Male
|
17
|
33.3%
|
5
|
17.9%
|
|
|
Age (years old)
|
Median
|
39.0
|
29.0
|
0.148 [a]
|
|
Minimum
|
18.0
|
18.0
|
|
|
Maximum
|
65.0
|
58.0
|
|
|
Weight (kg)
|
Median
|
68.6
|
63.5
|
0.085 [a]
|
|
Minimum
|
40.8
|
41.6
|
|
|
Maximum
|
129.2
|
101.7
|
|
|
Height (cm)
|
Median
|
167.0
|
163.5
|
0.240 [a]
|
|
Minimum
|
149.0
|
130.0
|
|
|
Maximum
|
190.0
|
187.0
|
|
|
BMI (kg/m2)
|
Median
|
24.9
|
23.5
|
0.241 [a]
|
|
Minimum
|
17.2
|
16.3
|
|
|
Maximum
|
40.8
|
60.2
|
|
|
Physical activity
|
Yes
|
17
|
33.3%
|
14
|
50.0%
|
0.147 [a]
|
|
No
|
34
|
66.7%
|
14
|
50.0%
|
|
|
Postural instability
|
Yes
|
32
|
62.7%
|
−
|
−
|
|
|
No
|
19
|
37.3%
|
−
|
−
|
|
|
Fall
|
Yes
|
18
|
35.3%
|
|
|
|
|
No
|
33
|
64.7%
|
|
|
|
|
Time of disease (years)
|
Median
|
12.0
|
−
|
|
|
Minimum
|
1.0
|
−
|
|
|
Maximum
|
20.0
|
−
|
|
|
EDSS
|
Median
|
2.0
|
−
|
|
|
Minimum
|
0.0
|
−
|
|
|
Maximum
|
6.0
|
|
|
Abbreviations: CO, control; EDSS, Expanded Disability Status Scale; RRMS, relapsing-remitting
multiple sclerosis.
a Mann-Whitney Test.
b Pearson chi-squared test.
* Statistically significant value at the level of 5% (p < 0.05).
[Table 2] shows the results of the DHI and of the VVAS of the experimental group.
Table 2
Descriptive values of the Dizziness Handicap Inventory and of the visual vertigo analogue
scale of the experimental group
|
Assessments
|
RRMS (51)
|
|
Physical DHI
|
Median
|
6.0
|
|
Minimum
|
0.0
|
|
Maximum
|
28.0
|
|
Functional DHI
|
Median
|
2.0
|
|
Minimum
|
0.0
|
|
Maximum
|
30.0
|
|
Emotional DHI
|
Median
|
0.0
|
|
Minimum
|
0.0
|
|
Maximum
|
36.0
|
|
Total DHI
|
Median
|
10.0
|
|
Minimum
|
0.0
|
|
Maximum
|
94.0
|
|
DHI degree (n, %)
|
Asymptomatic
|
20
|
39.2%
|
|
Light
|
20
|
39.2%
|
|
Moderate
|
08
|
15.7%
|
|
Severe
|
03
|
5.9%
|
|
VVAS
|
Median
|
3.0
|
|
Minimum
|
0.0
|
|
Maximum
|
10.0
|
Abbreviations: DHI, Dizziness Handicap Inventory; RRMS, relapsing-remitting multiple
sclerosis; VVAS, visual vertigo analogue scale.
[Table 3] shows the descriptive values and comparative analysis of the weight distribution
index and the general stability index of the experimental and control groups in the
eight sensory conditions in Tetrax IBS. The weight distribution index was higher in
the experimental group under sensory conditions head with rotation of 45° to the right
on firm surface (HR) and head tilted 30° back on firm surface (HB), with a statistically
significant difference. The experimental group presented a higher overall stability
index than the control group in all the conditions evaluated, with a statistically
significant difference.
