Effects of trunk stabilization exercises using laser pointer visual feedback in patients with chronic stroke: A randomized controlled study

Abstract

BACKGROUND:

Many previous studies have cited the importance of trunk stabilization exercises in patients with stroke. However, the evidence for optimal trunk stabilization exercises for patients with stroke is still lacking.

OBJECTIVE:

To investigate the effects of laser pointer visual feedback in trunk stabilization exercises that are important for improving trunk dysfunction in patients with stroke.

METHODS:

In total, 30 patients with chronic stroke were randomly assigned to experimental and control groups. The experimental group underwent a traditional stroke rehabilitation program and trunk stabilization exercises using laser pointer visual feedback. The control group underwent a traditional stroke rehabilitation program and trunk stabilization exercises without visual feedback. Pre- and postintervention results after 6 weeks were evaluated using the Berg Balance Scale, static and dynamic plantar pressure, 10-m walk test, and the Korean version of the Fall Efficacy Scale. The results were analyzed using a general linear repeated measurement model.

RESULTS:

Both groups showed significant improvements in BBS scores, static plantar pressure, dynamic plantar pressure, 10 MWT, and K-FES scores after 6 weeks of intervention ( $P<$ 0.05). Compared to the control group, significant improvements were observed in the experimental group in the Berg Balance Scale scores, dynamic paretic posterior plantar pressure, 10-m walk test, and Korean version of the Fall Efficacy Scale scores ( $P<$ 0.025).

CONCLUSION:

Keywords

Stroke visual feedback stabilization exercise balance gait

1. Introduction

Stroke is one of the main causes of death and disability worldwide [1], and the demand for related rehabilitation services is increasing with the increase in the number of stroke survivors [2]. Strokes typically result in movement disorders [3] and approximately 80% stroke survivors experience movement disorders involving facial, arm, and leg movements on one side of the body [4]. In addition, impairment of trunk control commonly occurs after stroke [5], and it is one of the important predictors of functional outcomes and hospital admissions [6]. Previous studies have reported significant errors in trunk position sensation [7], poor trunk performance [8], trunk asymmetry during walking [9], delayed trunk muscle activation, and muscle weakness [10]. In patients with stroke, loss of trunk control has an important effect on the qualitative deterioration of balance and gait [11]. Therefore, they have a higher risk of falls than the average elderly [12], and their quality of life is reduced as independent daily activities become challenging [13].

Trunk stabilization is essential to ensure accurate muscle activity and movement patterns during limb movement by preventing unintentional excessive stress and maintaining a proper musculoskeletal structure [14]. Many previous studies have cited the importance of trunk stabilization exercises in patients with stroke. It was reported that trunk stabilization exercises not only improved trunk performance in patients with stroke [15, 16] but also improved balance and mobility [17]. Other studies have reported that selective trunk stabilization exercises improve walking, balance, and trunk control [18]. However, the evidence for optimal trunk stabilization exercises for patients with stroke is still lacking [19]. Therefore, it is unclear as to what type of trunk stabilization exercise is more effective in improving trunk performance of patients with stroke.

There is an increased need for research related to biofeedback training to promote motor learning in the rehabilitation process of patients with stroke [20]. In particular, these patients have higher visual dependence than normal people of the same age group and often perceive information through vision rather than body sensation [13]. Visual feedback training is a method of providing biofeedback of the movement to the subject using visual elements to notify the position or success of the performance [21]. Feedback training using external information, such as visual signals, aids in muscle coordination and voluntary contraction [22] and improves motor performance and motor learning effects [23]. In many previous studies, visual feedback training has been used to treat patients with stroke [24], and most of these studies used visual feedback delivered through mirrors, games, and virtual reality [25]. Although the effectiveness of exercises using existing visual feedback has been proven, from a motor therapy point of view, in which universality and persistence are required, there are limits to the efficient use of the equipment and economic feasibility.

