Author Archives: Dr David Shahar
Published in 1991, the Neck Disability Index (NDI) was the first instrument designed to assess self-rated disability in patients with neck pain. This article reviews the history of the NDI and the current state of the research into its psychometric properties—reliability, validity, and responsiveness—as well as its translations. Focused reviews are presented into its use in studies of the prognosis of whiplash-injured patients as well as its use in clinical trials of conservative therapies for neck pain.
Background: Published in 1991, the Neck Disability Index (NDI) was the first instrument designed to assess self-rated disability in patients with neck pain. This article reviews the history of the NDI and the current state of the research into its psychometric properties—reliability, validity, and responsiveness—as well as its translations. Focused reviews are presented into its use in studies of the prognosis of whiplash-injured patients as well as its use in clinical trials of conservative therapies for neck pain. Special Features: The NDI is a relatively short, paper-pencil instrument that is easy to apply in both clinical and research settings. It has strong psychometric characteristics and has proven to be highly responsive in clinical trials. As of late 2007, it has been used in approximately 300 publications; it has been translated into 22 languages, and it is endorsed for use by a number of clinical guidelines. Summary: The NDI is the most widely used and most strongly validated instrument for assessing self-rated disability in patients with neck pain. It has been used effectively in both clinical and research settings in the treatment of this very common problem. (J Manipulative Physiol Ther 2008;31:491-502) Key Indexing Terms: Neck Pain; Treatment Outcome; Reliability and Validity; Outcome Assessment (Health Care); Spine; Cervical Vertebrae. Vernon H. The Neck Disability Index: State-of-the-art, 1991-2008. Journal of Manipulative and Physiological Therapeutics. 2008 Sep;31(7):491-502. PubMed PMID: WOS:000259635600002.
SUMMARY: An often-suggested factor in the aetiology of craniomandibular disorders (CMD) is an anteroposition of the head. However, the results of clinical studies to the relationship between CMD and head posture are ontradictory. Therefore, the first aim of this study was to determine differences in head posture between well-defined CMD pain patients with or without a painful cervical spine disorder and healthy controls. The second aim was to determine differences in head posture between myogenous and arthrogenous CMD pain patients and controls. Two hundred and fifty persons entered the study. From each person, a standardized oral history was taken and blind physical examinations of the masticatory system and of the neck were performed. The participants were only included into one of the subgroups when the presence or absence of their symptoms was confirmed by the results of the physical examination. Head posture was quantified using lateral photographs and a lateral radiograph of the head and the cervical spine. After correction for age and gender effects, no difference in head posture was found between any of the patient and non-patient groups (P >0Æ27). Therefore, this study does not support the suggestion that painful craniomandibular disorders, with or without a painful cervical spine disorder, are related to head posture. KEYWORDS: craniomandibular disorders, cervical spine disorders, head posture, neck pain, temporomandibular disorders. Results No difference in head posture measured on the photographs with the participant in a sitting or a standing position was found (t ¼ 1Æ64, P ¼ 0Æ10). Therefore, the meanvalues of thetwophotographswereused in further analysis. A significant positive correlation was found between the head posture measured on the radiograph and on the photographs (R ¼ 0Æ43, P ¼ 0Æ00). In Table 2 the mean values and standard deviations of the two angles used to quantify head posture are shown for the non-patient group, the group with a painful CMD, the group with a painful CSD and the group with a painful CMD and CSD. For both methods, no difference was found in head posture between the groups (see Table 3). For the photographs, increasing age was associated with a more anteroposition of the head (t ¼ )2Æ39, P ¼ 0Æ02). No significant interactions between age and head posture were present. Table 4 shows the mean values and the standard deviations of the head posture for the non-CMD group, the group with a myogenous CMD, the group with an arthrogenous CMD and the group with a myogenous and an arthrogenous CMD. No ifference in head posture was found between the subgroups of CMD patients and the non-CMD patients and a positive age effect was present for the photographs (Table 5). No interactions were present. Visscher CM, De Boer W, Lobbezoo F, Habets L, Naeije M. Is there a relationship between head posture and craniomandibular pain? Journal of Oral Rehabilitation. 2002 Nov;29(11):1030-6. PubMed PMID: WOS:000179548100002.