Table 3
Descriptive values and comparative analysis of the weight distribution index and the
general stability index in the eight conditions of the Tetrax Interactive Balance
System (Tetrax IBS) of the experimental and control groups
|
|
Weight distribution index
|
|
Stability Index
|
|
|
|
RRMS (n = 51)
|
CO (n = 28)
|
p-value
|
RRMS (n = 51)
|
CO (n = 28)
|
p-value
|
|
NO
|
Median
|
4.98
|
5.00
|
0.862
|
15.53
|
10.99
|
< 0.001[*]
|
|
Minimum
|
1.30
|
1.69
|
|
7.46
|
5.38
|
|
|
Maximum
|
11.83
|
11.43
|
|
58.36
|
18.97
|
|
|
NC
|
Median
|
5.04
|
4.63
|
0.197
|
23.86
|
16.61
|
< 0.001[*]
|
|
Minimum
|
1.35
|
0.94
|
|
8.11
|
6.66
|
|
|
Maximum
|
13.30
|
10.82
|
|
77.02
|
24.98
|
|
|
HR
|
Median
|
6.07
|
4.33
|
0.048[*]
|
21.26
|
13.93
|
< 0.001[*]
|
|
Minimum
|
1.76
|
0.86
|
|
9.02
|
6.25
|
|
|
Maximum
|
13.98
|
11.60
|
|
84.65
|
24.17
|
|
|
HL
|
Median
|
5.27
|
4.69
|
0.219
|
21.73
|
14.24
|
< 0.001[*]
|
|
Minimum
|
2.14
|
1.25
|
|
9.24
|
5.96
|
|
|
Maximum
|
12.84
|
12.54
|
|
76.34
|
21.39
|
|
|
HB
|
Median
|
5.67
|
4.06
|
0.007[*]
|
23.81
|
15.67
|
< 0.001[*]
|
|
Minimum
|
2.11
|
1.31
|
|
11.21
|
6.40
|
|
|
Maximum
|
15.86
|
13.83
|
|
91.31
|
23.28
|
|
|
HF
|
Median
|
5.83
|
5.37
|
0.351
|
21.43
|
14.60
|
< 0.001[*]
|
|
Minimum
|
1.90
|
2.27
|
|
11.36
|
6.75
|
|
|
Maximum
|
15.00
|
14.34
|
|
62.54
|
27.06
|
|
|
PO
|
Median
|
5.37
|
5.04
|
0.846
|
25.38
|
16.20
|
< 0.001[*]
|
|
Minimum
|
1.57
|
1.91
|
|
12.64
|
10.34
|
|
|
Maximum
|
14.38
|
10.88
|
|
60.25
|
29.85
|
|
|
PC
|
Median
|
4.56
|
4.68
|
0.846
|
38.56
|
21.49
|
< 0.001[*]
|
|
Minimum
|
0.81
|
1.64
|
|
17.19
|
12.17
|
|
|
Maximum
|
13.26
|
10.82
|
|
87.60
|
39.36
|
|
Abbreviations: CO, control; HB, eyes closed, head tilted 30° backward, on a firm surface;
HF, eyes closed, head tilted 30° forward, firm surface; HL, eyes closed, head rotated
45 ° to the left, and on a firm surface; HR, eyes closed, head rotated 45 ° to the
right, on a firm surface; NC, eyes closed, firm surface; NO, eyes open, firm surface;
PC, eyes closed on an unstable surface; PO, eyes open on an unstable surface; RRMS,
relapsing-remitting multiple sclerosis.
Mann-Whitney test.
* Statistically significant value at the level of 5% (p < 0.05).
[Table 4] presents the descriptive values and comparative analysis of the synchronization
indices of the experimental and control groups in the eight sensory conditions in
Tetrax IBS. There was no statistically significant difference between the groups in
the condition of eyes closed on a firm surface (NC), in the synchronization between
the toes and the heel of the left foot (AB) and the toes of the right foot and the
toes of the left foot (BD); in the conditions with the head rotated 45° to the left
on a firm surface (HL), and eyes closed on an unstable surface (PC), the synchronization
between the toes of the right foot and the toes of the left foot (BD); on the condition
with the head tilted 30° backward, firm surface (HB), the synchronization between
the toes and the heel of the left foot (AB), or between the toes and the heel of the
right foot (CD) and between the toes of the right foot and the toes of the left foot
(BD); and the condition with the head tilted 30° forward, firm surface (HF), the synchronization
between the toes and the heel of the left foot (AB).
Table 4
Descriptive values and comparative analysis of the synchronization indices in the