We provided visual feedback using laser pointers that are commonly available devices in terms of affordability and efficiency. The novelty of this study is that it focuses on trunk stabilization exercises and determines whether a creative visual feedback method using laser pointers helps patients with stroke. If the study could demonstrate the effectiveness of trunk stabilization exercises using laser pointer visual feedback on stroke rehabilitation, this approach may present an effective treatment strategy for stroke rehabilitation. Therefore, this study aimed to investigate the effects of trunk stabilization exercise using laser pointer visual feedback in improving balance, plantar pressure, walking, and fall efficacy in patients with stroke. We hypothesized that the trunk stabilization exercises using laser pointer visual feedback applied to patients with stroke would improve balance, plantar pressure, walking, and fall efficacy compared with trunk stabilization exercises without visual feedback.

2. Materials and methods

2.1 Participants

Participants were recruited from patients with chronic stroke admitted to a rehabilitationhospital in Ulsan city from March to May 2020. The selection criteria were patients with chronic stroke who had elapsed $>$ 6 months after disease onset, patients who could walk for $>$ 10 meters independently without using aids, patients with a Korean version of Mini Mental Status Examination (K-MMSE) score of $\geqslant$ 24, and patients without visual impairments. Exclusion criteria were patients aged $>$ 80 years and those with orthopedic or neurological comorbidities that could affect motor performance, such as communication problems and walking. All participants provided consent before participating in the study. The study was approved by the Bioethics Committee of Daegu University and was conducted in accordance with the Declaration of Helsinki (1040621-202001-HR-040-02).

Figure 1.

CONSORT diagram presenting the study flow.

2.2 Study design

The study was designed as an evaluator-blind randomized controlled trial. The number of patients required for this study was calculated in advance using the G-Power 3.1 program to ensure sufficient statistical power. The sample size was based on a previous study that examined the effects of trunk stabilization exercises on improving balance and mobility [26]. Accordingly, the sample size of 26 patients was necessary to achieve an 80% probability (effect size $=$ 1.02, a $=$ 0.05, power $=$ 0.80). However, taking into account the possibility of drop-outs during the study period, 30 participants were recruited.

Participants were randomly assigned to two groups. The experimental group underwent trunk stabilization exercises using laser pointer visual feedback with a traditional rehabilitation program; the control group underwent trunk stabilization exercises without visual feedback with a traditional rehabilitation program. Assignment of the participants to the two groups was performed by physiotherapists blinded to the study using random computer-generated numbers. Figure 1 presents the study flow chart. This study was conducted and reported in accordance with the CONSORT statement on randomized trials [27, 28].

2.3 Intervention

A common program, the current stroke rehabilitation program provided by the rehabilitation hospital was applied to participants in both experimental and control groups of this study. The stroke rehabilitation program had a comprehensive approach, including neurodevelopmental therapy and trunk control, basic activities, work instruction training, functional training, and disability improvement. Both groups performed current stroke rehabilitation programs, including pelvic, leg, and reach exercises, which are commonly performed in clinical practice. Both groups underwent the traditional stroke rehabilitation program for 30 minutes a day, 5 times a week for 6 weeks.

Participants in the experimental and control groups performed an additional 30 minutes of trunk stabilization exercise a day, 3 times a week for 6 weeks. Visual feedback using a laser pointer was applied to participants in the experimental group. Wearing a hairband with a laser pointer, participants were instructed to hit a target with the laser pointer and move to a specified location, while being induced to contract the relevant muscles using visual feedback (Fig. 2). The target was installed at the end of the treatment table using a tripod stand. With the help of a therapist, this exercise was performed after the participants recognized the point where the muscle is properly contracted and maintained using a laser pointer. Participants tried to reach the point where they moved with the therapist as much as possible. The trunk stabilization exercises comprised cervical stabilization, trunk anterior flexion, trunk lateral flexion, and hip bridge exercises. The exercise intensity was gradually increased depending on the patient’s condition.

Figure 2.

Visual feedback with laser pointer and target.

