European Journal of Cardiovascular Medicine

A stroke is characterized as paralysis or weakness of one side of the body, including the upper limb, lower limb, and trunk. Individuals with stroke present with altered muscle tone, abnormal synergy patterns, visual changes, altered coordination, and minimization in postural control and balance [1, 2].

The trunk provides background stability during mobility. It provides stability to aid through the core muscles for postural control and activities of breathing,  speech, balance, upper limb, and lower limb functions, along with the ability to do ADLs and ambulation.[3]  Trunk muscles play a vital role in supporting the human body in antigravity postures as well, such as sitting and standing, and also help in the stabilization of proximal body parts during voluntary limb movements.[4] In contrast, hemiplegic subjects show limited trunk movement concerning the gravity following trunk weakness. Hence the upper and lower limbs go into a spastic synergic pattern [5]. Good trunk stability is essential for maintaining balance as well as extremity use during daily functional activities.) [6] Poor recovery of trunk muscles, which results in severe disability and also a reduction in the activities of daily living (ADL), leads to postural instability and disequilibrium thus affecting gait & functional independence. [7]

Perturbation is a disturbance of motion or a change in the static state of equilibrium. [8] Manual perturbation is a treatment approach that works through external postural perturbation, internal postural perturbation, and perturbation through some voluntary tasks. External perturbation includes ‘lean and release' perturbations where participants lean forward, backward, left, or right on the physiotherapist's hands and are released suddenly (during stable tasks); a push or pull from the physiotherapist; or a trip with the physiotherapist's foot (during mobile tasks).  (Manual perturbation training is vital in restoring reactive balance and improving functions and mobility. [9]

Internal perturbations occur while the patient is performing an anticipated activity and is not controlling their center of mass adequately. It’s the patient’s lack of control of movement, poor coordination, lack of center of mass awareness, and lack of adequate motor response that leads to the center of mass approaching or falling outside of their base of support. [10]  

Perturbation through voluntary tasks is an exercise aimed at improving the control of fall-prevention reactions when one loses balance. Perturbation through voluntary tasks involves whole-body movements, and these movements have similar benefits to other exercises, such as walking, and may, over time, also improve strength and conditioning. [10]

Perturbation through voluntary tasks can potentially improve multiple aspects of physical health simultaneously. Each task can be modified to increase or reduce the difficulty, depending on the participant’s abilities. [11] [12]

Proprioceptive neuromuscular facilitation (PNF) is an approach to enhancing motor learning to improve motor function and facilitate maximal muscular contraction. In PNF, patterns of diagonal and rotational exercises in nature are used to improve ADL functions and mobility.  Techniques such as rhythmic initiation, slow reversal, and agonistic reversal are used; PNF is one of the well-established treatment techniques incorporating functional diagonal movement patterns in the rehabilitation of subjects with stroke. [13] PNF techniques focus on the stimulation and facilitation of proprioceptors to increase demand on the neuromuscular mechanism to obtain and simplify their responses. [14] [15]

The Conventional physiotherapy rehabilitation plan, essentially conventional physical therapy based on ADL skills, included:

Passive range of motion exercises, stretching, Active assistive exercises, Active exercises, Resistive exercises, Exercises in different functional positions, Weight-bearing exercises, Weight shifting exercises, and reaching exercises in sitting, kneeling, and standing.

Bridging: simple bridging and progressed to one leg bridging and bridging with Vestibular ball, Truncal exercises, forward and backward lean with assistance, Upper and lower trunk rotation, Flexion of the trunk on the vestibular ball, Flexion, and extension of the trunk in sitting and standing.

Gait training:  Gait training was done with the parallel bar as well as without the parallel bar and mirror for the feedback [16] [17] [18] [19].

Inclusion and Exclusion Criteria

Sample Size: 30 subjects, 15 subjects in each group, wherein

Group A: 15 (Manual Perturbation Training and Conventional Therapy) and

Group B: 15 (Proprioceptive Neuromuscular Facilitation and Conventional therapy).

