Effects of osteopathic manipulative treatment vs. osteopathic cranial manipulative medicine on Parkinsonian gait

Subject recruitment and inclusion/exclusion criteria

The present study is a two-group, randomized controlled trial in which individuals with idiopathic PD (n=45) and age-matched healthy participants (n=45) were recruited from the community through senior living centers, churches, independent living residences, appropriate PD-related events, and the University of North Texas Health Science Center (UNTHSC) on-campus clinic between December 2016 and September 2019. Participants were recruited from these locations via flyers, University Daily News, and word of mouth, and screening for inclusion/exclusion criteria was conducted over the phone. Participants were included in the study if they were above the age of 18 years, otherwise healthy and injury-free outside of their PD diagnosis, abstained from any OMT or physical therapy (PT) within the past 30 days (self -reported), and were able to stand and walk independently without the use of assistive devices. Further, for those with PD, participants were included if they had a neurologist-diagnosed idiopathic PD in Hoehn and Yahr stages 1.0–3.0. Participants were excluded if they had cognitive impairment as defined by the Mini–Mental State Examination (<26 for PD and <24 for controls).

Study design and data collection

Data were collected utilizing an 18-camera Motion Analysis System (Motion Analysis Corp, Santa Rosa, CA) integrated with a dual-belt treadmill V-Gait Computed Assisted Rehabilitation Environment Network (CAREN, DIH Technology Inc., Norwell, MA) sampled at 120 Hz and 1200 Hz, respectively. A chest harness tethered overhead to a steel safety system could support the participant’s entire body weight in the event of a fall (Figure 1).

Figure 1:

Photo of a 63-year-old woman with PD in the motion capture system.

After consenting, participants drew a letter from a basket to identify randomization into one of three treatment groups (15 letters each). The study design included a sham, standardized OMT neck down (OMT-ND), and standardized OMT whole-body including OCMM (OMT-WB) protocols (Figure 2). After written informed consent was obtained, participants underwent a baseline assessment of clinical measures and neurological evaluations including the Mini–Mental State Exam, the UPDRS, and Hoehn and Yahr Stage (H&Y). Each participant’s natural walking speed was then calculated by timing a short walk over 20 feet overground distance and was utilized to set the initial treadmill speed. Participants then donned a harness, had 54 markers placed on key anatomical landmarks based on a modified Helen Hayes full-body marker set, and underwent a short static and dynamic calibration phase for the motion capture system before completing a variety of tasks. This study examined the walking task only. During the walking task, the treadmill was set at the participant’s natural walking speed and adjusted to match the participant’s comfortable habitual walking pace. Once adjusted, the participant walked for 30 s at this pace.

Figure 2:

Study design. PD, Parkinson’s disease; HC, healthy control; OMT-WB, osteopathic manipulative treatment whole-body protocol; OMT-ND, osteopathic manipulative treatment neck-down protocol.

After the baseline assessment, participants received an OMT or sham treatment protocol (Appendix A) from a board-certified neuromusculoskeletal medicine and osteopathic manipulative medicine (NMM/OMM) osteopathic physician (K.L.H. and R.S.). Following are brief descriptions of the OMT-ND, OMT-WB, and sham protocols.

1. OMT-ND: The neck-down protocol took into consideration previous relevant studies [14, 19]. OMT was utilized bilaterally on the following areas with one or more techniques including myofascial release, articulatory, muscle energy, and balanced ligamentous tension. The OMT-ND protocol lasted approximately 20–25 min and targeted the cervical, thoracic, and lumbar spine, shoulder girdle, sacroiliac joint, innominates, leg musculature (including psoas, piriformis, hamstring, and adductors), and ankles.

2. OMT-WB: This protocol included all of the techniques in the OMT-ND protocol, but it also included techniques focused on expected cranial dysfunction [16]. The OMT-WB protocol lasted approximately 25–30 min and included the following: evaluation for strain patterns, occipitoatlantal decompression, sphenobasilar synchondrosis decompression, occipitomastoid suture V-spread, temporal bone balancing, and venous sinus drainage techniques.

3. Sham: The sham protocol consisted of an examination of the subject’s active and passive ROM in the spine and extremities, and it tested the same joints that were treated with OMT. The subject was similarly positioned in sitting, supine, and lateral recumbent positions but did not receive active intervention. To provide a sham for the OMT-WB protocol, the subject lied supine with the physician’s pronated hands supporting the dorsal aspect of the patient’s head. The sham procedures were conducted for approximately 20–25 min.

Following receipt of an OMT or sham protocol, each participant underwent the same data collection procedures as outlined above.

