Gait Characteristics in Stroke Patients with Vestibular Symptoms Under Different Walking Speed Conditions

doi:10.21203/rs.3.rs-4831046/v1

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Gait Characteristics in Stroke Patients with Vestibular Symptoms Under Different Walking Speed Conditions

https://doi.org/10.21203/rs.3.rs-4831046/v1

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Objective

To investigate the gait kinematic parameters of stroke patients with vestibular symptoms at different walking speeds.

Methods

Thirty-eight patients with brainstem stroke hospitalized in Tianjin Huanhu Hospital from June 2022 to June 2023 were included, along with 30 control subjects matched in gender, age, and education level. The walking stability was evaluated by 7⁃Meter walking test, and the differences in gait parameters were analyzed under conditions of fast, self-selected, and slow walking speeds.

Results

Under the fast-walking conditions, there were no statistically significant differences in the spatial gait parameters of step speed and stride length between the two groups (P > 0.05). However, there was a statistically significant difference in the percentage of double support time, a temporal parameter (P < 0.05). No significant differences were found in the percentage of terminal double support, stride frequency, and stride duration (P > 0.05). Under the self-selected and slow walking conditions, except for stride frequency and step duration, all other gait parameters showed statistically significant differences between the two groups (all P < 0.05). Specifically, in the group with vestibular symptoms, their spatial gait parameters of stride length and step speed were lower than those in the control group (both P = 0.000), while the percentage of terminal double support and double support time were higher than the control group (P < 0.01).

Conclusion

Walking speed significantly influences the gait parameters of stroke patients with vestibular symptoms, particularly under slow and self-selected walking speeds. This provides important clinical value for the implementation of precision rehabilitation treatment.

Biological sciences/Neuroscience

Health sciences/Health care

Health sciences/Neurology

Stroke

Vestibular

Walking

Postural Balance

Rehabilitation

Studies have shown that motor function in stroke patients with hemiplegia is significantly impaired, leading to slow walking speed, gait asymmetry, and a higher risk of falls. This negatively impacts the overall functional recovery or independent walking of patients [1–2]. Clinical manifestations of the stroke patients with vestibular symptoms include vertigo/dizziness, blurred vision, and unstable posture and gait. These symptoms are common in strokes affecting the brainstem or cerebellum, which are supplied by the posterior circulation [3]. These patients often exhibit an overconfidence in their balance ability when in a lying position due to the absence of noticeable limb paralysis. However, standing and walking require higher postural stability control and greater reliance on the vestibular system. Therefore, these patients are more prone to losing postural stability and have a higher risk of falling [3–4]. Walking speed is closely related to the improvement of quality of life, making the enhancement of walking speed a crucial goal in stroke rehabilitation.

In daily life, adjusting gait speed (i.e., increasing and decreasing walking speed) and gait initiation/termination are considered as important functional tasks. For example, when walking is combined with talking or other attention-demanding activities, walking speed tends to slow down. Similarly, when attempting to change direction while walking, such as making a turn, walking speed decreases compared to straight-line walking. Additionally, walking speed reduces when approaching a stationary object or when a moving object approaches an individual. Therefore, reducing walking speed to below a comfortable walking pace is considered a relatively more complex task. Studies have demonstrated that compared to comfortable walking speed, slow walking might involve different motor and postural control mechanisms[5–6]. At very slow walking speed, the body shifts from motor control to postural muscle control. Faster movement speeds might be associated with greater vestibular-driven inhibition, hence the reduction in walking speed could be related to decreased vestibular-driven inhibition[7–9].

This study analyzes the kinematic parameters of gait in patients with brainstem infarction and vestibular symptoms under different speed conditions to explore the role of the central vestibular system in gait changes. Future rehabilitation treatments can target the gait characteristics of patients walking at different speeds to improve treatment effectiveness, thereby enhancing balance and gait function in stroke patients with vestibular symptoms.

