Effect of Task-Oriented Exercises With and Without Altered Sensory Input on Balance and Falls in Subjects with Parkinson’s Disease

Introduction

Parkinson’s Disease (PD) is a progressive neurodegenerative disorder usually presenting in the later years of life. The condition is due to selective neuronal loss of substantia nigra and a decrease in dopamine production in the basal ganglia.¹ It was reported that an estimated 10 million people in the world (i.e. approximately 0.3% of the world population) and 1% of those above 60 years are found to be affected with PD.

PD is characterized by different motor symptoms like akinesia, bradykinesia, tremor and rigidity. These subjects have other motor difficulties like disturbances in gait, handwriting, grip force and speech, among others.² PD is characterized not only by its motor aspects, but also by numerous non-motor symptoms that encompass sensory abnormalities, behavioural changes, sleep disturbances, autonomic dysfunction, and some more difficult to categorize symptoms such as fatigue.³

Literature review suggests that balance dysfunction and related falls are common in subjects with Parkinson’s disease, and the fall risk increases with disease progression without appropriate and vigorous interventions to address the risk of fall.⁴ Postural instability is another cardinal sign of Parkinson’s disease that can lead to increase in the fall risk. Postural instability can be defined as the ability of a person to maintain balance in static postures and during dynamic activities. It has a large impact on quality of life, independence, and community participation. Factors that are associated with postural instability include difficulties in anticipatory and reactive responses to perturbations, disturbed vestibular sensory input and sensory-motor integration, impaired kinaesthetic senses during active postural stability control, latency of polysynaptic spinal stretch reflexes, latency and rigidity, and impaired cognition.⁵

Physiotherapy programs aim to maximize functional ability and to minimize secondary complications through movement rehabilitation.⁶ Task-oriented training involves a variety of practices to help patients derive optimal control strategies for solving motor problems. During task-oriented training, different movements are practiced, mainly to limit compensatory movements and to increase adaptive movements. Task-oriented training is a method which focuses on specific functional tasks associated with the musculoskeletal and neuromuscular systems.⁷

Subjects with PD have difficulties with self-initiating a task and maintaining a steady task performance.⁸ Sensory processing impairments in PD likely contribute to poor balance control. Sensory attention focused exercise improves the ability to utilize proprioceptive information, resulting in improved balance control in individuals with PD.⁹

As suggested by various literature,self-initiating a task and maintaining a steady task performance is difficult in subjects with PD. Hence, specific practice is required for the desired function. So, there exists a need to find out the impact of task-oriented exercises with and without altered sensory input on balance and falls in subjects with Parkinson’s disease.

Methods

Participants

Thirty male and female subjects between the age group of 60-75 years diagnosed with idiopathic Parkinson’s disease were included in the study. Subjects were recruited from Padmashree Physiotherapy Clinic, Padmashree Diagnostics and ESIC Model Hospital, Bangalore. Participants were included in the study if they had moderate impairment (Hoehn and Yahr Scale – I-III), taking anti-parkinson medication at least for 3 years, had postural instability (Berg Balance Score – 4050). Subjects were excluded if they had any co-existing serious chronic medical illness, severe visual deficits, major depression, dementia or any other cognitive impairments or uncooperative subjects.¹⁰ Informed consent was obtained from the participants prior to the study. Ethical clearance was obtained from the Institutional Ethical Committee of Padmashree Institute of Physiotherapy. All the participants were assessed for balance and fall risk using Berg Balance Scale (BBS) and Falls Efficacy Scale –International (FES-I) prior to the intervention along with routine neurological assessment. BBS and FES-I were studied for their reliability and validity to assess balance and falls risk respectively.^{11, 12, 13} FES-I is an important fall-related psychological outcome and it can even predict future falls.¹⁴

Thirty subjects were randomly assigned into two groups, Group A and Group B through convenience sampling. Demographic variables such as age, gender, severity of the disease were documented. Participants in Group A received task oriented exercises with altered sensory input using foam and participants in Group B received task oriented exercises on stable surface. Participants in both the groups received the training for 1 hour, 3 times in a week for 6 weeks.

Protocol:¹⁵

•       On an exercise step, step forward, backward and sideways

•       Stepping over blocks of different heights

•       Rise up from a chair, take four steps forward, perform bilateral stool touch and walk backwards towards the chair

•       Stand from the chair, take four steps forward, turn right, step over the exercise step, turn right again and walk forward to the chair (repeat the exercise circuit in opposite direction)

•       Performing a 10 second double-legged stance

•       For 10 seconds, performing a tandem stance

•       Getting up from the chair without using the arms

•       Forward and backward walking in a tandem walking pattern

•       For 10 seconds, maintaining a single legged stance posture

First four exercises were performed on a stable surface for 20 minutes during each session and remaining exercises were done under the following conditions for 30 minutes during each session:

•       With eyes open on a firm surface

•       With eyes open on a soft surface (foam)

•       With eyes closed on a firm surface

•       With eyes closed on a soft surface (foam)

Finally, subjects completed their session with a 10 minute cool down period where flexibility and range of motion exercises were performed in sitting position.

