The Effect of the Activation of the Core Muscles on Tremor in a Patient with Multiple Sclerosis
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.333519
Source of Support: None, Conflict of Interest: None
Keywords: Ataxia, core muscles, multiple sclerosis, rehabilitation, tremor
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterized by myelin, oligodendrocyte, and axon damage. MS affects approximately 2.5 million people in the world and is observed 2-3 times more in females than males. Although there are many specific symptoms for MS, tremor is a common finding.
Trunk stabilization is very important for the proper control of balance and extremity movements. Among the muscles that ensure this stabilization are the transversus abdominus, multifidus, diaphragm, and pelvic floor muscles. These stabilizing muscles, which are known as the “core” region and surround the body like a corset, are activated in the anticipatory postural adjustments before extremity movements and stabilize the extremity movements to be made.
Postural control deficiencies that occur during voluntary movements and incoordination, which is defined as ataxia, are characterized by postural control, balance, and extremity ataxia. The rate of extremity ataxia affecting the voluntary movement smoothness is 25% on average in MS patients. The most common finding in extremity ataxia is tremor. Upper extremity tremor is observed in approximately 50%-75% of MS patients, and tremor leads to disability in 27% of these patients.
The performance-based measures such as the “International Cooperative Ataxia Rating Scale” (ICARS), “Scale of Assessment and Rating Ataxia” (SARA) and Friedreich's Ataxia Rating Scale” (FARS) can be used to evaluate ataxia. However, these scales roughly evaluate upper extremity ataxia with 1–2 items, and the remaining items focus on the other components (walking, trunk, etc.) of ataxia. In addition to performing timed- performance tests such as the nine-hole PEG test, Purdue Peg Board, Box-and-Block test there is not a specific clinical test that directly focuses on upper extremity ataxia., On the other hand, the tremogram used in the objective evaluation of upper extremity ataxia records the tremor frequency (Hz) and amplitude on the EEG polygraph with the help of an accelerometer connected to the index finger.,
It is observed that the number of studies conducted on the effect of core stabilization exercises on the upper extremity functions in the literature is insufficient.
The aim of the present report is to investigate the effect of the contraction of the cervical and lumbar core muscles on tremor, which is one of the components of upper extremity ataxia, by using clinical and electrophysiological tests.
The evaluation of the patient was done in the Neurological Rehabilitation Unit of Hacettepe University, Faculty of Health Sciences, Physical Therapy and Rehabilitation Department.
The patient was 22-year-old male diagnosed with relapsing-remitting MS 2 years ago, treated and followed-up at Hacettepe University, Department of Neurology. A written informed consent was obtained from the patient.
Expanded disability status scale (EDSS)
It is a scale determining the level of disability of MS patients and scoring it between 0 and 10.
This performance-based scale consisting of 8 items is used in the evaluation of ataxia. The items consist of the parameters of gait, stance, sitting, speech disorder, nose- finger test, finger-chase test, fast alternating movements, and heel-shin test. Since the 5th and 6th items are related to the kinetic extremity functions, they are evaluated bilaterally. The item 5-6 of this test evaluating upper extremity intentional tremor was repeated 2 times by contracting the deep neck and trunk muscles.
In this test, postural tremor was evaluated by the accelerometer detecting two-dimensional non-invasive axial movements and attached to the fingertip of the patient in the rest position [Figure 1].
The patient was evaluated in two positions. Two-minute recording was taken in Position 1: when the arms were parallel to the floor and the elbow was in extension, and in Position 2: When the elbow was in flexion in a way that the fingertips were pointing at each other [Figure 2].
The frequency analysis of tremor and the evaluation of harmonics, the measurement of noise ratio and amplitude values were analyzed by using the spectral analysis in the computer. The test was conducted two times by contracting and without contracting the deep neck and trunk muscles.
Purdue pegboard test
The test protocol was applied in a way that the patient places first a pin, a rove, a bead and a rove as described. Completing each pin, washer, collar and washer pattern without mistakes was accepted as 1 successful point. It was evaluated how many successful pin-rove-bead-rove assemblies placed on the board in a minute the test was conducted in two ways by contracting and without contracting the deep neck and trunk muscles, and the value with the best performance was recorded after three successive repetitions.
Firstly, the patient was provided with training on the contraction of deep cervical and lumbar muscles for a week. One week later, the evaluations were performed firstly without contracting core muscles and then during contractions.
Clinical and demographic characteristics
The patient's age was 22, height was 180 cm, weight was 61 kg and the disease duration was 2 years. EDSS score of the case was 2.5, and the Mini-mental test score was 30. The patient was able to perform daily living activities independently experienced mild-to-moderate difficulties in fine motor skills due to extremity ataxia. He had intentional tremor/dysmetria in the right side of upper extremity and postural control problem which was evaluated with SARA. He had only slight difficulty in taking 10 consecutive steps in the tandem position. He could stand without swinging his feet adjacent. However, he could not remain in the tandem position for more than 10 s. He could sit without support for a long time. There was no spasticity and muscle weakness in the extremities of the patient. The patient had a slight speech disorder and did not have any sensory problems.
