Hamayun Zafar

Spatiotemporal consistency of human mandibular and head-neck movement trajectories during jaw opening-closing tasks

Previous studies of spatial and temporal coordination between human mandibular and head-neck movements during single as well as rhythmic jaw opening-closing tasks suggest that these movements are regulated by central nervous commands common for jaw and neck muscles. The present study evaluated the spatiotemporal consistency of concomitant mandibular and head-neck movements during repeated single jaw opening-closing tasks, in short- as well as long-term perspectives and at different speeds. The subjects were seated in an upright position without head support. They were instructed to perform single maximal jaw opening-closing movements, repeated ten times for fast and slow speed, respectively. Recordings were made at two sessions. A wireless optoelectronic technique was used to record three-dimensional mandibular and head-neck movements. The spatiotemporal consistency of repeated movement trajectories of the mandible (both in relation to the head and in space) and of the head-neck was quantitatively assessed by a spatiotemporal index (STI). In addition, mean movement trajectory patterns were compared for speed and recording sessions (expressed as correlation coefficient, r). The results showed relatively small STI (high degree of spatiotemporal consistency) and high r (reproducible trajectory patterns) values, both in short- and long-term perspectives, for concomitant mandibular and head-neck movements. The data were not generally speed related. In conclusion, the present results suggest a high degree of spatiotemporal consistency of the kinematic patterns of mandibular and head-neck movements during jaw opening-closing, in short- as well as long-term perspectives. They also indicate that underlying neural processes are invariant in nature. The results give further support to the notion of a tight functional coupling between the human jaw and the neck motor systems during natural jaw function.

Deep Brain Stimulation of Caudal Zona Incerta and Subthalamic Nucleus in Patients with Parkinson's Disease: Effects on Diadochokinetic Rate

The hypokinetic dysarthria observed in Parkinsons disease (PD) affects the range, speed, and accuracy of articulatory gestures in patients, reducing the perceived quality of speech acoustic output in continuous speech. Deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) and of the caudal zona incerta (cZi-DBS) are current surgical treatment options for PD. This study aimed at investigating the outcome of STN-DBS (7 patients) and cZi-DBS (7 patients) in two articulatory diadochokinesis tasks (AMR and SMR) using measurements of articulation rate and quality of the plosive consonants (using the percent measurable VOT metric). The results indicate that patients receiving STN-DBS increased in articulation rate in the Stim-ON condition in the AMR task only, with no effect on production quality. Patients receiving cZi-DBS decreased in articulation rate in the Stim-ON condition and further showed a reduction in production quality. The data therefore suggest that cZi-DBS is more detrimental for extended articulatory movements than STN-DBS.

Head Immobilization can Impair Jaw Function

Findings that jaw-opening/-closing relies on both mandibular and head movements suggest that jaw and neck muscles are jointly activated in jaw function. This study tested the hypothesis that rhythmic jaw activities involve an active repositioning of the head, and that head fixation can impair jaw function. Concomitant mandibular and head-neck movements were recorded during rhythmic jaw activities in 12 healthy adults, with and without fixation of the head. In four participants, the movement recording was combined with simultaneous registration of myoelectric activity in jaw and neck muscles. The results showed neck muscle activity during jaw opening with and without head fixation. Notably, head fixation led to reduced mandibular movements and shorter duration of jaw-opening/-closing cycles. The findings suggest recruitment of neck muscles in jaw activities, and that head fixation can impair jaw function. The results underline the jaw and neck neuromuscular relationship in jaw function.

