Here, we report a case of a PD patient with AC and CC as the primary symptoms, who showed significant relief in abnormal posture and a great improvement in quality of life after sensory tricks and trunk strength training. To the best of our knowledge, this case is the first reported case of rehabilitation method for AC. In addition, gait analysis was used to assess the improvement of balance and walking ability objectively. The gait speed and other gait data measured in gait analysis can be used as a sign of disease severity in PD patients[20]. Although there are challenges in measuring the anterior flexion of the cervical, thoracic, and lumbar spine. The author still found a Neuro Posture App method to compare the changes of the corresponding angle before and after treatment.
There are many causative factors in AC and CC, and the mainstream view is that pathogenesis can be divided into central and peripheral mechanisms. The central mechanism is exercise-induced dystonia, a disease of the striatum and its projection to the reticular spinal tract or thalamus in PD patients, clearly represented by abnormal trunk posture[21]. In addition, the spinal cord's multisynaptic reflex arch integrates sensory information into the motor output. Sensory input comes from Golgi tendon organs, muscle spindles, and articular receptors. Their information is integrated into the motor output and raises awareness so that it can voluntarily influence the motor output. The sense of joint position, movement, and muscle strength are part of our self-consciousness or proprioception. Central and peripheral mechanisms produce proprioceptive disorders. The central mechanism is associated with the progression of PD. Peripheral muscle stiffness due to aging leads to the degeneration of paraspinal muscle groups. Both conditions result in characteristic pathological changes in the axial musculature that maintains upright body posture and result in abnormal axial trunk posture[22]. In addition, Tiple et al. found that a history of spinal surgery induces CC[10]. Srivanitchapoom et al. found that drug factors are causative factors in AC and CC[23].
In terms of central mechanism, we used two sensory tricks methods due to the patient's dystonia while standing or walking. One is the a weighted backpack. The backpack generates proprioception and light touch input to the patient, increasing the integration of sensorimotor function[24]. Studies have shown that higher beta waves increase the severity of PD. Thus, effective treatment is needed to reduce beta waves generated by central vibrations[25]. Peripheral sensory input given by inexpensive backpacks may impact the central network, reducing abnormal movements due to dystonia[26]. Second, a HFW is recommended, which can be used as a motor trick to provide continuous proprioception to PD patients while walking. As a behavioral strategy, it can be taught to both the patient and the caregiver[27]. In addition, this HFW, which is a light portable walker, can be used for activities at home and work[28].
Peripherally, trunk muscle training reduces the risk of falling[29]. Trunk strength can be improved because it plays a role in stabilizing the head in dynamic tasks. In back muscle training, we targeted paraspinal muscles and other back extensors, such as latissimus dorsi. These exercises increase the patient's strength to maintain an upright posture. In abdominal muscle training, training targets the patient's internal and external oblique muscles and can improve forward flexion of the upper trunk. Second, the rectus abdominis and iliopsoas muscles are trained to improve forward flexion of the lower trunk[23]. Training these core muscles simultaneously can improve transferring from supine to sitting. During the training, the author asked patients to use rhythmic auditory stimulation software (metronome) with visual conduction to enhance visual and proprioceptive input and strengthen the cervical muscle. Adjustment of trunk posture is performed by positive feedback[30]. Trunk stretching is a static stretch that increases tendon length immediately, improving the relationship between muscle tone and tendon length. It alters the viscoelastic function of muscles. Therefore, it can reduce muscle motor neuron hyperexcitability by modulating spinal cord suppressor neurons[31, 32]. As a result, stretching helps the patient improve her stiffness in the trunk muscles.
Marialuisa et al. used proprioceptive and visual feedback as the primary spinal posture correction training to improve the postural control and trunk forward flexion of patients with PD posture abnormalities. They found that patients decreased 8.84° in trunk forward flexion angle and a 4.94 point reduction on the UPDRS-III [33]. They used peripheral mechanism methods to improve the patient’s posture and motor abilities. Meanwhile, the central mechanism seems to have an effect on treating PD patients with posture abnormalities. The study applied an HFW as a central mechanism method. Frauke et al. recruited 20 CC patients using an HFW to accomplish upright standing and walking. The author claimed therapeutic effects according to the report. However, the treatment was not controlled to other treatments and the duration was 3–7 days[34]. The study had sufficient patients to facilitate but was poor in the short duration of the treatment. We learned from these two studies and thought that the combination of central and peripheral mechanism methods would help the patient improve her function better. As a result, our study showed the patient’s angles of AC, Upper CC, and Lower CC decreased by 76.2°, 25°, and 16°.
Similarly, Byung Kook Ye et al. reported one CC case. The patient wears a heavily loaded backpack, cruciform anterior spinal hyperextension brace, and back extensor strengthening exercises[35]. Kun Hee Lee et al., in the same hospital, recruited 9 CC patients to investigate conservative treatment effects. They added core muscle training and a low-slung backpack to the patients. The author reported an overall improvement in activities of daily living and motor movement[36]. In the case we report, we provided comprehensive assessment tool results and detailed gait analysis data and images to record the improvement of the patient’s function.
Notably, we found that the angle of AC improved even more than the angle of CC. In searched articles, treatments for AC have mostly been found by reducing drugs such as donepezil and dopaminergic agonists such as pramipexole[11, 37, 38]. Though decreasing pramipexole for patients in the literature is also used and thought to relieve symptoms, this drug is crucial for symptom control in PD patients, and therefore reduction is not considered. Besides, there is no such typical literature on AC rehabilitation, our study methods may have positive effects on PD patients with AC.
The present study has several limitations. First, Parkinson's medication switch on/off was not set in the treatment. Thus, the patient was evaluated under the condition of medication. Second, a single case is not universal. We should increase the number of cases. Further studies are required to confirm the effectiveness of therapeutic interventions.