Materials used

Outcome Measures:  MMSE, Trunk Impairment Scale, TUG, Dynamic Gait Index, Gait Parameters. Data collection sheet, Inch tape, Consent form, Marker, Stationeries, Obstacles of the same size: boxes, cones, Armchair, Stopwatch, Assessment form, Chart papers, Colour (laundry blue), Mattresses, and Foam.

Variables

Independent Variables,

PNF exercises

Manual perturbation exercises and

Dependent Variables,

Trunk control

Balance

Mobility and

Gait parameters

Figure.1 patient performing walking around the obstacles a component in DGI

The treatment procedures are as follows:

Manual Perturbation Training [9, 25, 26]

1) External perturbation

• Push/ Pull from the therapist
• Forward/Backward/Sideways
• Shoulder/Trunk/Pelvis
• Positions: Sitting/ Quadruped/ Kneeling/ Standing
• 10 perturbations, 3 sets each for 5 weeks
• Progression was done using the mattress in the last 3 weeks

2) Internal perturbation

Position: Sitting/ Quadruped/ Kneeling/ Standing

• Activities:
• Reaching (touching the ball held at a distance)
• Bending forward and touching the ground in sitting, kneeling for 5 weeks
• Standing in the last 3 weeks.
• Turning to look backward in all positions.

Proprioceptive neuromuscular facilitation: - [13, 14, 15, 20, 21]

1) Diagonal patterns – Trunk

• Lifting- reversal lifting
• Chopping- reversal chopping
• Position: Supine/ Sitting (first 5 weeks)
• Kneeling/Standing (last 3 weeks)

Pelvic pattern

• Anterior elevation
• Anterior depression
• Posterior elevation
• Posterior depression

Position: side-lying

Lower extremity - Position: Supine/ Sitting – Techniques- D1/ D2 Flexion and D1/D2 Extension

1) Rhythmic initiation

Passively done for 2 weeks

Active assisted for the next 2 weeks

Active for 1 week

Active resisted in the last 3 weeks

Trunk: Flexion/ Extension -Position: Sitting

Pelvis: Anterior Elevation/ Anterior Depression/ Posterior Elevation/ Posterior Depression - Position: Side-lying

Lower extremity: D1 Flexion/Extension, D2 Flexion/Extension- Position: Supine/ Sitting

2) Slow Reversal -Trunk:

• Positions: Side-lying for 5 weeks and prone position with elbow supported for last 3 weeks
  • Pushing diagonally forward and backward against resistance provided by the therapist.
• Pelvic: Anterior Elevation/ Anterior Depression/ Posterior Elevation/ Posterior Depression
• Position: Side-lying-
• Lower extremity: Leg up and foot Dorsi Flexion/ Leg down and Plantar Flexion, Ankle Dorsi Flexion and Plantar Flexion
• Positions: Side-lying for 5 weeks & Supine for last 3 weeks

3) Rhythmic stabilization -It was done in the last 3 weeks- Trunk: Forward and Backward movement

• Position: Sitting
• Pelvis: Forward/ Backward
• Positions: Side-lying/ Quadruped/ Kneeling
• Lower extremity: Leg up and Dorsi Flexion/ Leg down and Plantar Flexion
• Position: Supine

Conventional PT

These exercises prevent complications of immobilization and improve Activity of Daily Living (ADL) skill at the earliest. This helps in preventing contractures and development of abnormal postures. These exercises start with simple movements and subsequently, complex movements and actions are tried. The subject's functional abilities, or abilities to perform different movements or tasks (e.g., pattern movements, selective movements, standing up, maintaining standing, walking) were the basis for treatment. The same therapist worked with an individual subject throughout the program of conventional treatment. [27, 28, 29]

Data Analysis

Statistical analysis was carried out using SPSS Version 22.

Level of significant difference was set a priori at p≤ 0.05 level, Mean and SD were calculated for the continuous variables and values are reported as mean ± standard deviation.

Levene’s test was used for the baseline comparison of the data.

Between groups, a comparison was made using unpaired t-test and within- group comparison was made using the paired student t-test, both pre-intervention and post-intervention statistics of outcome measures are presented.