Deep Brain Stimulation of Caudal Zona Incerta and Subthalamic Nucleus in Patients with Parkinson's Disease: Effects on Voice Intensity

Deep brain stimulation of the subthalamic nucleus (STN-DBS) in patients with Parkinsons disease (PD) affects speech inconsistently. Recently, stimulation of the caudal zona incerta (cZi-DBS) has shown superior motor outcomes for PD patients, but effects on speech have not been systematically investigated. The aim of this study was to compare the effects of cZi-DBS and STN-DBS on voice intensity in PD patients. Mean intensity during reading and intensity decay during rapid syllable repetition were measured for STN-DBS and cZi-DBS patients (eight patients per group), before- and 12 months after-surgery on- and off-stimulation. For mean intensity, there were small significant differences on- versus off-stimulation in each group: 74.2 (2.0) dB contra 72.1 (2.2) dB (P = .002) for STN-DBS, and 71.6 (4.1) dB contra 72.8 (3.4) dB (P = .03) for cZi-DBS, with significant interaction (P < .001). Intensity decay showed no significant changes. The subtle differences found for mean intensity suggest that STN-DBS and cZi-DBS may influence voice intensity differently.

Work-related musculoskeletal disorders among dental professionals in Saudi Arabia.

[Purpose] Musculoskeletal disorders are common causes of work-related disability in different professions involving the frequent practice of lifting, stooping, twisting, prolonged sitting, or standing. The dental profession is one such profession. Our aim was to determine the prevalence of work-related musculoskeletal disorders among dental professionals in Saudi Arabia, the factors associated with them, and their consequences and to propose preventive measures for them. [Subjects and Methods] A self-administered online questionnaire was sent to 225 members of the Saudi Dental Association. It included questions on demographic and professional characteristics, general medical history, and history of work-related musculoskeletal disorders before and after joining the dental profession. [Results] The questionnaire was completed by 65% of the respondents. Among them 85% reported that they had developed some pain due to work after joining the dental profession, and 42% reported that they were suffering pain at the time of the survey. Besides lower back, shoulder, and neck regions, the hands, upper back, and other regions like the elbows, buttocks, thighs, leg, and feet were areas in which they pain. [Conclusion] The prevalence of work-related musculoskeletal disorders among dental professionals in Saudi Arabia is high, affecting their daily activities, sometimes even forcing them to change their work setting. Age, gender, specialty of work, work setting, number of contact hours with patients, etc., were all found to be related to their work-related pain. We need to emphasize the role of ergonomics, counseling, proper techniques of patient handling, etc., during the training of dental professionals so that they can work efficiently.

Therapeutic Effects of Whole-Body Vibration Training in Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE To examine the current evidence regarding the effects of whole-body vibration (WBV) training in individuals with knee osteoarthritis (OA). DATA SOURCES We searched PubMed, CINAHL, Embase, Scopus, Physiotherapy Evidence Database (PEDro), and Science Citation Index for research articles published prior to January 2015 using the keywords whole body vibration, vibration training, and vibratory exercise in combination with the Medical Subject Heading osteoarthritis knee. STUDY SELECTION This meta-analysis was restricted to randomized controlled trials published in the English language. The quality of the selected studies was assessed by the PEDro Scale. The risk of bias was assessed using the Cochrane collaborations tool in the domain-based evaluation. We also evaluated the quality of each study based on the criteria given by the International Society of Musculoskeletal and Neuronal Interactions for reporting WBV intervention studies, consisting of 13 factors. DATA EXTRACTION Descriptive data regarding subjects, design, intervention, WBV parameters, outcomes, and conclusions were collected from each study by 2 independent evaluators. The mean and SD of the baseline and final endpoint scores for pain, stiffness, and function were extracted from the included studies. DATA SYNTHESIS A total of 83 studies were found in the search. Of these, 5 studies met the inclusion criteria and were further analyzed. Four of these 5 studies reached high methodologic quality on the PEDro Scale. Overall, studies demonstrated mixed results in favor of additive effects of WBV for reducing pain and improving function in knee OA. There was considerable variation in the parameters of the WBV included in this systematic review. CONCLUSIONS WBV training reduces pain and improves function in individuals with knee OA.