eight conditions of the Tetrax Interactive Balance System (Tetrax IBS) of the experimental
and control groups
|
|
AB
|
|
CD
|
|
AC
|
|
BD
|
|
AD
|
|
BC
|
|
|
|
RRMS
|
CO
|
p-value
|
RRMS
|
CO
|
p-value
|
RRMS
|
CO
|
p-value
|
RRMS
|
CO
|
p-value
|
RRMS
|
CO
|
p-value
|
RRMS
|
CO
|
p-value
|
|
|
(n = 51)
|
(n = 28)
|
|
(n = 51)
|
(n = 28)
|
|
(n = 51)
|
(n = 28)
|
|
(n = 51)
|
(n = 28)
|
|
(n = 51)
|
(n = 28)
|
|
(n = 51)
|
(n = 28)
|
|
|
NO
|
Median
|
−831.93
|
−869.70
|
0.219
|
−869.03
|
−889.19
|
0.461
|
635.67
|
706.72
|
0.967
|
767.99
|
836.80
|
0.137
|
−851.53
|
−872.92
|
0.616
|
−907.23
|
−872.21
|
0.053
|
|
Minimum
|
−981.16
|
−985.59
|
|
−991.18
|
−978.90
|
|
−155.32
|
−102.29
|
|
−57.16
|
153.01
|
|
−987.84
|
−967.41
|
|
−986.73
|
−960.79
|
|
|
Maximum
|
−80.67
|
−205.42
|
|
−286.10
|
−97.60
|
|
969.14
|
868.03
|
|
976.72
|
951.92
|
|
−260.84
|
−402.23
|
|
−231.33
|
−430.22
|
|
|
NC
|
Median
|
−861.06
|
−920.75
|
0.031
[*]
|
−904.04
|
−909.57
|
0.207
|
727.43
|
734.20
|
0.539
|
820.52
|
881.93
|
0.028
[*]
|
−882.64
|
−903.96
|
0.566
|
−914.99
|
−906.88
|
0.330
|
|
Minimum
|
−989.79
|
−986.57
|
|
−989.26
|
−985.72
|
|
−430.96
|
80.00
|
|
19.06
|
−86.13
|
|
−979.75
|
−976.66
|
|
−981.65
|
−972.19
|
|
|
Maximum
|
677.38
|
−744.95
|
|
423.88
|
−645.89
|
|
941.34
|
931.69
|
|
976.43
|
980.81
|
|
−420.06
|
−189.09
|
|
−596.03
|
13.92
|
|
|
HR
|
Median
|
−876.54
|
−908.20
|
0.062
|
−894.34
|
−901.94
|
0.870
|
738.60
|
721.62
|
0.862
|
847.50
|
891.55
|
0.068
|
−893.49
|
−918.07
|
0.406
|
−916.89
|
−900.69
|
0.601
|
|
Minimum
|
−980.03
|
−989.37
|
|
−986.67
|
−988.27
|
|
−651.09
|
77.94
|
|
−195.12
|
631.09
|
|
−972.49
|
−985.92
|
|
−982.85
|
−981.92
|
|
|
Maximum
|
503.68
|
−592.61
|
|
312.76
|
−385.32
|
|
957.94
|
952.65
|
|
964.19
|
989.21
|
|
−180.66
|
−666.18
|
|
−158.16
|
−444.97
|
|
|
HL
|
Median
|
−841.20
|
−842.40
|
0.412
|
−894.48
|
−877.52
|
0.927
|
543.93
|
660.27
|
0.518
|
797.93
|
837.88
|
0.045
[*]
|
−856.35
|
−879.37
|
0.239
|
−885.47
|
−886.18
|
0.902
|
|
Minimum
|
−977.42
|
−977.71
|
|
−990.63
|
−977.93
|
|
−251.77
|
−336.19
|
|
−177.39
|
636.60
|
|
−976.60
|
−972.81
|
|
−981.66
|
−975.71
|
|
|
Maximum
|
12.53
|
−289.86
|
|
304.68
|
74.38
|
|
904.66
|
923.64
|
|
965.00
|
981.06
|
|
−16.89
|
−319.57
|
|
−355.88
|
−277.62
|
|
|
HB
|
Median
|
−865.04
|
−921.48
|
0.013
[*]
|
−876.86
|
−936.90
|
0.043
[*]
|
687.18
|
761.27
|
0.190
|
776.86
|
883.82
|
0.021
[*]
|
−888.12
|
−899.12
|
0.190
|
−914.64
|
−896.72
|
0.935
|
|
Minimum
|
−986.93
|
−991.37
|
|
−989.69
|
−985.22
|
|
−463.45
|
212.95
|
|
−147.46
|
−7.34
|
|
−967.96
|
−976.39
|
|
−985.41
|
−985.07
|
|
|
Maximum
|
196.12
|
−236.91
|
|
9.39
|
−336.87
|
|
929.99
|
926.26
|
|
983.71
|
987.48
|
|
202.11
|
−631.60
|
|
−250.41
|
−356.97
|
|
|
HF
|
Median
|
−839.36
|
−916.92
|
0.004
[*]
|
−907.61
|
−909.67
|
0.406
|
634.93
|
708.75
|
0.239
|
819.95
|
864.23
|
0.055
|
−863.04
|
−876.48
|
0.727
|
−910.74
|
−866.07
|
0.103
|
|
Minimum
|
−989.09
|
−980.24
|
|
−991.23
|
−991.11
|
|
−727.61
|
92.29
|
|
−6.13
|
635.11
|
|
−987.67
|
−956.12
|
|
−987.28
|
−966.70
|
|
|
Maximum
|
287.60
|
−304.73
|
|
789.54
|
−711.61
|
|
968.96
|
917.98
|
|
974.39
|
973.07
|
|
−81.40
|
−534.96
|
|
−304.63
|
−581.76
|
|
|
PO
|
Median
|
−750.41
|
−799.16
|
0.095
|
−811.91
|
−824.82
|
0.854
|
642.21
|
806.13
|
0.081
|
663.79
|
757.91
|
0.320
|
−911.61
|
−918.77
|
0.927
|
−926.95
|
−947.02
|
0.239
|
|
Minimum
|
−986.52
|
−963.23
|
|
−977.45