For the cervical stabilization exercise, participants were instructed to press down on a towel placed under the neck while lying in a supine position with their knees bent and their chin pulled down so that the gaze directs downwards. The laser pointer moved from top to bottom and from bottom to top along the central path of the target. The starting position of the anterior flexion exercise involved bending the knees while lying in a supine position, with both arms straightened toward the knees. The head and both scapulae were lifted off the floor and held before lowering for sufficient abdominal contraction. The laser pointer moved from top to bottom and from bottom to top along the central path of the target. The starting position of the trunk lateral flexion exercise was the same as the starting position of the trunk anterior flexion exercise. The head and trunk were raised and maintained in a diagonal direction, and were subsequently lowered. The laser pointer was directed toward the midpoint of the knee in the direction the head was facing. For the hip bridge exercise, hip extension was induced by keeping the pelvis and hips lifted from the floor and then lowering them down at the starting position, in which the participants laid down with their knees bent. The laser pointer moved from top to bottom and from bottom to top along the central path of the target. Only the visual feedback using a laser pointer was excluded in the control group, and the same body stabilization exercises were performed as in the experimental group.

The treatments and interventions of the study were performed by nine physiotherapists with $\geqslant$ 5 years of experience who were not directly involved in the design and reporting of this study. Therapists received explanations and education based on the protocol and practiced the protocol for 1 month before starting the treatment for the study.

2.4 Outcome measures

Characteristics, such as age, sex, stroke onset side, and comorbidities of the participants, were collected. Participants were evaluated twice: before and after 6 weeks of intervention. The results were measured by an independent evaluator who was blinded to the group assignment of participants and was not involved in the treatment.

To assess the balancing ability of participants, the Berg Balance Scale (BBS) was used. BBS is a tool used to measure the balance of elderly people with impaired balance function by evaluating their ability to perform functional tasks. It is widely used to measure the balancing ability during movement or standing position in patients with stroke. It comprises 14 items in 3 areas and each item can be given scores ranging from 0 (minimum) to 4 (maximum). The total sum of the scores is 56 points, and better the balance, higher the score. BBS has high reliability and internal validity, with intrameasurer reliability of $r=$ 0.98 and intermeasurer reliability of $r=$ 0.97 [29].

Gaitview AFA-50 (Alfoots, Seoul, Korea) was used for static and dynamic plantar pressure measurements of participants. To measure static plantar pressure, the participants took off their shoes and stood on the platform in a comfortable position for 20 s while looking straight ahead. During this, the static bilateral plantar pressure ratio difference, static paretic plantar pressure, static paretic posterior plantar pressure, and static paretic plantar surface area were measured. To measure dynamic plantar pressure, the participants took off their shoes, stood on the platform while looking straight ahead and walked two steps at a comfortable pace. During this, the dynamic bilateral plantar pressure ratio difference, dynamic paretic plantar pressure, dynamic paretic posterior plantar pressure, and dynamic paretic plantar surface area were measured. The mean of three independent measurements was used.

The participants’ walking ability was measured via the 10-m walk test (10MWT). To give enough space for acceleration and deceleration of the walk, both ends of a straight 14-m path were marked. With the exception of the first 2 m for acceleration and the last 2 m for deceleration, the time taken to walk the middle 10 m of the path was measured [30]. 10MWT has very high reliability, with test-retest reliability of $r=$ 0.95 and intertester reliability of $r=$ 0.90 [31]. The mean of three independent measurements was used.

The Korean version of the Fall Efficacy Scale (K-FES) was used, which was translated from the previously developed Fall Efficacy Scale [32]. It comprises 13 questions and measures the degree of confidence of falling while performing daily activities described in each question. Accordingly, 0 point denotes “not afraid at all,” and 10 points denote “very afraid.” The total score ranges between 0 and 130 points, and higher the score, lower the sense of fall effectiveness, suggesting a higher risk of falling.

2.5 Statistical analysis

The data collected in this study were statistically analyzed using SPSS 18.0 for Window software (SPSS Inc., Chicago, USA) and G-Power 3.1 program [33]. All data were presented as mean $\pm$ standard deviation. The collected data were confirmed to have a normal distribution using the Shapiro-Wilk test. Accordingly, parametric tests were applied. The independent t-test or Chi-squared test was used for homogeneity testing of the experimental and control groups.

