AIP Conference Proceedings 2344, 050006 (2021); https://doi.org/10.1063/5.0047217 2344, 050006
© 2021 Author(s).
Analysis of quantitative EEG (QEEG) parameters on post-stroke patients undergoing static bicycle and mirror combination therapy
Cite as: AIP Conference Proceedings 2344, 050006 (2021); https://doi.org/10.1063/5.0047217 Published Online: 23 March 2021
Hasballah Zakaria, Rudi Setiawan, and Adre Mayza
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Analysis of Quantitative EEG (QEEG) Parameters on Post- Stroke Patients Undergoing Static Bicycle and Mirror
Combination Therapy
Hasballah Zakaria
1, a), Rudi Setiawan
1 b), and Adre Mayza
1, , c)1School of Electrical Engineering and Informatics, Bandung Institute of Technology (ITB), Ganesa 10, Bandung 40119, West Java, Indonesia
Neurology Department and Cluster of Medical Technology IMERI, Faculty of Medicine, Universitas Indonesia, Jl. Salemba Raya No 6, Central Jakarta 10430 Indonesia
Corresponding author: a)[email protected]
b)[email protected], c)[email protected]
Abstract. Stroke causes neurological disorders such as reduced muscle motor skills, as well as cognitive, visual, and coordination functions, significantly. The reduced level of independence and mobility of a person can affect their quality of life. Previous research used static bicycles or mirrors for stroke therapy. This work combined both static bicycle and mirror therapy for post-stroke patients. This study aimed to find quantitative EEG parameters that can be used to characterize neurological change. The expected decrease in the average relative power of delta and theta then increased alpha and beta. Twelve post-stroke patients and twelve healthy subjects were given 2 tasks: imaginary (motor imagery) and action (motor execution). The electrodes were placed on 8 points with 10-20 localization principle rules. Data were analyzed and tested using linear regression and paired t. The result showed that static bicycle and mirror combination therapy affects a subject group of right stroke patients than a subject group of left stroke patients. When given imaginary session (motor imagery), in relative power of delta-band frequency of right stroke patients decreased by -18.65 ± 4.9% (p
= 0.0001) and action session (motor execution) by -11.23 ± 6.1% (p = 0.0035), while average relative power of theta frequency band only decreased significantly by -6.03 ± 6.4% (p = 0.0429) an imaginary session. Then, this therapy also succeeded in enhancement relative power of alpha frequency band when given imaginary session, i.e 5.45 ± 4.2% (p = 0.0161) and action session, i.e 6.92 ± 4.6% (p = 0.0024). Furthermore, the relative power of the beta frequency band also increased when given an imaginary session by 19.23 ± 9.1% (p = 0.0026) and action session by 7.29 ± 7.5% (p = 0.0194).
In conclusion, relative power, amplitude, and time (latency) of P300 and C3 to C4 ratio indicated improved health data, especially for right stroke patient subjects during therapy.
Keywords: Mirror, Combination Therapy, Post-Stroke Patients, QEEG, Static Bicycle.
INTRODUCTION
Based on Riskesdas in 2007, approximately 2.5% of the total number of stroke survivors in Indonesia died, and the remaining 97.5% experienced a mild or severe disability (post-stroke) [1]. Experienced stroke attacks can bear a neurological disorder such as reduced motor skills and muscled limbs, cognitive, visual, and coordination significantly. The reduced level of independence and mobility of a person can affect life quality [2]. The primary objective of rehabilitation in medical and health is the capability to recover some physical, sensory or mental patients with reduced or loss due to an illness or injury [4]. Through rehabilitation efforts, it is expected to restore the motor and cognitive skills of stroke patients.
The primary purpose of using a static bicycle for rehabilitation is to restore damaged motor capability. Improved movement capability, balance, and running performance are some of the application targets in cycling to rehabilitation
movement functions. Using static bicycle therapy with feedback (work, symmetry, speed, and workload) also positively affected the patient's ability to walk [4]. Besides static bicycle therapy, there is mirror therapy, which is often used for stroke patients. Mirror neuron therapy is a therapy for stroke patients by involved a mirror neuron system located in cerebral cortical that is useful for the healing competence of hands and mouth movements, which is also commonly called Mirror Visual Feedback (MVF) therapy [5].