The Relationship between Posture and Curvature of the Cervical Spine ABSTRACT Objective: To study the relationship between posture and curvature of the cervical spine in healthy subjects. Subjects: The study was composed of 54 healthy students (25 men and 29 women) aged 20-31 yr with a mean age of 24.7 yr. Methods: Lateral radiographs were taken of the head and cervical spine of the subjects while standing in a neutral position. Cervical spine posture was quantified by the angle of a reference line, composed of reference points of the upper six cervical vertebrae, with the horizontal axis. The curvature of the cervical spine was classified visually as lordotic, straight or reversed. Results: A relationship was found between posture and curvature of the cervical spine (p = .006); a more forward posture of the cervical spine was related to a partly reversed curvature; and a more upright posture was related to a 1ordotic curvature. Moreover, men more often exhibited a straight curvature, and women more often exhibited a partly reversed curvature. Conclusion: The curvature of the cervical spine is related to the subject's posture and gender. (J Manipulative Physiol Ther 1998; 21:388-91). Key Indexing Terms: Cervical Spine; Gender; Posture Visscher CM, de Boer W, Naeije M. The relationship between posture and curvature of the cervical spine. Journal of Manipulative and Physiological Therapeutics. 1998 Jul-Aug;21(6):388-91. PubMed PMID: WOS:000075676000002.
Postural control during quiet standing following cervical muscular fatigue: effects of changes in sensory inputs
Abstract The purpose of the present experiment was to investigate the effects of cervical muscular fatigue on postural control during quiet standing under different conditions of reliability and/or availability of somatosensory inputs from the plantar soles and the ankles and visual information. To this aim, 14 young healthy adults were asked to sway as little as possible in three sensory conditions (No vision, No vision-Foam support andVision) executed in two conditions of No fatigue and Fatigue of the scapula elevator muscles. Centre of foot pressure (CoP) displacements were recorded using a force platform. Results showed that (1) the cervical muscular fatigue yielded increased CoP displacements in the absence of vision, (2) this effect was more accentuated when somatosensation was degraded by standing on a foam surface and (3) the availability of vision allowed the individuals to suppress this destabilizing effect. On the whole, these findings not only stress the importance of intact cervical neuromuscular function on postural control during quiet standing, but also suggest a reweigthing of sensory cues in balance control following cervical muscular fatigue by increasing the reliance on the somatosensory inputs from the plantar soles and the ankles and visual information. Results of the present experiment showed that (1) the cervical muscular fatigue yielded increased CoP displacements in the absence of vision, (2) this effect was more accentuated when somatosensory information was disrupted by standing on a foam surface and (3) the availability of vision allowed the individuals to suppress this destabilising effect. On the whole, these findings not only stress the importance of intact cervical muscle function on postural control during quiet standing, but also suggest a reweigthing of sensory cues in balance control following to cervical muscular fatigue by increasing the reliance on the somatosensory inputs from the plantar soles and the ankles and visual information. Finally, we would like to mention that some subjects reported sensation of cervical pain at the end of the fatiguing exercise. Indeed, pain often develops following fatiguing muscle contractions. This sensation probably arises from firing of the groups III and IV afferents, that are sensitive to metabolites and inflammatory substances (e.g., potassium, lactic acid, bradykinin and arachidonic acid) accumulated within the muscle during activity to fatigue (e.g., ). There is thus a possibility that pain per se might affect postural control. Such a proposal is yet speculative and warrants additional investigations. Vuillerme N, Pinsault N, Vaillant J. Postural control during quiet standing following cervical muscular fatigue: effects of changes in sensory inputs. Neuroscience Letters. 2005 Apr 22;378(3):135-9. PubMed PMID: WOS:000228112600003.