The results were analyzed using a general linear repeated measurement model. The intragroup factor was set to “time” to include the results before and after treatment, and the intergroup factor was set to “condition” to include the experimental and control groups. The probability value for “time” change indicates whether a significant change occurred between pre- and post-treatment evaluation. A significant interaction of “time $\times$ conditions” implied that there was a difference in pre- and post-treatment evaluation between the experimental and control groups. The statistical significance level (a) was set to 0.05, and when the interaction was significant, significance level (a) of the Bonferroni correction was set to 0.025.

Table 1
Characteristics of the two groups

Variable	Experimental group ( $n=$ 15)		Control group ( $n=$ 15)		$P$
Age (years)	62.53	(10.54)	60.67	(10.04)	0.624 ${}^{{\dagger}}$
Sex (Male/Female)	11/5		9/6		0.716 ${}^{{\ddagger}}$
Height (cm)	164.80	(7.28)	165.47	(7.61)	0.808 ${}^{{\dagger}}$
Weight (kg)	70.34	(8.01)	71.08	(8.44)	0.809 ${}^{{\dagger}}$
Time since stroke (month)	8.65	(2.20)	8.75	(2.44)	0.909 ${}^{{\dagger}}$
Paretic side (Left/Right)	6/9		8/7		0.481 ${}^{{\ddagger}}$
Berg Balance Scale (score)	37.27	(2.57)	38.13	(2.20)	0.330 ${}^{{\dagger}}$
Static plantar pressure
Static bilateral plantar pressure ratio (%)	9.88	(7.41)	8.94	(7.13)	0.725 ${}^{{\dagger}}$
Static paretic plantar pressure (kPa)	129.22	(14.22)	128.55	(15.26)	0.902 ${}^{{\dagger}}$
Static paretic posterior plantar pressure (kPa)	140.96	(30.51)	147.72	(32.09)	0.559 ${}^{{\dagger}}$
Static paretic plantar surface (cm ${}^{2})$	95.73	(10.58)	99.03	(14.44)	0.481 ${}^{{\dagger}}$
Dynamic plantar pressure
Dynamic bilateral plantar pressure (%)	9.13	(5.46)	9.73	(5.66)	0.769 ${}^{{\dagger}}$
Dynamic paretic plantar pressure (kPa)	147.37	(6.63)	152.14	(9.01)	0.110 ${}^{{\dagger}}$
Dynamic paretic posterior plantar pressure (kPa)	79.13	(11.44)	79.73	(12.87)	0.893 ${}^{{\dagger}}$
Dynamic paretic plantar surface (cm ${}^{2})$	118.61	(11.77)	117.53	(14.53)	0.826 ${}^{{\dagger}}$
10-m walk test (sec)	18.57	(9.07)	17.85	(5.87)	0.799 ${}^{{\dagger}}$
Korean Fall Efficacy Scale (score)	55.87	(15.49)	62.33	(33.91)	0.507 ${}^{{\dagger}}$

${}^{*}P<$ 0.05. ${}^{{\dagger}}$ Independent $t$ -test, ${}^{{\ddagger}}$ Chi-squared test.

3. Results

The general characteristics and baseline results of the experimental and control groups are presented in Table 1. A total of 30 patients, 15 patients in the experimental group and 15 patients in the control group, were included in the final analysis. In both the experimental and control groups, none of the patients were discharged or dropped out during the study. No medication-associated side effects were noted. There was no significant difference between the two groups ( $P>$ 0.05) (Table 1).