However, both static bicycle and mirror therapy are still used separately, and few are analyzed the effect of administering them using measured quantification methods. One approach that can show an excellent therapeutic outcome assessment is using a Quantitative Electroenchelpalograph (QEEG) parameters. Therefore, this research has designed a therapy device derived from a combination of static bicycle and mirror that is also combined with neurofeedback to analyze therapy results from stroke patients using QEEG parameters.
RELATED WORKS
Research [6] has aimed to prove the effectiveness of home cycling training in 16 stroke patients for 4-6 months with hemiparesis (with the ability to walk more than 10 m, with supervision and assistance). This study has been successfully demonstrated that cycling therapy can expand mobility capacity in post-stroke patients, even after 6 months since a stroke. In another subsequent study [7], the aim was to analyze the initial effects of cycling for 3 weeks on the balance and motion performance of 10 chronic stroke patients who started rehabilitation less than 30 days after hospitalization care. After 3 weeks of therapy using a static bicycle, there has been an increase in balance and action in the group (using cycling therapy), which is higher than another group (14 sub-acute stroke patients, only did conventional therapy). This therapy has shown that early cycling exercises in the sub-acute phase of stroke can improve patients' balance and motor capability.
In addition, there is a study [8], which has aimed to determine the effect of static cycle exercise for increasing maximal oxygen volume (VO2 max) in post-stroke patients. That research was conducted in one group pre and post- test design. The number of samples was 8 patients in the Moewardi Regional General Hospital, Surakarta. A difference test was done between before and after treatment using the Wilcoxon rank test, then obtained a value p = 0.012 (<0.05) and showed a significant difference. Researchers concluded that the provision of static bicycle training affects the enhancement in maximal oxygen volume (VO2 max) of post-stroke subjects.
Another result study [9] has analyzed neuroplasticity in the primary sensory-motor cortex using mirror neuron therapy. After several days of therapy, it was observed that the left hand of stroke subjects who used a mirror turned out to show better test results compared with stroke patients who did not use mirror therapy. In addition, based on the analysis before and after using mirror therapy, the right dorsal and left ventral pre-motor cortex, the primary sensory- motor cortex, and the supplementary motor area of patients were activated. Therefore, this mirror therapy can affect the neural network and rearranged motion skills by observing the left hand from the mirror's illusionary movement.
Previous studies have found that the dominant Human Mirror Neuron System activity is a sensory-motor cortex area in the mu-band frequency of the EEG signal. Nerves in the immediate sensory-motor area indicated an increased amplitude of the EEG signal at 8-13 Hz (mu-band frequency) [10][11][12]. However, some studies reveal that mu- spectrum, aside from being in the alpha-band frequency range, can also be observed at beta-band frequency [13][14].
According to research, mirror neurons are sign activated by EEG activity at alpha/beta frequencies when the subject has or just imagined a movement of images without movement [15]. In addition, other studies also obtained results that the mu appeared significantly at points C3, CZ, and C4 electrodes during various movements compared with non-motion conditions [16][17]. Other research results have also shown that EEG power in mu-band frequency recorded on left and right hemispheres in the sensory-motor cortex appeared when observing human movements, but there is no response activity through observing the movement of inanimate objects, such as bounce ball [11].
METHODS
In this research, the tools and materials used are Starstim 5G Neuroelectrics (EEG), a static bicycle and mirror combination therapy device, gel for electrodes, computer, the open vibe (software for recording of EEG signals and Matlab 2016b (software for signal processing).
The recorded therapy data (EEG) of stroke patient subjects was conducted at the Mandiri Center and Neuro Rehabilitation Clinic, located in Lebak Bulus, South Jakarta, Indonesia, within ± 2 weeks, from 31 October 2019 to 14 November 2019. Therapeutic data from volunteer subjects were taken in wake-up and sit down conditions. There are around 17 subjects of stroke patients who have been willing to take this treatment. However, after observed data
recording, the 5 data of subjects were excluded from the dataset group, then only 12 datasets of stroke patient subjects that final analyzed. It is also known that the age range of stroke patients, both right and left, is the age range of 41-80 years. In this study, comparative therapy data were also taken from subjects of healthy people. Data was collected in Bandung, with 12 healthy subjects who were willing to be a volunteer. Healthy subjects were gathered from the Bandung Institute of Technology (ITB) students and Indonesia University of Education (UPI) students. The age range of healthy subjects is 21-50 years.
The recorded EEG data used StarStim Neuroelectric EEG wireless (Bluetooth) with 500 Hz sampling frequency.