|
−983.70
|
|
−332.84
|
285.97
|
|
−748.72
|
87.70
|
|
−982.37
|
−990.61
|
|
−992.12
|
−992.88
|
|
|
Maximum
|
625.59
|
−334.90
|
|
47.40
|
−161.11
|
|
977.85
|
959.51
|
|
972.45
|
958.72
|
|
−115.90
|
−484.03
|
|
−50.64
|
−581.46
|
|
|
PC
|
Median
|
−776.46
|
−836.07
|
0.054
|
−852.33
|
−890.31
|
0.095
|
745.61
|
771.60
|
0.148
|
755.21
|
848.09
|
0.048
[*]
|
−935.67
|
−936.29
|
0.325
|
−943.43
|
−952.41
|
0.362
|
|
Minimum
|
−978.68
|
−984.79
|
|
−981.96
|
−972.60
|
|
−164.12
|
312.42
|
|
19.00
|
339.71
|
|
−989.30
|
−984.93
|
|
−989.98
|
−993.51
|
|
|
Maximum
|
519.49
|
−565.85
|
|
549.51
|
−373.60
|
|
977.82
|
964.21
|
|
967.98
|
980.78
|
|
−633.73
|
−761.35
|
|
−629.05
|
−815.00
|
|
Abbreviations: AB, index of synchronization between platforms related to toes and
the heel of the left foot; AC, index of the synchronization between the right and
the left heels; AD, index of synchronization between the left heel and the toes of
the right foot; BC, index of synchronization between the toes of the left foot, and
the heel of the right foot; BD, index of synchronization between the toes of the right
foot and the toes of the left foot; CD, index of synchronization between toes and
the heel of the right foot; CO, control; HB, eyes closed, head tilted 30° backward,
on a firm surface; HF, eyes closed, head tilted 30° forward, firm surface; HL, eyes
closed, head rotated 45° to the left, and on a firm surface; HR, eyes closed, head
rotated 45° to the right, on a firm surface; NC, eyes closed on firm surface; NO,
eyes open, firm surface; PC, eyes closed on an unstable surface; PO, eyes open on
an unstable surface; RRMS, relapsing-remitting multiple sclerosis; Mann-Whitney test.
* Statistically significant at the 5% level (p < 0.05).
[Table 5] shows the descriptive values and the comparative analysis of postural oscillation
frequency bands (F1, F2–F4, F5–F6, F7–F8) of the experimental and control groups in
the 8 sensory conditions in Tetrax IBS. In the conditions of closed eyes on firm surface
(NC); head with rotation of 45° to the right on firm surface (HR); head with rotation
of 45° to the left on firm surface (HL); head tilted 30° backward on firm surface
(HB); head tilted 30° forward on firm surface (HF); and closed eyes on unstable surface
(PC), the experimental group presented higher values than those of the control group
in all frequency bands, with a statistically significant difference. In the conditions
of open eyes on a firm surface (NO), and of open eyes on an unstable surface (PO),
the experimental group presented higher values than those of the control group in
the frequency bands F2–F4, F5–F6, and F7–F8, with a statistically significant difference.
Table 5
Descriptive values and comparative analysis of postural oscillation frequency bands
(F1, F2–F4, F5–F6, F7–F8) in the eight conditions of the Tetrax Interactive Balance
System (Tetrax IBS) of the experimental and control groups
|
|
BAND F1
|
|
BAND F2-F4
|
|
BAND F5-F6
|
|
BAND F7-F8
|
|
|
Condition
|
|
RRMS (n = 51)
|
CO (n = 28)
|
p-value
|
RRMS (n = 51)
|
CO (n = 28)
|
p-value
|
RRMS (n = 51)
|
CO (n = 28)
|
p-value
|
RRMS (n = 51)
|
CO (n = 28)
|
p-value
|
|
NO
|
Median
|
16.02
|
12.80
|
0.143
|
7.54
|
5.50
|
< 0.001[*]
|
3.22
|
2.39
|
0.002[*]
|
0.49
|
0.41
|
0.030[*]
|
|
Minimum
|
6.68
|
5.71
|
|
2.91
|
2.75
|
|
1.12
|
1.09
|
|
0.24
|
0.18
|
|
|
Maximum
|
49.92
|
22.59
|
|
21.14
|