Participants

A total of 38 unilateral brainstem infarction patients were selected from June 2022 to June 2023. Inclusion Criteria: (1) Patients meeting the diagnostic criteria for stroke, confirmed as cerebral infarction by head MRI, and experiencing their first stroke. (2) Patients meeting the diagnostic criteria for vestibular symptoms as defined by the International Classification of Vestibular Disorders[10]. (3) Patients aged between 30 and 60 years. (4) Disease duration of 5 to 14 days. (5) A score of ≥ 3 on the Functional Ambulation Category (FAC) scale. Patients able to walk independently for 10 meters without assistance and maintain this for 15 minutes. Exclusion Criteria:(1) Patients with multiple lesion strokes confirmed by imaging (head MRA, CTA, or DSA), or those with stroke in the internal carotid artery system supply area, severe stenosis of large vessels, or arterial dissection. (2) Patients with reduced peripheral vestibular function or hearing loss. (3) Patients with proprioceptive abnormalities or severe comorbid visceral or orthopedic diseases. (4) Patients with tumors, cerebrovascular malformations, or high signal white matter lesions (Fazekas score > 1)[11]. (5) Patients unable to complete the test due to cognitive impairments, unilateral neglect, or aphasia. Informed consent was obtained from all subjects and/or their legal guardian(s). The study has been approved by Ethics Committee of Tianjin Huanhu Hospital (approval No.: 2021-020) and registered for clinical trial (date of first trial registration: 24/03/2021; registration number: ChiCTR2100044556). All methods were performed in accordance with the relevant guidelines and regulations.

Study design

Patients were asked to walk back and forth naturally at a comfortable speed on a 7-meter walkway. A metronome was used to set tasks for walking at different speeds, with patients walking in sync with the metronome rhythm. The metronome frequencies were set to 140 beats per minute for fast walking and 70 beats per minute for slow walking. Gait parameters were collected at three different walking speeds. Each task was performed three times with a one-minute rest in between.

Assessments

Gait analysis was conducted using OPAL wearable sensors and Mobility Lab software from APDM, USA. A total of six wearable sensors (containing gyroscopes and accelerometers) were worn by the subjects on the second sternal handle, the fourth-fifth lumbar vertebrae, both wrists, and both feet. Gait parameters recorded included walking amplitude, walking speed, walking frequency, stride time, proportion of double support phase, and proportion of terminal double support phase.

Statistics

All data processing and analysis were performed using SPSS 23.0 statistical software. Count data were expressed as relative composition ratios (%) or rates (%), using the χ2 test for comparison. Normality tests were conducted using the Shapiro-Wilk test. Non-normally distributed data were expressed as median and interquartile range [M (P25, P75)], and comparisons between groups were made using the Mann-Whitney U test.

Normally distributed or approximately normally distributed data were expressed as mean ± standard deviation (x ± s). Data comparisons between two groups were performed using independent samples t-test. A P-value < 0.05 was considered statistically significant.

The comparison of sex, hypertension, coronary heart disease, diabetes, hyperlipidemia, smoking, and drinking was performed using the χ2 test. The comparison of education level was performed using the Mann-Whitney U test, while the comparison of age and BMI was performed using the two-independent-sample t-test. NIHSS stands for the National Institutes of Health Stroke Scale, and BMI stands for body mass index.

Data availability

All data generated or analysed during this study are included in this published article.

38 patients with brainstem stroke hospitalized were recruited, including 26 males and 12 females. Disease duration ranged from 6 to 14 days, with an average of 9.5 (8, 11) days. Age range was 40 to 60 years, with an average age of 49.37 ± 8.92 years. Education level ranged from 6 to 15 years, with an average of 12 (9, 12.75) years. Among them, 20 patients had hypertension (52.63%), 15 had coronary artery disease (39.47%), 15 had diabetes (39.47%), 18 had hyperlipidemia (47.37%), 15 were smokers (39.47%), and 6 were drinkers (15.79%). NIHSS scores ranged from 1 to 2, with an average score of 2 (1, 2).