While the value of the SARA, which is a scale used to evaluate ataxia, was 16 without contracting, the total value decreased to 14. There was one-point decrease with contraction in both 5th and 6th items including the upper extremity intentional tremor evaluation. The distance to reach the target was less than 15 cm, with the contraction, this distance became less than 5 cm. And while finger nose test (6th item of SARA) the amplitude of his tremor was less than 5 cm without contraction, the amplitude of his tremor decreased below 2 cm with contraction.
According to the tremogram results, a decrease occurred in the tremor amplitude both in the 1st and 2nd positions with the contraction of the deep cervical and lumbar muscles. While the tremor frequency was 6 Hz and the amplitude was -14.6 in the 1st position before contraction, the amplitude became -18.3 after contraction [Figure 3]. On the other hand, it was determined that 6 Hz tremor disappeared after the evaluation performed with contraction in the 2nd position.
Purdue pegboard test
According to the results of the Purdue Pegboard test, the right extremity performance was 5 and the left extremity performance was 6 in the tests conducted without contraction. According to the result of the test conducted with contraction, the right extremity performance reached the level of 7 of non-ataxic extremity performance. Left extremity performance was 7 and there was an increase in the upper extremity performance.
This report contains results that offer a different perspective on the rehabilitation of MS patients with upper extremity ataxia. It was demonstrated with clinical and electrophysiological tests that the single-session contraction of the deep cervical and lumbar muscles reduces upper extremity tremor in an RRMS patient who has not received spinal stabilization exercise treatment.
It has been shown in the previous studies that there is an increase in the strength and range of motion in extremities together with the increase in the strength of the spinal stabilization muscles. However, no study determining its effect on upper extremity tremor was encountered. This is the first report of such an effect.
Miyake et al. evaluated the upper extremity functions with the Purdue Pegboard test in the report they conducted on 40 healthy individuals reported that single-session spinal stabilization exercises increased the upper extremity functions. While healthy individuals could place 30 pins on average before the exercise, this number increased to 34 on average after the exercise. The pin-rove-bead-rove pattern of the case in the present report was accepted as one successful task, and 2 more patterns were performed when the core muscles were contracted. Moreover, an increase occurred in the ataxic right extremity performance as a result of the evaluation performed during the contraction of core muscles and it was balanced with the non-ataxic extremity performance, and 7 of each pin-rove-bead-rove patterns could be performed. This result supports the results of the report conducted by Miyake. There is no other study and report in the literature with which we can compare the results of the present report.
It is not possible to mention the whole mechanism related to how the spinal stabilization muscles affect the upper extremity functions. However, it is known that proximal stabilization improves distal stability and upper extremity movement control. Multifidus in the lumbar region, pelvic floor, diaphragm, transversus abdominis, and deep cervical flexors and multifidus in the cervical region form the basis for movement. The correct and smooth contraction of these muscles is considerably important for the smoothness of movements in extremities. The core region is the key point for locomotion and upper extremity skills. Therefore, these exercises should be considered as a neuromuscular facilitation technique rather than a strengthening program. In the present report, a decrease observed in intentional tremor and an increase observed in the upper extremity skills even in a one-time contraction. It is believed that core stabilization exercises added as a complement to physiotherapy programs may have a different direction to the treatment of patients.
This case report had some limitation. It was thought that it was not possible for the patient to perform muscle contraction without getting exhausted and losing concentration for two minutes with one-week training and the patient was supported with verbal warnings when muscle contraction deteriorated. The evaluation of the contraction of core muscles can be performed while in the supine position with the help of a stabilizer. However, the stabilizer was not used since the patient was supposed to be evaluated in the sitting position according to the recording principle and the implementation position of the performance tests. On the other hand, it was considered to use superficial EMG to evaluate whether contraction was performed objectively. However, it was not performed since the mentioned muscles were deep and it was not possible to make recording with superficial EMG. Purdue pegboard test results affected by fatigue and muscle weakness. Our patient had no muscle weakness but we did not assess motor fatigue. The motor fatigue should be evaulated and should be take into consideration when interpreting the results. Another limitation is that the assessment is performed on only one case and the results may be coincidence. Therefore, future studies are needed with larger sample size.
The deep cervical and lumbar region muscles increase the stabilization of the body and improve the upper extremity functionality. This result revealed in a single patient cannot be generalized. Therefore, on the basis of the present report it is thought that a long-term deep cervical and lumbar region exercise program may provide a positive contribution to upper extremity tremor and functional capacity in patients with upper extremity ataxia in the future studies.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3]