Table 2
Outcome measures in the experimental and control groups

Variable	Pretreatment				Post-treatment				$P$
	Experimental group ( $n=$ 15)		Control group ( $n=$ 15)		Experimental group ( $n=$ 15)		Control group ( $n=$ 15)		Time	Time $\times$ Condition
Berg Balance Scale (score)	37.27	(2.57)	38.13	(2.20)	42.40	(2.32)	41.13	(2.29)	$<$ 0.001 ${}^{*}$	0.012 ${}^{*}$
Static plantar pressure
Static bilateral plantar pressure ratio (%)	9.88	(7.41)	8.94	(7.13)	6.32	(5.47)	5.82	(3.79)	$<$ 0.001 ${}^{*}$	0.752
Static paretic plantar pressure (kPa)	129.22	(14.22)	128.55	(15.26)	138.47	(13.89)	136.02	(13.82)	$<$ 0.001 ${}^{*}$	0.654
Static paretic posterior plantar pressure (kPa)	140.96	(30.51)	147.72	(32.09)	155.76	(33.29)	156.13	(26.31)	$<$ 0.001 ${}^{*}$	0.236
Static paretic plantar surface (cm ${}^{2}$ )	95.73	(10.58)	99.03	(14.44)	102.78	(10.07)	104.61	(14.59)	$<$ 0.001 ${}^{*}$	0.486
Dynamic plantar pressure
Dynamic bilateral plantar pressure (%)	9.13	(5.46)	9.73	(5.66)	6.86	(5.56)	8.08	(5.81)	$<$ 0.001 ${}^{*}$	0.534
Dynamic paretic plantar pressure (kPa)	147.37	(6.63)	152.14	(9.01)	161.77	(7.75)	161.36	(12.18)	$<$ 0.001 ${}^{*}$	0.567
Dynamic paretic posterior plantar pressure (kPa)	79.13	(11.44)	79.73	(12.87)	91.07	(11.23)	84.84	(8.14)	$<$ 0.001 ${}^{*}$	0.002 ${}^{*}$
Dynamic paretic plantar surface (cm ${}^{2})$	118.61	(11.77)	117.53	(14.53)	128.38	(10.01)	127.25	(9.03)	$<$ 0.001 ${}^{*}$	0.985
10-m walk test (sec)	18.57	(9.07)	17.85	(5.87)	14.65	(6.11)	16.22	(4.77)	$<$ 0.001 ${}^{*}$	0.019 ${}^{*}$
Korean Fall Efficacy Scale (score)	55.87	(15.49)	62.33	(33.91)	44.13	(12.98)	56.60	(29.78)	$<$ 0.001 ${}^{*}$	0.021 ${}^{*}$

${}^{*}P<$ 0.05. Bonferroni correction was applied to significant interactions a significance level of 0.025.

The results before and after the intervention of the experimental and control groups are shown in Table 2. Both groups showed significant improvements in BBS scores, static plantar pressure, dynamic plantar pressure, 10 MWT, and K-FES scores after 6 weeks of intervention ( $P<$ 0.05) (Table 2). Interaction effects were observed in BBS, dynamic posterior plantar pressure, 10 MWT, and K-FES ( $P<$ 0.025) (Table 2).

Table 3

Post-hoc analysis

Variable	Power	Effect size	Mean difference (95% Cl)
Berg Balance Scale (score)	0.86	1.02	2.13	(0.53, 3.74)
Static plantar pressure
Static bilateral plantar pressure ratio (%)	0.09	0.12	0.44	( $-$ 3.29, 2.41)
Static paretic plantar pressure (kPa)	0.22	0.32	3.25	( $-$ 10.77, 4.26)
Static paretic posterior plantar pressure (kPa)	0.14	0.21	2.77	( $-$ 6.94, 12.47)
Static paretic plantar surface (cm ${}^{2})$	0.17	0.25	1.56	( $-$ 2.97, 6.09)
Dynamic plantar pressure
Dynamic bilateral plantar pressure (%)	0.16	0.23	0.61	( $-$ 2.59, 1.38)
Dynamic paretic plantar pressure (kPa)	0.40	0.52	5.57	( $-$ 2.46, 13.62)
Dynamic paretic posterior plantar pressure (kPa)	0.95	1.24	7.56	(3.03, 12.09)
Dynamic paretic plantar surface (cm ${}^{2})$	0.05	0.01	0.63	( $-$ 6.74, 6.86)
10-m walk test (sec)	0.73	0.84	2.29	( $-$ 4.34, $-$ 0.23)
Korean Fall Efficacy Scale (score)	0.72	0.83	6.00	( $-$ 11.39, $-$ 0.61)

CI, confidence interval. Effect size represents intragroup differences in pre–post intervention differences.