30 healthy individuals with normal vestibular function and no history of diseases affecting walking function were selected as the control group, including 14 males and 16 females. Age range was 46 to 60 years, with an average age of 52.69 ± 3.93 years. Education level ranged from 6 to 15 years, with an average of 12 (9, 12) years. Among them, 15 had hypertension (50%), 10 had coronary artery disease (33.33%), 12 had diabetes (40%), 13 had hyperlipidemia (43.33%), 10 were smokers (33.33%), and 4 were drinkers (13.33%). There were no statistically significant differences in general demographic data between the two groups (all P > 0.05, Table 1), indicating balanced and comparable groups.

Table 1

Demographics of control and stroke with vestibular symptoms groups
Characteristic	Control group (n = 30)	Stroke with vestibular symptoms group (n = 38)	P
Gender, n (%)			0.07
Male	14(46.67)	26(68.42)
Female	16(53.33)	12(31.58)
Age (y), x ± s	49.37 ± 8.92	49.37 ± 8.92	0.604
BMI (kg/m²), x ± s	25.22 ± 3.08	26.93 ± 4.8	0.06
Course of disease (days), (x ± s)	/	9.5(8,11)
Education (y), [M (P25, P75)]	12(9,12)	12(9,12.75)	0.367
With hypertension, n (%)	15(50)	20(52.63)	0.829
With coronary heart disease, n (%)	10(33.33)	15(39.47)	0.602
With diabetes, n (%)	12(40)	15(39.47)	0.965
With hyperlipidemia, n (%)	13(43.33)	18(47.37)	0.74
History of smoking, n (%)	10(33.33)	15(39.47)	0.602
Alcohol use, n (%)	4(13.33)	6(15.79)	0.776
NIHSS score at admission, x ± s	/	2(1,2)

Gait test showed that under fast walking conditions, the differences in spatial gait parameters (walking speed and stride length) between the two groups were not statistically significant. Only the difference in the proportion of double support phase among the gait parameters was statistically significant (P < 0.05). The differences in the proportion of terminal double support phase, walking frequency, and stride time were not statistically significant (P ≥ 0.05, Fig. 1).

Under slow walking conditions, there were no differences in walking frequency and stride time between the healthy control group and the stroke group with vestibular symptoms (P ≥ 0.05). In the stroke group with vestibular symptoms, the spatial parameters of walking speed and stride length were significantly lower than those of the healthy control group (P < 0.05). The proportions of terminal double support phase and double support phase were significantly longer compared to the healthy control group (P < 0.05, Fig. 2).

Under normal walking conditions, the differences in gait parameters other than walking frequency and stride time between the two groups were statistically significant (all P < 0.05). The spatial gait parameters of stride length and walking speed in stroke patients with vestibular symptoms were significantly lower than those in the healthy control group (both P = 0.000). Additionally, the proportions of terminal double support phase and double support phase were significantly higher in the stroke group with vestibular symptoms (P < 0.01, Fig. 3).

Dizziness and vertigo are common symptoms in patients visiting neurology clinics and emergency departments, with its incidence increasing with age. Stroke is the most common cause of central dizziness/vertigo, accounting for 3%-5% of acute dizziness/vertigo cases[12]. Unlike peripheral dizziness/vertigo, central dizziness/vertigo is prone to misdiagnosis and carries a higher risk of mortality and poorer prognosis. Damage to central vestibular (such as the vestibular nuclei, cerebellar flocculus, cerebellar nodulus, vestibular thalamus, and insula) or vestibular-related pathways (vestibulo-cortical, vestibulo-spinal, and vestibulo-cerebellar pathways) can lead to vestibular-related symptoms such as dizziness/vertigo, diplopia, oscillopsia, and balance and gait abnormalities, accounting for approximately 30%-60% of posterior circulation strokes[12–13]. Clinically, these patients may not exhibit obvious limb paralysis, but even after dizziness/vertigo symptoms improve, they may still be unable to stand and walk normally, displaying head and eye posture deviations, unstable gait, spatial orientation disorders, and a high risk of falls[4]. This study aims to explore the differences in spatiotemporal gait parameters in stroke patients with vestibular symptoms under different walking speeds, to identify their movement patterns and provide more precise rehabilitation strategies.