8.43
|
|
13.12
|
3.89
|
|
1.44
|
0.69
|
|
|
NC
|
Median
|
14.57
|
10.01
|
0.029[*]
|
10.46
|
8.35
|
0.004[*]
|
4.60
|
3.06
|
< 0.001[*]
|
0.70
|
0.53
|
0.018[*]
|
|
Minimum
|
4.55
|
5.07
|
|
4.52
|
4.31
|
|
1.57
|
0.93
|
|
0.30
|
0.17
|
|
|
Maximum
|
45.38
|
25.08
|
|
43.95
|
12.74
|
|
14.16
|
5.07
|
|
3.02
|
0.95
|
|
|
HR
|
Median
|
15.41
|
10.99
|
0.004[*]
|
10.31
|
6.59
|
< 0.001[*]
|
4.07
|
2.49
|
< 0.001[*]
|
0.72
|
0.38
|
< 0.001[*]
|
|
Minimum
|
4.49
|
4.67
|
|
4.26
|
4.56
|
|
1.32
|
0.90
|
|
0.28
|
0.19
|
|
|
Maximum
|
44.90
|
32.05
|
|
49.10
|
11.12
|
|
12.59
|
3.92
|
|
3.23
|
0.91
|
|
|
HL
|
Median
|
13.28
|
10.08
|
0.010[*]
|
9.89
|
6.25
|
< 0.001[*]
|
3.96
|
2.58
|
< 0.001[*]
|
0.66
|
0.44
|
< 0.001[*]
|
|
Minimum
|
4.89
|
5.16
|
|
4.30
|
3.52
|
|
1.56
|
1.17
|
|
0.29
|
0.18
|
|
|
Maximum
|
36.52
|
29.70
|
|
32.81
|
9.89
|
|
11.14
|
4.31
|
|
2.87
|
0.85
|
|
|
HB
|
Median
|
16.74
|
10.79
|
0.009[*]
|
11.22
|
7.45
|
< 0.001[*]
|
4.23
|
2.72
|
< 0.001[*]
|
0.74
|
0.47
|
< 0.001[*]
|
|
Minimum
|
5.66
|
2.44
|
|
4.32
|
4.10
|
|
1.63
|
0.90
|
|
0.38
|
0.19
|
|
|
Maximum
|
42.94
|
34.44
|
|
51.58
|
11.63
|
|
15.21
|
4.20
|
|
2.56
|
0.86
|
|
|
HF
|
Median
|
15.49
|
12.83
|
0.024[*]
|
11.16
|
7.33
|
< 0.001[*]
|
4.22
|
2.74
|
< 0.001[*]
|
0.71
|
0.53
|
0.001[*]
|
|
Minimum
|
2.63
|
3.87
|
|
2.62
|
3.50
|
|
2.02
|
1.27
|
|
0.34
|
0.19
|
|
|
Maximum
|
69.70
|
25.27
|
|
28.06
|
14.35
|
|
11.05
|
5.14
|
|
3.13
|
1.00
|
|
|
PO
|
Median
|
20.69
|
21.23
|
0.559
|
9.19
|
6.31
|
< 0.001[*]
|
5.00
|
3.43
|
< 0.001[*]
|
0.81
|
0.54
|
0.001[*]
|
|
Minimum
|
7.27
|
10.83
|
|
4.70
|
4.18
|
|
2.36
|
2.12
|
|
0.25
|
0.35
|
|
|
Maximum
|
64.57
|
37.22
|
|
38.55
|
8.96
|
|
11.97
|
5.91
|
|
1.98
|
1.01
|
|
|
PC
|
Median
|
27.69
|
17.24
|
0.005[*]
|
15.18
|
9.89
|
< 0.001[*]
|
7.27
|
3.68
|
< 0.001[*]
|
1.30
|
0.79
|
< 0.001[*]
|
|
Minimum
|
6.41
|
8.08
|
|
6.45
|
6.87
|
|
2.59
|
1.93
|
|
0.54
|
0.37
|
|
|
Maximum
|
90.91
|
40.96
|
|
38.10
|
20.18
|
|
17.62
|
6.94
|
|
3.98
|
1.36
|
|
Abbreviations: CO, control; F1, F2-F4, F5-F6, F7-F8, postural oscillation frequency
bands; HB, eyes closed, head tilted 30° backward, on firm surface; HF, eyes closed,
head tilted 30° forward, on firm surface; HL, eyes closed, head 45° to the left, on
firm surface; HR, eyes closed, head 45° to the right, on firm surface; NC, eyes closed,
on firm surface; NO, eyes open, on firm surface; PC, eyes closed on an unstable surface;
PO, eyes open on an unstable surface; RRMS, relapsing-remitting multiple sclerosis.
Mann-Whitney test.
* Statistically significant value at the level of 5% (p < 0.05).
[Table 6] presents the descriptive values and the comparative analysis of the fall risk index
of the experimental and control groups in Tetrax IBS. The experimental group had a
higher Fall Risk Index than the control group, with a statistically significant difference.
Table 6
Descriptive values and comparative analysis of the Fall Risk Index (%) in the Tetrax
Interactive Balance System (Tetrax IBS) of the experimental and control groups
|
|
Fall Risk Index (%)
|
|
|
|
RRMS
|
CO
|
Total
|
p-value
|
|
n
|
51
|
28
|
79
|
< 0.001[*]
|
|
Average
|
52.51
|
10.86
|
37.75
|
|
|
Median
|
42.00
|
7.00
|
26.00
|
|
|
Minimum
|
4.00
|
2.00
|
2.00
|
|
|
Maximum
|
100.00
|
28.00
|
100.00
|
|
|
Standard deviation
|
33.48
|
8.19
|
33.82
|
|
Abbreviations: CO, control; RRMS, relapsing-remitting multiple sclerosis.