The postanalysis results are shown in Table 3. BBS scores, dynamic posterior plantar pressure, 10MWT, and K-FES scores showed interactive effects as well as large effect size and power (Table 3).

4. Discussion

The purpose of this study was to investigate the effects of laser pointer visual feedback on trunk stabilization exercises to improve balance, plantar pressure, walking, and fall efficacy in patients with stroke. Studies have shown that trunk stabilization exercises using laser pointer visual feedback improve balance, walking ability, and fall efficacy in patients with stroke more efficiently than trunk stabilization exercises without visual feedback. These results provide evidence that visual feedback using laser pointers has a positive effect on trunk stabilization in patients with stroke.

Balance and gait abilities in both groups were improved by trunk stabilization exercises with or without visual feedback. Intergroup comparison revealed greater improvement in trunk stabilization exercises using laser pointer visual feedback. Balance is the biggest factor that affects the functioning of patients with stroke [34]. Patients with stroke have impaired balancing ability due to damage to their trunk muscles [35]. In a previous study comparing the effects of traditional physiotherapy and additional trunk-stabilizing exercises, additional trunk-stabilizing exercises had a positive long-term effect on improving balance in patients with subacute stroke [17]. In addition, a study examining the effects of selective trunk muscle exercises reported clinical improvement of balance in patients with acute stroke [18]. The improvement of walking ability demonstrated by 10MWT was confirmed in our study. The gait of patients with stroke is an important factor in understanding daily life movements and quality of life [36], and is an important measure in motor function and recovery [37]. A previous study that examined the effects of trunk stabilization exercises on ab thickness, balance, and gait in patients with stroke reported significant improvements in ab contraction, balance, and walking ability after 6 weeks of intervention [14]. In addition, a recent systematic review found that trunk training improves trunk control, balance, and mobility in patients with stroke [38]. This study also demonstrated similar results. It is believed that trunk stabilization exercises applied together with traditional stroke rehabilitation programs improved balance and walking ability, by improving the trunk performance of the participants in both experimental and control groups. A number of recent studies have reported positive effects of various trunk stabilization exercises applied to stroke patients. It was found that the three-dimensional active trunk training exercise applied to stroke patients was more effective in improving trunk control ability, trunk strength, and balance ability than general trunk training [39]. Dynamic neuromuscular stabilization was found to be more effective in activation and thickness of deep core muscles than neurodevelopmental treatment [40]. In addition, it was reported that robot-assisted trunk control training was beneficial and effective in improving trunk postural control and balance ability in stroke patients [41]. Therefore, research is needed to add applicable visual feedback such as laser point for more effective and efficient trunk stabilization exercise.

Trunk stabilization exercises using laser pointer visual feedback in the experimental group improved balance and walking ability better than trunk stabilization exercises without visual feedback in the control group. A previous study showed that performing accurate exercises in real-time with visual, auditory, and tactile feedback can increase the therapeutic effects [42]. To improve balance and walking ability, training using visual feedback is being applied to treatment in clinical settings [43]. In addition, it is reported that the concentration and activation of the cerebral cortex is increased when there is a visual target than when there is no visual target [44]. It is believed that the trunk stabilization exercise method using laser pointers and a target used in this study promotes motor development to restore motor function and improve brain plasticity. This result is consistent with that of a previous study that reported that the rehabilitation method using visual feedback promotes motor learning in patients with stroke [45]. Many studies have reported the effect of various visual feedbacks on the rehabilitation of stroke patients. A study on sit-to-stand training combined with real-time visual feedback reported that visual feedback was more effective for lower extremity strength, balance, and gait [46]. In a study on trunk control training using smartphone visual feedback, visual feedback improved balance and trunk performance [47]. In addition, it was reported that afferent electrical stimulation applied with mirror visual feedback effectively improved muscle strength, balance, and walking ability [48]. There is no study comparing the laser point used in this study with other types of visual feedback, so additional research on this will be needed.