The vestibular system perceives body position and external stimuli through peripheral receptors, transmitting vestibular signals to the vestibular centers, and adjusting head and eye movements and body posture to achieve clear and stable vision, postural stability, and accurate spatial orientation[14]. The damaged central vestibular structures in the brainstem, including the dorsal medulla, pontine tegmentum, and midbrain tectum, lead to abnormal utilization and integration of vestibular information in the central nervous system, resulting in dizziness/vertigo, blurred vision, postural instability, and gait abnormalities[12–13]. Walking is a primary form of movement in daily life, and gait is a behavioral characteristic of human walking, serving as an important indicator of motor recovery in stroke patients. Gait analysis objectively describes walking patterns using gait analysis equipment to analyze biomechanical and kinematic features by capturing precise walking characteristics, facilitating more accurate assessments and personalized rehabilitation. Hemiplegic patients typically exhibit gait characteristics such as reduced walking speed, shortened stride length and frequency, increased step width, and altered stance and swing phases. To maintain postural stability, hemiplegic patients often reduce the time spent on the affected limb during the stance phase and prolong the swing phase[15–16]. Studies have shown that bilateral vestibular patients display increased gait variability, shortened stride length and width, prolonged double support phase during walking, and increased trunk sway angle[17]. Our previous study indicated that stroke patients with vestibular symptoms in the posterior circulation exhibit reduced walking speed, shortened stride length and frequency, prolonged double support phase, and increased trunk sway angles in the sagittal and coronal planes compared to normal controls [4]. Thus, stroke patients with vestibular symptoms exhibit a different gait pattern from typical hemiplegic patients.

Vestibular control of balance during walking shows stage-dependent regulation, depending on when the lower limbs contact the ground and the role of muscles in balance control. Specifically, the response of lower limb muscles to vestibular stimulation primarily occurs during the stance phase of the same limb[18–20]. Study confirmed that the medial gastrocnemius muscle, as the primary power source for the foot during normal walking, is sensitive to vestibular input in the late stance phase. The gluteus medius muscle contributes to foot placement strategies, with its activity related to the foot placement of next step and being sensitive to vestibular errors before heel strike[21]. Coherence studies between electromyography (EMG) signals and vestibular electrical stimulation also found that the peak coherence between vestibular electrical stimulation and EMG appears during the double support phase of the gait cycle[21–22]. Therefore, all muscles involved in balance control during movement are coupled with vestibular stimulation at specific periods of the gait cycle, but the maximum net response to vestibular stimulation occurs during the stance phase. Piccolo et al. found that active stepping and accurate foot placement during the terminal double support phase of the gait cycle requires the vestibular system. The brain needs to integrate, and process received vestibular information during the terminal double support phase to determine whether the body has undergone the correct displacement, ensuring a stable walking posture[23]. Therefore, the vestibular system plays a crucial role during the stance phase of the gait cycle. The patient's double support phase increases when vestibular information is impaired.

This study found that, compared to the control, stroke patients with vestibular symptoms had an extended proportion of double support phase under fast walking conditions, while other gait parameters:walking speed, stride length, terminal double support phase, and stride time showed no significant differences. Under slow and normal walking conditions, stroke patients with vestibular symptoms exhibited slower self-selected walking speeds, shorter stride lengths, and longer double support phases, consistent with our previous findings. These results suggest that stroke patients with vestibular symptoms achieve a gait pattern similar to the control group under fast walking conditions by extending the double support phase. However, under normal and slow walking conditions, they enhance walking stability by extending the double support phase, reducing walking speed, and shortening stride length.