Flow Chart

Results

Demographic characteristics of the study participants

A total of 30 patients were recruited for this study. There were 8 females and 22 males aged 50 to 70 years (mean age- 53.3). Males were more affected than females. The primary etiology for stroke consisted of hypertension (N= 21), diabetes (N=7), and hypothyroidism (N=2) as a potential risk factor and not a direct cause of stroke. Among the total sample, 87% were ischemic stroke & 13 % were haemorrhagic strokes. The sample size was based on the number of patients who met the inclusion or exclusion criteria.

The participants' demographic characteristics are summarized in the table below.

Table: - 1. Demographic distribution of the study population

Table 2. Baseline (Pre-Intervention) Comparison of Both Groups

*Abbreviation: TIS: Trunk Impairment scale TUG: Timed Up and Go test DGI: Dynamic Gait Index ASL*: Affected Limb, UNAFFL**: Unaffected Limb, MD: Mean difference, SD: Standard Deviation, NS: Statistically Non-Significant. P<0.05* shows a statistically significant result

Table. 3. - Pre and Post Intervention Level Scores for Group A

*Abbreviation: S: Statistically Significant, NS: Statistically Non-Significant

P<0.05* shows a statistically significant result.

Table. 4: - Pre and Post Intervention Level Scores for Group B

*Abbreviation: S: Statistically Significant, NS: Statistically Non-Significant

P<0.05* shows a statistically significant result

Table 5: -Post-Intervention Level Scores of Group A and Group B

*Abbreviation: S: Statistically Significant, NS: Statistically Non-Significant

P<0.05* shows a statistically significant result.

Discussion

The present study aimed to find a promising intervention technique from Manual Perturbation and Proprioceptive Neuromuscular Facilitation for improving Trunk Stability & Lower Extremity Function in post-stroke.

The present study showed no significant difference in the pre-treatment mean scores for both groups, which showed that both groups matched the baseline level (Table 2).

The manual perturbation group showed a significant difference between its pre- and post-intervention in the Trunk impairment scale (TIS), Timed Up and Go test (TUG), Dynamic Gait Index (DGI), Cadence, Affected & Unaffected Side Step Length (UNSL) Affected & Unaffected Side Stride Length respectively (Table 3).

TIS consists of the activity of static balance, dynamic balance, and coordination of the trunk; manual perturbation has proved to be effective in improving balance and coordination of the same. It can be because perturbations utilize resistance as one of the components, which leads to the co-contraction of the trunk muscles of both sides (affected and Sound), which improves coordination of the trunk muscles when the perturbation is applied. Coordinated working of the muscles, which is badly affected on the paralytic or paretic side of hemiplegic patients after stroke, is very important in producing a meaningful movement. Thus, resistance that is utilized to produce the contraction isometrically facilitates coordinated activities of both sides of trunk muscles, improves proprioception, and strengthens the weaker muscles by producing irradiation and spread of muscular activity to the weaker ones.[23] Manual perturbation training applies a similar principle where an unexpected external or internal force is applied through the shoulder, trunk, and pelvis, thus recruiting core muscles and improving trunk stability. [24]

According to Dr. Robert Donatelli, perturbation enhances the ability of the proprioceptive signals to the muscles, prevents falls, and enhances performance in an athlete. [33] Since in stroke, proprioception is affected too, manual perturbation training can improve the balance.

Timed up and go test (TUG), on the other hand, works on dynamic balance and functional movement with time. It requires both static and dynamic balance. Dynamic Gait Index (DGI) is also important in measuring mobility, mobility function, and one's ability to modify gait in response to changing task demands. Thus, the improvement in these outcome measures could be due to the repeated exposure of the individual to applied balance disturbances, which in turn helps in improving the control of fast reactive movements and postural reactive balance, enabling the individual to perform a meaningful task & modify accordingly. [26, 27, 28, 29].