Post intervention, balance and fall risk were assessed again using the same outcome measures.

Results

The distribution of the subjects with Parkinson’s disease according to their gender, age and disease severity is mentioned in Table 1. Data of the pretest and post-test BBS and FES-I scores were analyzed using Wilcoxin test for Group A and Group B and is given in Table 2 and 3 respectively. Table 4 explains the comparison of pre and post test BBS and FES-I scores in between the groups analyzed using the Mann-Whitney U test.

Discussion

This study intended to know the effect of task oriented exercises with altered sensory input and task-oriented exercises without altered sensory input on balance and falls in subjects with PD and to further compare the effect of task oriented exercises with and without altered sensory input.

Task-oriented training involves helping the patients derive optimal control strategies for solving motor problems. During task-oriented training, movements are practiced to reduce compensatory movements and to increase adaptive movements. It focuses on specific functional tasks associated with musculoskeletal and neuromuscular systems.⁷

Enhancing the utilization of intrinsic sensory feedback while exercising might alter cortical function through the release of neurotropic factors or neurotransmitters. Release of dopamine and neurotropic factors in PD could have helped in neural plasticity and repair. Recognizing the benefits of sensory information during exercise, task-oriented exercises with altered sensory input was developed to promote the utilization of proprioceptive information in PD.⁹

In this study, it was seen that both balance and falls in both the groups improved significantly. The results are in line with Mark A. Hirsch et al., who mentioned that muscle strength and balance can be improved in individuals with Parkinson’s disease by high intensity resistance training and balance training by reducing falls and improving equilibrium during destabilizing conditions. Balance training improves frequency and intensity of neuromotor pathways in controlling balance and furthering neuronal transmission and muscle contraction. Thus, motor programs used for balance adaptation can be better tuned or preset so to enhance transmission and execution.¹⁶ When both the groups were compared, subjects in Group A improved significantly than subjects in Group B. Using a foam challenges the proprioceptors could have resulted in better improvement in subjects in Group A. The results are in accordance to a study done by Jean Francois Bayouk et al., who compared the task oriented exercises with and without altered sensory input on postural stability in stroke subjects and concluded that taskoriented exercises assisted by sensory manipulation was more effective as it improved standing balance than a conventional task oriented program. Their results showed that addition of a multisensory training component to the regular exercise program was required to obtain a significant improvement in standing balance in stroke.¹⁵ Lefaivre et al. suggested that restricting vision during exercise might push the individuals to concentrate on the proprioceptive information and that can reduce the individual’s dependence on vision.⁹ Another study suggested that cueing exercises might lead to cortical reorganization to bypass the defective basal ganglia, and it appears as though the cued exercises were influencing neurophysiology that was more permanent while the non-cued exercises likely led to musculoskeletal improvements that were short-lived.¹⁷

Falls are one of the important causes of morbidity and disability in PD. The risk of falls is increased in individuals with Parkinson’s disease and the findings of several studies have revealed that 38% to 87% of subjects with PD experience fall. The present study showed significant improvement in reduction of falls in these subjects in both the groups and Group A improved better than Group B when the post test scores were compared. Performance of the exercise program results in improvements in freezing of gait and sit-to-stand time, as well as a trend towards improvement in overall falls risk, knee extensor muscle strength, fast walking speed, and fear of falling.¹⁸ Mon S. Bryant and colleagues in their study mentioned that poor gait and balance performance with greater fear of fall may be due to actual deficits from PD and fear of fall could modify gait and balance. Individuals might compromise their gait and balance due to fear of fall and also the impaired gait and balance from PD itself may lead to fear of fall.¹⁹ However, the long term effect of the exercise protocol was not studied due to time restraints. Future studies can look into the retention effect of the exercises to see how long the achieved results were maintained.

Conclusion

The present study was conducted to check the effect of task oriented training with and without altered sensory input on balance and falls in subjects with Parkinson’s disease and the results showed significant improvement in both the groups individually but the subjects who performed task oriented exercises with altered sensory inputs showed better improvement compared to the subjects in the task-oriented exercise program group without altered sensory inputs. Thus, it can be concluded that application of task-oriented exercises with sensory manipulation can be used clinically in managing Parkinson’s disease subjects to improve their balance and reduce falls and that it is a simple, time saving, cost effective method which can be done at home under the supervision and guidance of a caretaker.