Vestibular control of balance during movement decreases with increasing movement speed (from posture to walking to running). The central nervous system inhibits vestibular signals in a speed-dependent manner, supporting spinal mechanisms expressed through muscle synergy to control movement behavior[19, 22]. Research confirms that fast movement behavior is a highly automated process based on spinal locomotor generators, controlled by supraspinal structures that inhibit unstable vestibular inputs. This vestibular inhibition prevents irregular head movements from interfering with the activities of spinal and supraspinal networks controlling fast movement behavior. Compared to fast movement behavior, posture and slow walking rely more on vestibular inputs[24]. Brandt et al. found that patients with unilateral vestibular neuritis tend to deviate to the affected side when walking with their eyes closed, but do not deviate when running[7, 25]. Jahn et al. found that vestibular-evoked compensatory whole-body sway responses during running were reduced compared to walking[26]. Dakin et al. showed that vestibular-muscle coupling reduces with increased walking speed especially during the stance phase of the gait cycle, but appears unaffected during the swing phase[19]. Therefore, vestibular input is differentially regulated based on the walking speed and pattern used. For hemiplegic stroke patients, a common strategy to avoid imbalance and falls is to reduce speed to enhance postural stability. However, studies on the gait of sensory-impaired patients found that these patients (with visual, proprioceptive, and vestibular impairments) typically show greater spatiotemporal gait variability under slow walking conditions and relatively less variability under fast walking conditions. This is because balance and postural regulation during fast walking depend less on sensory system feedback control[27–29]. Thus, postural control of gait during slow walking primarily relies on sensory system feedback. The above studies explain why stroke patients with vestibular symptoms achieve a gait pattern similar to the control group under fast walking conditions, as vestibular input is suppressed, therefore masking the impairment of vestibular information. However, under slow and normal walking conditions, more vestibular feedback is required, and the impaired vestibular information in patients cannot meet walking demands. Consequently, patients extend the support phase time and slow down to increase stability and prevent falls.

Study limitations

This study has several limitations: (1) The sample size is small and not continuously enrolled, possibly introducing selection bias; (2) This study only analyzed temporal and spatial parameters, while kinematic parameters (joint angles, pelvic movement), kinetic parameters (ground reaction forces, moments), and EMG parameters could also provide further information to help analyze patients' gait characteristics; (3) The severity of vestibular function impairment in patients was not graded in detail. Future studies will expand the sample size, include multicenter studies, analyze more comprehensive gait parameters, objectively evaluate vestibular function impairment severity, and explore the correlation between vestibular function and gait parameters to provide objective theoretical support for precise rehabilitation treatment.

In summary, stroke patients with vestibular symptoms exhibit significant differences in gait parameters under normal and slow walking conditions compared to fast walking conditions. Clinically, it is essential not only to conduct fast walking training for such stroke patients but also to focus on postural and gait training under normal and slow conditions. This provides a new perspective for stroke rehabilitation, helping patients back to normal life and work.

BMI

body mass index

EMG

electromyography

FAC

Functional Ambulation Category scale

NIHSS

National Institutes of Health Stroke Scale.

Author Contribution

Author Contributions: M. Y. proposed and designed the study, performed the experiments, collected and analyzed the data, wrote and revised of the manuscript; Y. L., L. C., F. W. and J. C. were responsible for the implementation and evaluation of the experiments, and data collection; Y. Z. was responsible for the quality control and review of the article, overseeing the overall supervision and management of the manuscript. All authors confirmed the final version of the paper.

Acknowledgments

This study was supported by Tianjin Health Research Project (Grant No. TJWJ2024MS029), Tianjin Science and Technology Project (No. 21JCYBJC00420), and Tianjin Medical Key Discipline (Specialty) Construction Project (No. TJYXZDXK-052B).

Conflicts of interest:

None declared.

Data Availability

All data generated or analysed during this study are included in this published article

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No competing interests reported.

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Version 1

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You are reading this latest preprint version

Gait Characteristics in Stroke Patients with Vestibular Symptoms Under Different Walking Speed Conditions

Status:

Version 1

Abstract

Objective

Methods

Results

Conclusion

Figures

Introduction

Materials and methods

Participants

Study design

Assessments

Statistics

Data availability

Results

Discussion

Study limitations

Conclusions

Abbreviations

Declarations

Author Contribution

Acknowledgments

Data Availability

References

Additional Declarations

Status:

Version 1