Objective: While sensorimotor alterations have been observed in patients with neck pain, it is uncertain whether such changes distinguish whiplash-associated disorders from chronic neck pain without trauma. The aim of this study was to investigate head steadiness during isometric neck flexion in subjects with chronic whiplash-associated disorders (WAD), those with chronic non-traumatic neck pain and healthy subjects. Associations with fatigue and ef- fects of pain and dizziness were also investigated. Methods: Head steadiness in terms of head motion velocity was compared in subjects with whiplash (n = 59), non-traumatic neck pain (n = 57) and healthy controls (n = 57) during 2 40-s isometric neck flexion tests; a high load test and a low load test. Increased velocity was expected to reflect decreased head steadiness. Results: The whiplash group showed significantly decreased head steadiness in the low load task compared with the other 2 groups. The difference was explained largely by severe levels of neck pain and dizziness. No group differences in head steadiness were found in the high load task. Conclusion: Reduced head steadiness during an isometric holding test was observed in a group of patients with whip- lash-associated disorders. Decreased head steadiness was related to severe pain and dizziness. Key words: whiplash; isometric hold; head steadiness; neck pain; dizziness. J Rehabil Med 2010; 42: 35–41 Correspondence address: Astrid Woodhouse, Department of Public Health & General Practice, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), NO-7489 Trondheim, Norway. E-mail: astrid.woodhouse@ ntnu.no Submitted December 12, 2008; accepted October 7, 2009
Abstract Patients with whiplash associated disorders (WAD) have shown less accuracy in trajectory head motion compared to asymptomatic controls, which comply with clinical observations. The aim of this study was to investigate whether a trajectory head movement task can differ between WAD patients, chronic non-traumatic neck pain (CNP) patients and asymptomatic controls. Study groups included subjects with WAD (n = 35) with persistent neck pain after a car accident, CNP (n = 45), and asymptomatic controls (n = 48). Head motion was recorded from an unsupported standing position using a 3D Fastrak device. A laser pointer was attached to the head and by moving the head the subjects were asked to trace a figure of eight displayed on the wall at three different paces (slow, moderate and fast). The motion signal was decomposed into 1 Hz frequency bands and angular velocity (deg/s) within each frequency band was calculated. Significantly higher angular RMS velocity was found in the WAD group compared to the two other groups for the slow paced test (3–4 and 4–5 Hz frequency bands) and the moderate paced test (3–4 Hz frequency band) indicating irregular and uncoordinated movements. Angular RMS velocity was associated with pain and dizziness, but only with severe symptom levels. In conclusion, irregular head movements during a complex task were found in the WAD group, indicating altered central sensorimotor processing. The irregularities were found within frequency levels observable to clinicians. Conclusions In a trajectory movement task, a group of whiplash patients showed a consistent lack of movement smoothness when compared to CNP patients and asymptomatic controls. The movement irregularities were most evident in the 3–5 Hz frequency bands, and indicate that such irregularities may well be observable to clinicians when examining these patients. Astrid Woodhouse, Ottar Vasseljen, Øyvind Stavdahl Received: 11 August 2009 / Accepted: 23 September 2009 / Published online: 10 October 2009, Springer-Verlag 2009
Background: Persistent whiplash associated disorders (WAD) have been associated with alterations in kinesthetic sense and motor control. The evidence is however inconclusive, particularly for differences between WAD patients and patients with chronic non-traumatic neck pain. The aim of this study was to investigate motor control deficits in WAD compared to chronic non-traumatic neck pain and healthy controls in relation to cervical range of motion (ROM), conjunct motion, joint position error and ROM-variability. Methods: Participants (n = 173) were recruited to three groups: 59 patients with persistent WAD, 57 patients with chronic non-traumatic neck pain and 57 asymptomatic volunteers. A 3D motion tracking system (Fastrak) was used to record maximal range of motion in the three cardinal planes of the cervical spine (sagittal, frontal and horizontal), and concurrent motion in the two associated cardinal planes relative to each primary plane were used to express conjunct motion. Joint position error was registered as the difference in head positions before and after cervical rotations. Results: Reduced conjunct motion was found for WAD and chronic neck pain patients compared to asymptomatic subjects. This was most evident during cervical rotation. Reduced conjunct motion was not explained by current pain or by range of motion in the primary plane. Total conjunct motion during primary rotation was 13.9° (95% CI; 12.2–15.6) for the WAD group, 17.9° (95% CI; 16.1–19.6) for the chronic neck pain group and 25.9° (95% CI; 23.7–28.1) for the asymptomatic group. As expected, maximal cervical range of motion was significantly reduced among the WAD patients compared to both control groups. No group differences were found in maximal ROM-variability or joint position error. Conclusion: Altered movement patterns in the cervical spine were found for both pain groups, indicating changes in motor control strategies. The changes were not related to a history of neck trauma, nor to current pain, but more likely due to long-lasting pain. No group differences were found for kinaesthetic sense. Astrid Woodhouse* and Ottar Vasseljen Address: Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), N- 7489 Trondheim, Norway