The Role Of Proprioceptive Neuromuscular Facilitation Stroke
Stroke is a "rapidly developing clinical signs of focal disturbance of cerebral function, lasting more than 24 hours or leading to death with no apparent cause other than that of vascular origin" (Aho K Harmsen 1980). Stroke is a disease of developed nation and it's the third leading cause of death and long term disability all over the world with an incidence rate of 10 million per year (Sudlow and Warlow 1996). Stroke occurs at any age but it is more common in elderly between 55 to 85 years of age (Boudewejn Kollen and Gert Kwakkel 2006).
Stroke is classified into two types based on the pathology and cause, Ischemic stroke, occurs when the blood supply to part of the brain is decreased, leading to dysfunction of the brain tissue in that area. The ischemia results when there is Thrombosis, Embolism, Systemic hypoperfusion and venous thrombosis. Hemorrhagic stroke occurs when there is accumulation of blood anywhere within the skull vault. These hemorrhage results when there is microaneurism, arterio venous malformation and inflammatory vasculitis (Capildeo and Habermann 1977).
Normal cerebral blood flow is approximately 50 to 60 ml/100g/ Minutes and varies in different parts of the brain. When there is ischemia, the cerebral auto-regulatory mechanism will compensate for the reduction in the cerebral blood flow by local vasodilatation and increase the extraction of oxygen and glucose from the blood. When the Cerebral Blood Flow is reduced to below 20 ml/100g/min, an electrical silence occurs and synaptic activity is greatly diminished in an attempt to preserve energy stored. Cerebral blood flow of less than 10ml/100g/min results in irreversible neuronal injury. These neuronal injuries occurs when there is formation of microscopic thrombi, these microscopic thrombi are triggered by ischemia induced activation of destructive vasoactive enzymes that are released by endothelium, platelets and neuronal cells. These result in the development of hypoxic ischemic neuronal injury which is primarily induced by overreaction of some neurotransmitters like glutamate and aspirate. Within an hour of hypoxic-ischemic insult there will be ischemiec penumbra where auto- regulation is ineffective. This stage of ischemia is called window of opportunity, where the neurological deficit created by ischemia can be partly or completely reversed. After this stage is a stage of neuronal death, in which the deficit is irreversible (Heros 1994).
Functional restrictions resulting from stroke are paralysis of upper limb & lower limb function, cognitive deficit, visual disturbances, disturbance of gait and mobility, spasticity of muscle, loss of co-ordination and speech problems. The loss of upper extremity control is common after stroke with 88% of survivors having some level of upper extremity dysfunction. Basic Activities of Daily Living (ADL) skills are compromised in acute stroke, with 67% to 88% of patients demonstrating partial or complete independence (Amit Kumar Mandall 2009). Muscle weakness, or the inability to generate normal levels of force, has clinically been recognized as one of the limiting factors in the motor rehabilitation of patients with stroke. Following stroke, some patients lose independent control over select muscle groups, resulting in coupled joint movements that are often inappropriate for the desired task. These coupled movements are known as synergies and, for the upper limb flexor synergy: shoulder flexion, adduction, internal rotation, elbow flexion, wrist flexion and finger flexion. Upper limb extensor synergy: shoulder, elbow, wrist and finger extension.
The rehabilitation of upper extremity is quite challenging. Many therapeutic approaches are currently available in the rehabilitation of upper extremity function. Most commonly used treatment approaches are ROODs approach, Sensory motor approach, PNF, Brunnstroms movement therapy, Bobaths technique and neuro developmental therapy. In this Proprioceptive Neuromuscular Facilitation (PNF) is widely used in the rehabilitation of upper extremity function in stroke patients. (Amit Kumar Mandall 2009).
PNF is a therapeutic intervention used in rehabilitation which was originally developed to facilitate performance in patients with movement deficits. PNF exercises are based on the stretch reflex which is caused by stimulation of the Golgi tendon and muscle spindles. This stimulation results in impulses being sent to the brain, which leads to the contraction and relaxation of muscles. When a body part is injured, there is a delay in the stimulation of the muscle spindles and Golgi tendons resulting in weakness of the muscle. PNF exercises help to re-educate the motor units which are lost due to the injury. A variety of methods fall under the rubric of PNF, including the exploitation of postural reflexes, the use of gravity to facilitate movement in weak muscles, the use of eccentric contractions to facilitate agonist muscle activity, hold relax, contract relax, rhythmic stabilization, rhythmic initiation and the use of diagonal movement patterns to facilitate the activation of bi-articular muscles (Etnyre & Abraham L D, 1987; Hardy & Jones, 1986 Osternig, Robertson, Troxel, & Hansen, 1987).