Gait parameters like cadence affected and Unaffected limb step length & stride length showed a significant difference pre-and post-intervention. This could be due to improved muscular strength, balance, and proprioception. A study by Yu-Hung Park et al. on "An ankle Proprioceptive control program improves balance, gait abilities of chronic stroke patients" shows that improvement in muscle strength and proprioception improve the cadence and gait symmetry in the stroke population. [39] There are various studies on stroke, as well as other neurological disorders, that show a significant difference in step and stride length following perturbation training. [30,31, 33, 34, 35, 36, 37]

Improvement in the TIS, TUG, DGI, and Gait Parameters like Cadence, affected, unaffected side step length & affected, unaffected side stride length can be because PNF helps in the improvement of the functions of the muscles and tendons by stimulating the Proprioceptive sense, which enhances muscle strength, flexibility, and balance. Trunk pattern exercises, pelvic patterns, and lower limb patterns increase trunk stability, coordination, and balance. All these patterns are diagonal & Rotatory in nature, so the patients have to use both sides of the trunk muscles to complete the resistance provided against the trunk, pelvis, and lower limb, causing irradiation in the weaker muscles, which facilitate activities of sound as well as the affected side of the muscles. It also uses various facilitatory methods like the stretch, approximation, verbal and visual cues, and specific patterns, which not only facilitate the activities of weaker muscles but greatly improve coordination and proprioception, normalize muscle tone, and improve voluntary muscle control. [13,14,15]

Improving proprioception and voluntary muscle control improves gait patterns, stability, and functional mobility.  However, only some studies have investigated improved trunk control and gait parameters in stroke patients using the PNF approach. [38, 39,40]

While comparing the results of the two groups post-intervention level, the PNF group improved in TUG and Step length of the Unaffected side, a component of gait parameters statistically. Still, it did not show a statistically significant difference in TIS, DGI, step length of the affected side, and stride length of the affected and unaffected limb, which implies that both techniques have almost the same effect in improving trunk stability and lower extremity functions. The improvement in TUG & Unaffected side step length may be due to the combined effect of trunk, pelvic, and lower extremity PNF patterns, which helps improve movement, stability, Mobility, and skills level as compared to Manual Perturbation which works mainly on stability & Mobility components. Studies by S. Karthik Babul 2011, Ray Wang 1994, and Kumar S. 2012 state that balance in the trunk and pelvis will lead to an improvement in gait or lower extremity functions, thus supporting the present study. [8, 15, 22, 25]

This study didn't support the hypothesis that manual perturbation is better than the Proprioceptive Neuromuscular Facilitation Technique in improving trunk stability and Lower Extremity function, so the alternative hypothesis was rejected, and the null hypothesis has been accepted.

The study confines to limitations like:

• The absence of a control group was one of my significant limitations. Since there was no control group, the improvement in balance and mobility could be due to conventional Physiotherapy,
• A specific stroke that involved only the lower extremities couldn't be taken.
• Less sample size of the study.
• No follow-up.
• Too many parameters were included in the study, which was time-consuming and, at the same time, tiresome for the patient.
• Since the study was multi-centered thus, randomization wasn’t consistent.

Clinical Relevance: - This study's results have shown no significant difference between the two interventions except TUG & Unaffected Step length. Both techniques proved effective and can be combined in the future to improve trunk stability and lower extremity function in individuals with post-stroke conditions in addition to conventional therapy.

Future Recommendation

1)  Future studies can include a larger sample size.

2)  These approaches can be used to study other neurological conditions like head injury, Cerebral Palsy, and Parkinson’s Disease.

3)  Components like the symmetry of step length can be further investigated.

4)  Correlation between trunk, pelvic, and gait can be further studied.

5)  Single limb support can be further investigated as almost all the subjects faced more difficulty crossing obstacles with the affected leg on the ground than with other activities.

Conclusion

Considering all the outcome measures, it can be concluded that both Manual Perturbations and PNF are equally effective in improving trunk stability and lower extremity functions except TUG & Unaffected side step length. Thus, if both approaches are used simultaneously, a better result can be obtained in a shorter time.

Ethical Approval

The study was registered and approved by the Institutional Ethics Committee of the Department of Physiotherapy, SAHS, School of Medical Sciences & Research, Sharda University & Sharda Hospital. CTRI no of the study is CTRI/2023/07/054754.

Conflict of interest

The authors declared no conflict of interest.

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