Data processing

Visual3D (C-Motion, Germantown, MD) was utilized to create a virtual 3-dimensional (3D) model from the motion capture data. In Visual3D, a previously created model template containing pre-defined body segments and joints was applied to the position data of the reflective markers. This model is then applied to the walking trial of the participant so that joint angles can be calculated utilizing standard inverse dynamic calculations for each time point in the gait cycle.

MATLAB (Mathworks, Inc., Natick, MA) was utilized to time-normalize the resulting joint flexion angle data at the hip, knee, and ankle to 100% of the gait cycle including both the stance and swing phases. Heel strike was utilized for the delineation of gait cycles, which was defined based on the coordinate-based treadmill algorithm outlined by Zeni and colleagues [20].

The use of this coordinate-based treadmill algorithm for defining gait events eliminates the need for force plate data. Force plate data in studies involving individuals with gait abnormalities can be inaccurate, especially in cases in which a shuffling gait may result in insufficient vertical foot clearance during the swing phase, registering a ‘heel strike’ before the limb has finished its recovery.

Five gait cycles from the middle of the walking trial were extracted and averaged for each participant to overcome normal stride-to-stride variability [21]. The participant’s self-identified dominant limb, defined by which leg the participant would utilize to kick a ball, was utilized for the analysis because in individuals with PD who present asymmetrically, the dominant-side is found to be affected first in both right- and left-handed individuals [22]. ROM was calculated for each lower-limb joint as the maximum flexion of the joint subtracted by the maximum extension, or minimum flexion, during one full gait cycle and averaged for the five extracted gait cycles.

Statistical analysis

Demographic and clinical measures were analyzed between the three experimental groups (SHAM, OMT-WB, OMT-ND) utilizing one-way analysis of variance (ANOVA) and Hedge’s g effect size (Table 1). To examine the baseline differences in gait between PD and healthy control participants, statistical parametric mapping (SPM) independent t-tests [23] were performed on the pre-treatment (prior to receipt of OMT-WB, OMT-ND, or SHAM protocol) joint angle waveforms. To examine the effect of the OMT protocols on lower-limb joint motion, pre- and post-treatment ROMs were compared utilizing paired t-tests, and SPM paired t-tests were utilized to compare pre- and posttreatment gait cycle-normalized joint angle waveforms. Data was compared individually for PD and control experimental groups. To compare the effects of each treatment protocol SPM one-way ANOVAs were utilized to compare joint angle waveforms between treatment groups in both the pre- and post-treatment conditions. All statistical analysis was performed in MATLAB with a significance level set at p=0.05. Post-hoc analysis was performed with a Bonferonni correction.

SPM was chosen for this study because it allows for a continuous comparison of all data points in the gait cycle waveform The continuous nature of time series data presents a unique challenge for analysis and has traditionally been analyzed in a discrete manner in biomechanics by reducing the waveform to key events within the time series for direct comparison, but this can neglect most of the waveform and overlook significant differences found in portions of the gait cycle [24]. SPM considers the continuity of time series data and avoids data reduction and potential bias that can be introduced through discretization.

Limitations

This study had several limitations, the impact of which were mitigated through our research design. Standardized OMT protocols were utilized despite traditional osteopathic treatment principals, which champion a thorough evaluation and personalized treatment to address identified somatic dysfunction, limiting the application of our findings to a clinical setting. However, standardization of the OMT protocol is important because it allows for meaningful comparisons within the treatment groups and contributes to reproducibility of our results.

To allow for administration of the OMT protocol, the reflective markers were removed and re-applied for the posttreatment gait analysis. Our analysis relied on accurate marker placement on each subject before and after treatment, and to mitigate the risk associated with removal and reapplication of the markers, trained staff utilized key anatomical landmarks as marker placement references and the same staff member applied the markers pre- and posttreatment as suggested by prior studies [25]. Any deviation in the placement of the reflective markers on an individual before vs after treatment may have altered the results.

Unlike some other studies, we did not diagnose or record specific somatic dysfunctions. A chart on our protocol form (see Appendix) allowed for recording of the severity of somatic dysfunction in each region assessed.

Finally, this study examined the effects of a single session of OMT and OCMM on Parkinsonian gait. Future studies should be performed to determine if OMT may be helpful in the longitudinal treatment of PD patients’ gait mechanics. Although this certainly allowed for a larger sample size to be obtained, future studies should examine gait after several sessions to determine the effect of OMT and OCMM on the progression of motor and gait impairment in PD. Longitudinal studies will increase the relevance of the results for osteopathic physicians who manage PD over many visits.