TomaszÂ Wolny, EdwardÂ Saulicz and RafaÅ‚Â Gnat in 2009 conducted a randomized control study on the efficacy of proprioceptive neuro-muscular facilitation in rehabilitation for activities of daily living in late post-stroke patients. In this study sixty four stroke patients were recruited from the neurological rehabilitation centre Subjects for this study were recruited based on some inclusion criteria. The patients with loss of sphincter control, loss of mobility, locomotion and communication were included in this study and patients with grade 5 or 6 'Repty' Functional lndex scale were included in this study. After the recruitment of patients, all the 64 patients were randomly divided into two groups, group A (control group) and group B (experimental group). Group A will receive conventional treatment like strengthening, gait training etc. Group B will receive PNF based exercise. A pre and post assessment of the functional status of the stroke patients was done using 'Repty' Functional lndex scale. The treatment will be continued for 21 days for both the groups in the neurological rehabilitation centre. . The data were analyzed using chi-square test. Chi-square was used to study associations between the treatments and changes in the criterion measurements. ANOVA was used to compare the average changes among the two groups. The result of this study showed that PNF-based rehabilitation exercise of late post-stroke patients significantly improved in their ADL functional performance and in locomotion when compared to the control group treated with conventional therapy.
Kuniyoshi Shimura.A, Tatsuya Kasai. B in 2002 conducted a study on Effects of proprioceptive neuromuscular facilitation on the initiation of voluntary movement and motor evoked potentials in upper limb muscles activity. In this study author investigated the effect of PNF limb positions and neutral limb positions on the initiation of voluntary limb movement and motor evoked potentials in upper limb muscles. In this experimental study the patients were divided into two groups, in experimental group 1 they investigated the effectiveness of PNF by considering the effects of limb position changes on the initiation of voluntary movement in terms of electromyographic reaction times. In experimental group 2 they investigated the effectiveness of no (neutral limb position) movement by considering the effect of limb position changes on the initiation of voluntary movement with electromyographic reaction times. After signing the consent the experiment was conducted on the patients. Two upper arm positions used in this study, a neutral position (N) and a position facilitating activity of the upper extensor muscles (PNF). The effects of these positions are observed in the EMG. The subject could passively adopt the two upper arm positions using his right (affected) arm by means of especially made arm holders. For each arm position, six blocks of 10 trials were performed. All trials of the first
block and the first trial of each of the following blocks were excluded from the analysis to eliminate start-up effects. In addition, a few trials were discarded because of obvious mistakes in the recording. EMGs were recorded simultaneously from three muscles (Brachioradialis, triceps brachii and deltoid) using 3 cm diameter, bipolar, silver surface electrodes connected to an EMG-unit.
The result of this study showed that the EMG discharge order differed between the two positions. PNF position improves movement efficiency of the joint by inducing changes in the sequence in which the muscles are activated. Hence PNF has an effective role in the initiation of voluntary movement and motor evoked potential in upper limb muscle activity.
Pamela Duncan and Lorie Richards et al., in 1998 conducted a study on the effect of Home-Based Exercise Program for Individuals with Mild and Moderate Stroke. In this randomized controlled pilot study, 20 individuals with mild to moderate stroke who had completed acute rehabilitation program and those who were 30 to 90 days after onset of stroke were randomized to a 12-week (first 8-week will be therapist-supervised program and the next 4-week will be independent program) rehabilitation program. After signing the consent form, patients were selected based on some inclusion criteria like (1) 30 to 90 days after stroke; (2) minimal or moderately impaired sensorimotor function (3) ambulatory with supervision and/or assistive device; (4) living at home; and (5) living within 50 miles of the University. The exclusion criteria for this study are (1) a medical condition that interfered with outcome assessments or limited participation in sub maximal exercise program, (2) a Mini-Mental State score <18 and (3) receptive aphasia that interfered with the ability to follow a 3-step command.
The participants for this study were selected and evaluated by a therapist based on the inclusion and exclusion criteria. If the subjects agreed to participate in this study, then the basic assessment is done after getting the informed consent. The severity of the stroke were assessed using Orpington Prognostic Scale (Sue-Min Lai and Pamela W. Duncan 1998) and Fugl-Meyer Motor Score (Pamela W Duncan 1982) that includes assessment of motor function of the arm, upper extremity proprioception, coordination, balance, and 10 cognitive questions. The functional assessments are performed using Barthel Index Activities of Daily Living (Fricke and Unsworth 1997) Lawton Instrumental Activities of Daily Living and Medical Outcomes Study-36 Health Status Measurement (Colleen and John 1992).
Functional assessments of balance and gait of the participants were assessed using 10-Meter Walk, 6-Minute Walk (Kosak and Smith 2005) and Berg Balance Scale (Berg, Wood-Dauphinee and Williams 1995). Upper extremity hand function was evaluated with the Jebsen Test of Hand Function.The Jebsen is a standardized assessment to measure the time taken to perform hand activities. These includes: writing a short sentence, turning over 3x5 cards, picking up small objects, stacking checkers, simulated eating, moving empty large cans, and moving weighted cans(Jebsen, Taylor, Trieschmann 1969).