Mann-Whitney Test.
* Statistically significant value at the level of 5% (p < 0.05).
In the control group, the 28 (100.0%) individuals had a mild degree fall risk in Tetrax
IBS. [Table 7] shows the distribution of patients in the experimental group according to the degree
of fall risk in Tetrax IBS. The proportion of patients at moderate and high fall risk
was significantly higher in the experimental group compared with the control group
(p < 0.001).
Table 7
Distribution of patients according to the degree of fall risk in the Tetrax Interactive
Balance System (Tetrax IBS) in the experimental group
|
Degree of Fall Risk
|
|
|
|
Light
|
Moderate
|
HIgh
|
Total
|
p-value
|
|
n
|
22
|
8
|
21
|
51
|
< 0.001[*]
|
|
Average
|
21,0
|
43.5
|
89.0
|
52.5
|
|
|
Median
|
16.0
|
43.0
|
94.0
|
42.0
|
|
|
Minimum
|
4.0
|
38.0
|
64.0
|
4.0
|
|
|
Maximum
|
36.0
|
52.0
|
100.0
|
100.0
|
|
|
Standard deviation
|
10.7
|
4.6
|
12.5
|
33.5
|
|
Kruskal-Wallis test.
* Statistically significant value at the level of 5% (p < 0.05).
The general analysis of postural performance identified, in the experimental group,
26 (51.0%) patients with main pattern of impairment of the vestibular, visual and/or
somatosensory systems of peripheral type, namely, 15 (29.5%) cases of the vestibular
system, 8 (15.7%) of the vestibular and somatosensory systems, 2 (3.9%) of the vestibular,
visual and somatosensory systems, 1 (1.9%) of the vestibular and visual, and 11 (21.6%)
with vestibular, visual and/or somatosensory impairment of the central type, with
7 (13.7%) of the vestibular system, 4 (7.8%) of the vestibular system with cervical
impairment, and 14 (27.4%) without alterations. In the control group, no change was
found in the maintenance of postural control in the 28 (100.0%) individuals evaluated.
[Table 8] shows the type of dysfunction as peripheral, central or absent in relation to the
Fall Risk Index in Tetrax IBS in the experimental group. Patients with peripheral
and central dysfunction had a higher fall risk than patients without dysfunction,
with a statistically significant difference (p < 0.001). There was no statistically significant difference (p = 0.295) between patients with peripheral and central dysfunction in relation to
the fall risk index.
Table 8
Distribution of patients according to the type of dysfunction: peripheral, central
or absent, and Fall Risk Index in the Tetrax Interactive Balance system (Tetrax IBS)
in the experimental group
|
Type of dysfunction in
|
Fall Risk Index (%)
|
|
|
Tetrax IBS
|
n
|
Average
|
Median
|
Minimum
|
Maximum
|
Standard deviation
|
p-value
|
|
Peripheral
|
26
|
62.8
|
58.0
|
26.0
|
100.0
|
26.9
|
< 0.001[*]
|
|
Central
|
11
|
76.9
|
94.0
|
34.0
|
100.0
|
27.4
|
|
|
Absent
|
14
|
14.1
|
14.0
|
4.0
|
30.0
|
6.0
|
|
|
Total
|
51
|
52.5
|
42.0
|
4.0
|
100.0
|
33.5
|
|
Kruskal-Wallis test.
* Statistically significant value at the level of 5% (p < 0.05).
[Table 9] shows the distribution of patients according to the time of disease, EDSS score,
symptoms of dizziness, postural instability, physical activity practice, DHI and VVAS
in relation to the Fall Risk Index of Tetrax IBS in the experimental group. There
was no statistically significant difference (p = 0.932) between the fall risk index of the experimental group and time of disease
≤ 10 years (24 cases [47.1%]) or > 10 years (27 cases [52.9%]). Patients in the experimental
group with EDSS > 3 points (14 [27.5%]) had a higher fall risk than those with EDSS
≤ 3 points (37 [72.5%]), with a statistically significant difference (p = 0.003). There was a positive correlation between the fall risk index and the total
DHI score (s = 0.380; p = 0.006) and the VVAS (s = 0.348; p = 0.012), when estimating the Spearman correlation coefficient in the experimental
group. There was no relationship between the fall risk index and the complaint of
dizziness (p = 0.192), the complaint of postural instability (p = 0.148), and the practice of physical activity (p = 0.706).