Coordinated Human Jaw and Head-Neck Movements During Natural Jaw Opening-Closing: Reproducible Movement Patterns Indicate Linked Motor Control

The complexity of the movements and muscle attachments between head, neck and mandible in man implies the existence of close functional relationships between the corresponding motor systems (see Figure 1A). Recent kinesiographic studies by our group have revealed concomitant head-neck movements during different voluntary jaw movement tasks (Nordh, Eriksson, Zafar & Al-Falahe, 1993). In the present report, we analyse the short and long term reproducibility of the temporal and spatial patterns of associated head-neck movements during voluntary jaw opening-closing tasks in human subjects.

Physical therapy education in Saudi Arabia.

[Purpose] To review the physical therapy educational program model, professional curriculum, and gender representation at major universities, as well as the quality and scope of physical therapy practice in Saudi Arabia. [Methods] Information regarding course curriculum, gender representation, and the quality and scope of physical therapy practice was collected from six universities in Saudi Arabia, the Saudi Physical Therapy Association, and the Saudi Health Commission. [Results] The first bachelor’s degree course of physical therapy was started in Saudi Arabia more than 30 years ago. In the last 10 years, the number of universities offering a bachelor’s degree in physical therapy has risen from 6 to 16, of which 14 are governmental and two are private. The 5- to 6 year bachelor’s degree program in physiotherapy includes an internship and preparatory prerequisite courses. Postgraduate study in physical therapy was introduced in 2000. Most universities offer segregated physical therapy courses for male and female students. [Conclusion] The enrollment of students in physical therapy programs in Saudi Arabia is gradually increasing. There are many opportunities to extend the scope of practice and contribute to the health needs of the Arab population and international communities.

Effect of chewing on postural stability during quiet standing in healthy young males

Abstract Background and aims: There is an important role of the neck sensory motor system in control of body posture and balance, and it is reasonable to believe that the jaw sensory motor system can directly and indirectly influence the modulation of the postural control system. The purpose of this study was to evaluate possible effects of dynamic jaw position while chewing on the postural control system. Materials and methods: We compared the mean center of gravity (COG) velocity during quite standing on a foam surface with eyes closed during three test conditions: (i) with resting jaw position, (ii) with open jaw position, and (iii) while chewing standard bolus of chewing gum. One hundred and sixteen normal healthy male subjects (average age 31.56 ± 8.51 years; height 170.86 ± 7.26 cm) were recruited for the study. Their COG velocity (deg/s) was measured using the NeuroCom® Balance Master Version 8.5.0 (Clackamas, OR, USA). Statistical analysis: Data was tested by the Friedman test. Results and conclusions. The results show that COG velocity decreased significantly while chewing in comparison to both open and resting jaw position (p < 0.0001). Our finding corroborates previous studies and suggests that the jaw sensory motor system can modulate postural control mechanisms. Gum chewing activity can enhance the postural stability during upright standing on an unstable surface and in the absence of visual input in healthy young adults. Our results should be taken into consideration in treatment and rehabilitation planning for patients with postural instability.

Perception about the importance and use of therapeutic massage as a treatment modality among physical therapists working in Saudi Arabia

[Purpose] To report perceptions about the importance and use of therapeutic massage as a treatment modality among physical therapists working in Saudi Arabia. [Subjects and Methods] A 21-item structured questionnaire was used to assess various domains including the demographic and professional characteristics of physical therapists and their perceptions about the importance and use of therapeutic massage in their daily practice. The questionnaire was uploaded online and the web link was sent to 140 members of the Saudi Physical Therapy Association (SPTA). [Results] The overall response rate was 86%. Among the respondents, 31% reported occasional use of therapeutic massage in their clinical practice, and 55% reported to have received formal training for therapeutic massage. Use of therapeutic massage was more common among female physical therapists. [Conclusion] Many physical therapists working in Saudi Arabia consider therapeutic massage to be an important treatment modality, but its use is relatively limited, either due to the time and effort required to dispense it, or the lack of scientific evidence for its efficacy.