After baseline assessment the subjects were randomly assigned into two groups, experimental group and control group. In experimental groups the PNF exercise were taught to the patients on day one as an home exercise and they were asked to continue the same exercise as an home program for eight weeks with three visits to the physical therapy department every week. The exercise includes assistive and resistive exercises using Proprioceptive Neuromuscular Facilitation Patterns and Theraband exercise to the major muscle groups of the upper and lower extremities. Subjects in the control group received usual care as prescribed by the physicians. The subjects of this group were assessed by the research assistant.
The demographic data of both the groups were statistically compared using Wilcoxon rank sum tests. The results of this study showed that there is no difference in the pre and post exercise treatment. There is no change in the upper extremity function and the functional health status in both the experimental group as well as in control group after the treatment interventions.
Ruth Dickstein, Shraga Hochman, Thomas Pillar, and Rachel Shaham in 1992 conducted a study on Stroke Rehabilitation with Three Exercise Therapy Approaches. One hundred and ninety-six hemiplegic patients were randomly selected for this study. All subjects were referred to the physical therapy department of a geriatric-rehabilitation hospital over a period of 18 months were admitted to the study. All patients had a recent cerebrovascular accident and came for a rehabilitation program after an average stay of 16 days in a general hospital. Sex distribution was equal with a mean age of 70.5 years. Thirteen physiotherapists were enrolled in the study for exercise administration and the subjects were assigned randomly to each therapist. The data were collected in a separate form, which has two parts; first part was used to collect the basic information like age, gender, side affected and location of the damaged artery. The second part was used to record the variable data. Each therapist treated their first five patients with conventional method, next five with PNF method and the last five with Bobath method. All patients were treated for five days a week for six weeks, and each treatment sessions were last for 30 to 45 minutes.
The outcomes of each patient are measured before the treatment and every week thereafter. The functional independence is measured with Barthal index. Muscle tone of the involved extremities
was checked by passive movements of the extremities with the patients in supine position. Muscle tone was graded using an ordinal scale composed of five points: a) flaccid, b) low, c) normal, d) high, and e) spastic. Ambulatory status of the patient was assessed and classified with a nominal four category scale: a) patient does not walk, b) patient walks with an assistive device and person's help, c) patient walks with an assistive device, and d) patient walks independently. The treatment was continued for 6weeks in both the groups. The data were analyzed using chi-square test. Chi-square was used to study associations between the treatments and changes in the criterion measurements. The Kruskal-Wallis one-way analysis of variance (ANOVA) was used to compare the average changes among the three groups.
The results of this study showed that there is no significant difference in the improvement of activities of daily living and in the walking ability. But there is significant difference in the improvement of muscle tone in PNF group and in Bobath group when compared to the conventional treatment group.
The poor quality of the trials reviewed severely limits the conclusions that can be drawn. However, it seems that currently there is no evidence, that interventions based on the Proprioceptive Neuro-muscular Facilitation (PNF) are more effective than other approaches. One Study done by Ruth Dickstein on PNF vs. Bobath concluded that PNF exercise given in conjunction with Bobath technique are more effective in improving wrist strength and upper limb function than giving PNF alone. But the outcomes used in these studies are ordinal rating scales, which may not be sensitive enough to differentiate the effect of the two techniques. The number of subjects recruited for these studies is very less. We cannot come to conclusion on the effect of PNF in upper limb function with these less number of studies.
Stroke patients may vary widely on factors such as physical impairments, speech impairments, severity of impairments, cognitive impairments, and also in the individual personality and learning styles. So, we cannot assume that this PNF technique is superior to all other techniques, because we cannot say this technique can be used in individuals with stroke and at every stage of recovery. For example one approach may be effective in initial stage of stroke, but the same approach may not be effective for chronic stroke patients. Factors such as depression, spatial awareness, cognition, comprehension and sensory loss could also have an impact on the response of a technique.
In most of the studies there is no exact clinical finding about the problem, size of lesion and the site of lesion. Characteristics of the lesion may explain the variability in responsiveness to the intervention. There is no ideal timing of the interventions, whether the technique should be given in the initial stage or late stage of stroke.
In this review on the effect of PNF in upper limb function in stroke, evidence on the current practice is lacking. Because of the lack of evidence on current practice it is very difficult to make a conclusion. Evidence of support and treatment used in these articles is not standard to use in today's health care practice. It is suggested that further studies comparing the effect of PNF with other approaches using sensitive, reliable outcome measures and with homogenous sample size should be done. Therefore it is important that future studies clarify the analysis and interventions used within the PNF technique to enable accurate evaluation of the study. No studies on this review assessed the efficacy and the effectiveness adequately, so further studies should be done to get an effective and optimal approach in the rehabilitation of upper limb function in stroke patients.
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