Table 9
Distribution of patients according to the time of disease, score on the expanded disability
status scale, postural instability, physical activity practice, Dizziness Handicap
Inventory, and visual vertigo analogue scale in relation to the Fall Risk Index in
the Tetrax Interactive Balance system (Tetrax IBS) in the experimental group
|
Fall Risk Index (%)
|
|
|
n
|
Average
|
Median
|
Minimum
|
Maximum
|
Standard deviation
|
p-value
|
|
Time of disease
|
|
|
|
|
|
|
|
|
≤ 10 years
|
24
|
54.3
|
39.0
|
4
|
100.0
|
33.8
|
0.932
|
|
> 10 years
|
27
|
50.9
|
44.0
|
6
|
100.0
|
33.7
|
|
|
Total
|
51
|
52.5
|
42.0
|
4
|
100.0
|
33.5
|
|
|
EDSS
|
|
|
|
|
|
|
|
|
≤ 3
|
37
|
43.7
|
36.0
|
4
|
100.0
|
30.9
|
0.003[*]
[a]
|
|
> 3
|
14
|
75.7
|
87.0
|
18
|
100.0
|
29.4
|
|
|
Total
|
51
|
52.5
|
42.0
|
4
|
100.0
|
33.5
|
|
|
Postural instability
|
|
|
|
|
|
|
|
|
Yes
|
32
|
57.2
|
45.0
|
14.0
|
100.0
|
31.70
|
0.148
|
|
No
|
19
|
44.5
|
36.0
|
4.0
|
100.0
|
35.71
|
|
|
Physical activity
|
|
|
|
|
|
|
|
|
Yes
|
17
|
57.8
|
46.0
|
14.0
|
100.0
|
33.0
|
0.706
|
|
No
|
34
|
49.9
|
39.0
|
4.0
|
100.0
|
33.9
|
|
|
Correlation analyses
|
|
n
|
p
-
value
|
r
|
|
|
DHI
|
51
|
0.006[*]
[c]
|
0.380
|
|
|
VVAS
|
51
|
0.012[*]
[c]
|
0.348
|
|
Abbreviations: DHI, Dizziness Handicap Inventory; EDSS, Expanded Disability status
Scale; VVAS, visual vertigo analog scale.
a Mann-Whitney test.
c Spearman(s) correlation test.
* statistically significant value at the level of 5% (p < 0.05).
Discussion
In the present study, the postural control of patients with RRMS was evaluated by
static posturography with Tetrax IBS. The group of patients with RRMS had a predominance
of women, with a median age of 39.0 years old, which is in line with other authors,
who reported a higher occurrence of the condition in women and young adults.[5]
Patients with RRMS presented a mild degree in the total DHI score, identifying a mild
impact of dizziness on functional, physical, and emotional well-being.[20]
[27] The EDSS also demonstrated low functional disability in patients with RRMS.
Postural instability was reported in 62.7% of the cases, and 35.3% of the evaluated
patients reported falls. Body balance disorders were described in 78.0% of patients
with MS.[9]
[10] Postural instability is considered one of the most disabling symptoms of the disease,
as it generates negative effects on mobility and independence, leading to injuries,
falls, and, consequently, impacting on the quality of life.[28] Postural control, often impaired in MS patients, is a complex skill based on the
sensory integration of visual, somatosensory, and vestibular information in the brainstem.[29] Thus, the importance of a diagnostic method that evaluates this information individually
becomes evident. Static posturography with Tetrax IBS uses different parameters and
procedures from other types of posturographies, which makes it difficult to compare
the results quantitatively with those from other devices.
The group of patients with RRMS showed higher values of the weight distribution index
in Tetrax IBS only in two sensory conditions on a stable surface with closed eyes:
in the head rotation to the right and in the head backward inclination, characterizing
irregular weight distribution in the platform plates. Change in weight distribution
index, predominantly in closed-eye sensory conditions, was described in 58% of the
patients with MS.[30] No studies were found in the literature on posturography weight distribution index
in Tetrax IBS in RRMS.
The overall stability index of patients with RRMS in Tetrax IBS showed increased values
in relation to controls in all eight sensory conditions, revealing postural control
inability. Reduced overall stability was also described in the four evaluated sensory
conditions – with open and closed eyes, on a stable surface, and on an unstable surface
– in cases of MS, when compared with controls, in Tetrax IBS.
Regarding the control group, the patients with RRMS presented on Tetrax IBS a reduction
in the synchronization indices of the postural oscillation: between the right toes
and the left toes in four of the eight sensory conditions, and an increase in the
synchronization index of the postural oscillation between the toes and the right or
left heel in three sensory conditions, characterizing incoordination between the lower
limbs and asymmetry in weight distribution. No studies were found in the literature
that evaluated the postural oscillation synchronization indices in RMSS.