EEG electrodes' placement is at F3, F4, C3, CZ, C4, P3, Pz, P4, and Ref, which used 10-20 localization principle rules. Retrieval of data recorded before and during therapy. During therapy, divided 2 task sessions, namely the first session with action command (motor execution) and the second session with an imaginary command (motor imagery), each command was carried out for 5 minutes. This study used a therapeutic tool that has been designed by a combination of static bicycles and mirrors. This tool provided training in static pedaling motion that rotated counter- clockwise and gave effect to mirror neurons' movement intention. The design and results of the therapy device are shown in Fig. 1.
FIGURE 1. The therapy device of static bicycle and mirror combination (a) design (b) result.
From Fig.1, a stroke therapy device has been designed with a combination of static bicycles and a mirror. This tool has a height of 41 cm, a length of 35.5 cm, and a width of 10.3 cm. The description of using a therapeutic device is shown in Fig.2.
FIGURE 2. Overview when the subject is given a combination therapy of a static bicycle and mirror.
At this therapy device, parameters are measuring the distance of the user's body to a device using an ultrasonic sensor and an indicator of the cycle during therapy based on an infrared sensor. There are 3 steps of EEG recording.
The first record of EEG subjects is before therapy for 5 minutes. Second, EEG subjects recording given an action
session (motor execution) for 5 minutes. Last, the third recording is done during an imaginary session (motor imagery) for 5 minutes. There are 2 sessions implementation, both action, and imaginary, are guided by audio-stimulus, which is given commands with a duration of around 5 minutes. The audio consisted of 20 repetition segments, with time- division per session for 15 seconds. In each repetition consisted of 10 seconds of pedaling and 5 seconds to stop at once as rest. The repetitions are repeated continuously 20 times in 5 minutes when the audio command is turned on.
The audio contained task "pedal" for cycling and "rest" to stop for resting time, and end of the session, there will be a task "done" which has finished for a therapy session.
The first segmentation signal is taken for 5 minutes. It was then filtered by Band Pass Filter (BPF) that only took a frequency range of 0.5-30 Hz, which removed the gamma signal in EEG recording to analyze the P300 amplitude.
Next, the filtered digital signal data are resegmented for 11 seconds, consisting of a 1-second baseline resting and 10 seconds as pedaling. Therefore, the 11-second data segmentation from 5-minutes data recording resulted in 20 repetition segmentations. So, it can write in a mathematical equation that will be like the following equation (1):
>
1...@
, >0...11@);
, ,
(c s tS s q tS
v (1)
Where v is EEG signal after segmentation, s is the number of segmentation, and tS is the time of segmentation. If u (c, t) represented the EEG signal in time function t with the number of channels c = [1 ... p], and a signal is divided into 11 seconds per segment. It has written in a mathematical equation be like equation (1). In the next stage, 20 data segmentation for each channel is plotted graphically using Matlab 2016b software. Then, it has chosen 75% of 20 segmentations and also free of artifacts.
Next, the windowed signal is separated based on the frequency band. This separation used the filtering method of Finite Impulse Response (FIR) at predetermined frequencies. Determination frequencies band of EEG signal are delta (0-4Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz). The next step converted the signal in the time domain to be a frequency domain. This change used the calculation of power spectral density (PSD), which is done using the Welch method with windowing 2 seconds and overlapping 50%. The results will be obtained in the power spectrum for each segment per channel and frequency band, such as equation (2).
> @ > @ ^ `
»¼ º
«¬ ª
, max
min ,
, , , , , 5 . 5 ...
0 , ...
1 );
, ,
(cs f c q s k K K f fx fx
Pk DETG (2)
Px is power in frequency band per segment, k is a member of a set of EEG signal frequency band, and f is the upper and lower limits of each calculated brain wave. Through the selected power, peak power is detected and selected by the local maximum function. The selection was obtained peak power for each frequency band and an index that stated frequency at peak power. The QEEG results were then analyzed using statistical methods, namely the linear regression test and paired t-test.