Falls not only increase the risk of secondary damage but also decrease the sense of efficacy needed for self-activity and increase the risk of reduced mobility and physical function by limiting the area of physical activity [49]. Patients with stroke are at a higher risk of falls than healthy individuals of similar age and sex [50]; they experience falling in hospitals (14%–65%) [51] or within the first 6 months after discharge (37%–73%) [52]. Therefore, many previous studies have reported improvements in falls using various intervention methods, such as dual-task exercises [53], cognitive exercises [54], and backward walking training [55]. Factors that could affect falls in patients with stroke include balancing ability [56], walking speed [57], and trunk control ability [15]. In this study, trunk stabilization exercises improved the fall efficacy of both the experimental and control groups, and the effect was particularly greater in the experimental group compared to the control group. Furthermore, the results revealed improved balancing and walking abilities in both groups, with the experimental group showing greater improvement. As a result, trunk stabilization exercises can improve fall efficacy by improving balancing and walking abilities of patients with stroke. Further, the method using visual feedback proved to be more effective. This finding is clinically significant because, to best of our knowledge, there has been no study on the impact of trunk stabilization exercises using visual feedback on fall efficacy in patients with stroke.

Plantar pressure is used as an indicator to determine the qualitative state of gait and balance [58]. In addition, plantar pressure measurement is a highly reliable test that directly discerns the weight support characteristics of the soles of the feet [59]. Patients with stroke have more weight support in the nonparetic lower extremities [60]. Another feature is that as the feedback ability through the paralyzed sole is reduced, the plantar pressure moves to the front of the foot and toe areas and the ratio of the heel pressure distribution is lowered [61]. Participants in this study also showed such characteristics in plantar pressure. The trunk stabilization exercises in this study improved static and dynamic plantar pressure in both the experimental and control groups. These results indicate that the trunk stabilization exercises evenly distribute the pressure center by improving trunk performance. However, the effects of laser pointer visual feedback were observed only on dynamic paretic posterior pressure. Patients with stroke develop ankle joint deformation that can affect plantar pressure. The weakening of the dorsiflexion muscle and the stiffness of the plantar flexion muscle induces plantar flexion and deformation in the ankle [62]. As the study focused on the effects of trunk stabilization exercises and sought to determine the effects of visual feedback, ankle deformation in patients with stroke was not within the scope of the study. Further, as the method of our study focused only on improving trunk performance, it is considered that there was no significant difference between the two groups in plantar pressure, which can affect the condition of the ankle joint.

The limitation of this study is that the number of subjects is too small to generalize the results, and the long-term effects of trunk-stabilizing exercises with visual feedback remain unclear due to the lack of follow-up. The Fall Efficacy Scale alone is insufficient in analyzing psychological factors, which are important fall factors in patients with stroke. It is thought that the visual feedback using the laser pointer used to induce the correct contraction of the trunk muscles may have been accompanied by indirect eye movement through the laser pointer stare. It is assumed that the vestibular eye reflex through eye movement may have affected the improvement of balancing ability to some extent, which was not properly controlled in this study. We believe that various follow-up studies that can complement this study should be conducted with a systematic and long-term perspective.

5. Conclusion

Our results demonstrated the effectiveness of visual feedback during trunk stabilization exercises for resolving trunk dysfunction in patients with stroke. Trunk stabilization exercises using laser pointer visual feedback have been found to be effective in balance, walking, and fall efficacy in patients with stroke. Because the visual feedback method using laser pointers is easily available in terms of affordability and efficiency, our findings may be particularly helpful in clinical settings.

Footnotes

Conflict of interest

None to report.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

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Effects of trunk stabilization exercises using laser pointer visual feedback in patients with chronic stroke: A randomized controlled study

Abstract

BACKGROUND:

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSION:

Keywords

1. Introduction

2. Materials and methods

2.1 Participants

2.3 Intervention

2.5 Statistical analysis

Table 1 Characteristics of the two groups

Table 2 Outcome measures in the experimental and control groups

5. Conclusion

Footnotes

Conflict of interest

Funding

References

Table 1
Characteristics of the two groups

Table 2
Outcome measures in the experimental and control groups