Patients with RRMS showed greater postural oscillation in Tetrax IBS than the control
group in six of the eight sensory conditions evaluated in all frequency bands and
in two of the sensory conditions in all frequency bands, with the exception of the
low-frequency band. Postural performance without alteration is characterized by greater
postural oscillation at low frequency (F1), suggesting integrity of the vestibular
visual and otolithic systems. Each postural oscillation frequency band enhances the
use of a certain functional subsystem. When the low-frequency oscillation does not
maintain body balance effectively, the oscillation in the low-medium band (F2–F4)
prevails, suggesting peripheral vestibular dysfunction; and/or in the middle-high
band, suggesting somatosensory reactions; and/or in the high band, indicating CNS
impairment.[23] One study identified greater postural oscillation in the frequencies F2, F4, and
F5 in patients with MS in Tetrax IBS compared with healthy individuals, and all altered
cases presented clinical or imaging signs, indicating brainstem injury.[30]
In Tetrax IBS, the group of patients with RRMS showed higher fall risk values compared
with the control group, as well as a higher proportion of patients with moderate and
high fall risk. In agreement with this finding, just over a third of the number of
RRMS cases reported at least one episode of fall during the course of the disease.
Patients with peripheral or central dysfunction in Tetrax IBS had a higher fall risk
than patients without abnormalities, while the fall risk was similar in cases with
peripheral and central dysfunction.
In patients with MS, the incidence of falls is considered high, and its prevalence
can vary from 31.0 to 63.0%,[8]
[14]
[16]
[28]
[31] often resulting in a decrease in functional capacity due to the fear of new falls,
present in ∼ 63.5 to 69.0% of patients with MS.[14]
[28]
[32] Postural control depends on the integration of visual, somatosensory, vestibular
systems and adequate motor responses, which are often impaired in patients with MS,
contributing to increase the fall risk.[33]
The analysis of postural performance identified in most patients with RRMS the pattern
of peripheral dysfunction, showing changes in the vestibular; vestibular and somatosensory;
vestibular, visual and somatosensory; and vestibular and visual systems, in descending
order of prevalence, and, with a lower occurrence, the pattern of central dysfunction,
indicating changes in the vestibular and/or cervical systems. Studies using different
types of posturographies also reported the impairment of different systems involved
in maintaining body balance in patients with RRMS.[18]
[34]
[35]
[36]
[37]
[38]
Postural instability is greater in more challenging sensory conditions, reducing the
support base, suppressing visual or vestibular information and/or altering the proprioceptive
system in patients with RRMS.[39]
[40] Even in the sensory condition of open eyes and stable surface, using all sensory
inputs, two thirds of the total number of patients with MS present abnormal postural
performance, which can reach 82.0% of cases when there is disturbance of one of the
sensory information.[29]
There was a correlation between the fall risk index and the EDSS, of ≤ 3 or > 3 points,
in patients with RRMS. The EDSS is used by the neurologist to assess the neurological
disability of patients with MS; scores > 4.5 are greatly influenced by the ability
to walk; therefore, the higher the EDSS score, the higher the fall risk.[14]
[41] No studies were found in the literature on the fall risk measured by static posturography
and by the EDSS in patients with RRMS. However, there is a positive relationship between
static and dynamic posturography parameters and the EDSS.[38]
[42] Important postural imbalance at dynamic posturography and low functional disability
in patients with MS indicate that this examination is a valuable method of disease
monitoring.[18]
There was no correlation between the fall risk index and time of disease ≤ 10 years
or > 10 years in the group with RRMS. Studies evaluating the fall risk index measured
by a posturography and the time of disease were not found in the literature. Some
authors have described a positive correlation between the time of disease and the
overall body performance score by means of dynamic posturography in patients with
MS.[43]
In patients with RRMS, there was a positive correlation between the Fall Risk Index
and the score of the DHI and VVAS quality of life questionnaires, demonstrating the
relevance of the DHI and the VVAS in the assessment of the fall risk in patients with
RRMS and justifying its use in evaluation protocols. The reliability and validity
of the DHI in patients with MS have been demonstrated in previous studies.[29]
[44] The DHI was considered a good predictor of fall in cases of MS with and without
falls, and the questionnaire score was 31.0% higher in the group with reported falls,
with the physical and functional aspects being the most impaired.[29] The impact of dizziness and/or imbalance on the functional, physical, and emotional
well-being of patients with MS was demonstrated with the DHI score when compared with
healthy individuals.[45] No research was found in the literature that evaluated the Fall Risk Index and the
VVAS.
There was no relationship between the Fall Risk Index, the complaint of postural instability,
and the practice of physical activity in the group with RRMS, and more than one-third
of the sample practiced physical activity with nonspecific exercises. The practice
of physical activity in patients with MS should be performed after assessment and
individual counseling, considering the severity of the disease, the type of MS, age,
the degree of disability and of functional disability.[46]
[47]
Similar to the findings regarding RRMS in Tetrax IBS posturography, other posturographic
evaluations were also able to identify changes in body balance, even in RRMS without
complaint of postural instability and with a low degree of functional disability in
the EDSS, in the clinical evaluation.[37]
[39]
[40]
Conclusion
Patients with RRMS may present inability to maintain postural control due to general
instability, desynchronization and increased postural oscillation at frequencies that
suggest deficiencies in the vestibular, visual, and somatosensory systems; fall risk
was related to the state of functional disability and to the intensity and self-perception
of the influence of dizziness on the quality of life of the patient.