RESULTS AND DISCUSSIONS
Initially, the QEEG parameter results of pre-therapy (baseline) of stroke patients were compared with healthy subjects. The data that obtained the mean relative power of the delta-band of stroke patients is 35.89 ± 5.305% higher than healthy subjects, which is only 14.517 ± 5.556%. For theta frequency band is closely similar, i.e., 22.66 ± 3,589%
of stroke patients and 23.01 ± 3,767% from healthy subjects. A striking difference was seen in alpha-band relative power, which showed an average of 38.44 ± 8.61% of healthy subjects. This power was more significant than stroke patients' data, which was just at 22.01 ± 4,038%. While in the beta frequency band of healthy subjects, average relative power was obtained at 24.05 ± 7.298%, and the stroke subjects group was only obtained relative power 19.45 ± 2.871%. Therefore, an indicator of success when given therapy can show a decrease in the relative power of the delta frequency band and an increase in the relative power of the alpha and beta frequency band.
The results of static bicycle and mirror combination therapy were more influential for right stroke patients than a group of left stroke patients. When given an imaginary session (motor imagery), the average delta relative power of right stroke patients dropped by -18.65 ± 4,891%,p 0.0001 and during action session by -11.23 ± 6,074%,p 0.0035 while for a mean of theta relative power, only decreased significantly during the imaginary session (motor imagery), which was -6.03 ± 6.407%,p 0.0429 . This therapy also successfully shown enhancement average alpha-band relative power during imaginary sessions (motor imagery), i.e., 5.45 ± 4.203%,p 0.0161 and during action sessions (motor execution), i.e., 6.92 ± 4,550%, p 0.0024. Furthermore, the beta frequency band's relative power also increased
dramatically during imaginary sessions (motor imagery) by 19.23 ± 9,104%,p 0.0026 and action sessions (motor execution) by 7.29 ± 7,522%,p 0.0194. The decrease results of a mean delta power relative and an increased relative power of alpha and beta frequency band from the right stroke subjects can be seen in Table 1 and Fig. 3.
TABLE 1. Relative power (%) results for linear regression and paired t-test of during to before treatment from right stroke patients
Relative
Power Task Mean Difference
with Before R2 Regression
Equation t P-value
Delta Imaginary 18.85 ± 4.362 % -18.65 ± 4.891 % 0.253 y = -0.3186x + 21.41 -9.21 0.0001 Action 26.27 ± 7.033 % -11.23 ± 6.074 % 0.042 y = -0.129x + 27.310 -4.39 0.0035 Theta Imaginary 15.35 ± 4.857 % -6.03 ± 6.407 % 0.088 y = -0.1647x + 16.68 -2.14 0.0429 Action 18.41 ± 6.122 % -2.98 ± 9.083 % 0.001 y = -0.0217x + 18.58 -0.15 0.4451 Alfa Imaginary 26.99 ± 6.159 % 5.45 ± 4.203 % 0.178 y = 0.3663x + 26.33 2.94 0.0161 Action 28.46 ± 4.434 % 6.92 ± 4.550 % 0.432 y = 0.4426x + 23.56 4.82 0.0024 Beta Imaginary 38.80 ± 8.443 % 19.23 ± 9.104 % 0.004 y = 0.0406x + 38.61 4.74 0.0026 Action 26.86 ± 6.833 % 7.29 ±7 .522 % 0.035 y = 0.0964x + 26.46 2.78 0.0194
(a) (b)
(c) (d)
FIGURE 3. Linear regression graphs of band frequencies relative power (a) delta-band, (b) theta-band, (c) alpha- band, and (d) beta-band for 15 repetitions at imaginary (motor imagery) and action/ motor execution sessions of
right stroke patient subjects..
Besides relative power parameters, there are amplitudes and time of P300 that useful in QEEG. P300 is a parameter about event-related potential (ERP) that appeared when subject responded audio stimulus around 250-750 ms [18], 250-500 [19][20][21]. After treatment for all subjects, both stroke patient and healthy, the mean result of P300 amplitude from the sensory-motor cortex area of stroke patients were higher than healthy subjects. The result can be seen in Table 2. For imaginary sessions (motor imagery), in C3 montage of subjects of stroke patients showed average amplitude by 28.55 ± 9.6 μV and action sessions (motor execution) by 27.50 ± 11.7 μV. This result was contrasted if compared with healthy subjects, which only showed an average P300 amplitude of 18.41 ± 3.1 μV for imaginary sessions (motor imagery) and 22.36 ± 3.4 μV for action sessions (motor execution). Whereas in the right hemisphere, C4 montage of stroke patients indicated P300 amplitude when given imaginary session command (motor imagery) by 25.45 ± 8.5 μV and action session (motor execution) by 21.95 ± 7.9 μV. While in imaginary sessions (motor imagery), the average P300 amplitude of healthy subjects was 16.73 ± 3.1 μV and for the action session (motor execution) was 19.18 ± 2.8 μV. Comparison of time of P300 occurrence between stroke patients and healthy subjects did not show a large difference, both of which were about ±360-390 ms.
TABLE 2. Mean of amplitude (μV) and latency (ms) P300 results of right stroke patients at C3 and C4 electrodes.
Task
Mean at C3 Electrode Mean at C4 Electrode P300 (μV) Latency (ms) P300 (μV) Latency (ms) Imaginary 28.55 ± 9.6 363.92 ± 26.6 25.45 ± 8.5 360.08 ± 20.6 Action 27.50 ± 11.7 393.07 ± 45.5 21.95 ± 7.9 387 ± 36.9
The P300 amplitude data (C3/C4 ratio) in Table 3 during the imaginary session (motor imagery) showed an increasing pattern with y 0.0056x+1.11 dan R2 0.072, but the significance test results showed.
0.3805.
, 32 . 0 p
t In contrast, action session (motor execution) indicated by then paired t-test results obtained by 0.0205.
, 59 . 2 p
t As for the time of P300 appearance (C3/C4 ratio) described if acceleration time of P300 appearance on t-count has decreased, but it was not significant. The C3/C4 ratio indicator for absolute power in the alpha frequency band showed a significantly increased result when given action session (motor execution) to right stroke patient subjects, i.e., linear regression results isy 0.0087x1.56, R2 0.023, then paired t-test results are calculated t 2.26, p 0.0324. Meanwhile, for C3/C4 ratio for the absolute power of the beta frequency band has increased significantly when given an imagery session (motor imagery), afterward linear regression results are
38 . 1 0154 .
0 x
y ,R2 0.059, with paired t-test represented t 2.74,p 0.0168.
TABLE 3. C3/C4 ratio results for linear regression and paired t-test of the last to initial repetition session of right stroke patients.
C3/C4 Ratio Task Mean R2 Regression Equation t P-value Amplitude P300 Imaginary 1.16±0.085 0.072 y = 0.0056x + 1.11 -0.32 0.3805
Action 1.35±0.318 0.205 y = ˗0.0322x + 1.60 -2.59 0.0205 Latency P300 Imaginary 1.05±0.183 0.233 y = 0.0197x + 0.90 5.59 0.0007 Action 1.15±0.162 0.001 y = ˗0.0009x + 1.14 -0.52 0.3119 Power Alfa Imaginary 1.72±0.318 0.078 y = 0.0199x + 1.55 0.54 0.3032 Action 1.64±0.261 0.023 y = 0.0087x + 1.56 2.26 0.0324 Power Beta Imaginary 1.51±0.285 0.059 y = 0.0154x + 1.38 2.74 0.0168 Action 1.45±0.307 0.132 y = 0.0249x + 1.25 1.84 0.0576 From the results of this study, when responding to an order task or command, the potential action or latency was generated by stroke patients is more significant than healthy subjects. This condition corresponds with another result
of research [17], that amplitude formed when evoked potentials occurred in healthy or ordinary people is generally formed between 0.1-20 μV within time 2-500 ms. After observed data results, the P300 amplitude of these healthy subjects showed in that range, different from stroke patient subjects whose mean amplitude was in the range of 21-30 μV. So, it can be concluded if the therapist wants a good P300 therapy result, from time to time is the P300 results must show a trend with amplitude decreasing from one session to another therapy session.
The increased results of the C3/C4 ratio for absolute power of alpha and beta frequency band reinforced initial discussion results, which stated that the average relative power of alpha frequency band at 8 EEG electrode montage evidenced a significant increase during action session (motor execution). While C3/C4 ratio indicator for the absolute power of the beta frequency band just increased when given a task for an imaginary session (motor imagery). This result showed that if the brain's left hemisphere, precisely C3 in the sensory-motor cortex, is of right stroke patient subjects, it increases compared with data in C4. This result indicated an intention of movement due to mirror activity patterns or mirror neuron therapy. These results can be input for further research related to BCI (Brain-Computer Interface)system in stroke patients, mostly right stroke patients.
ACKNOWLEDGMENTS
This research was supported by the Indonesia Endowment Fund for Education (LPDP) as a research funder. In addition, to a team of the Mandiri Center and Neuro Rehabilitation Clinic who have supported in the data recording process. Then, PT. Eracita Astamida, which lent an EEG device, and all subjects who have volunteered for this treatment.
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