Incidence and predictors of chronic headache attributed to whiplash injury.

We identified clinical, demographic and psychological predictive factors that may contribute to the development of chronic headache associated with mild to moderate whiplash injury [Quebec Task Force (QTF) ≤ II] and determined the incidence of this chronic pain state. Patients were recruited prospectively from six participating accident and emergency departments. While 4.6% of patients developed chronic headache attributed to whiplash injury according to the International Classification of Headache Disorders, 2nd edn criteria, 15.2% of patients complained about headache lasting > 42 days (QTF criteria). Predictive factors were pre-existing facial pain [odds ratio (OR) 9.7, 95% confidence interval (CI) 2.1, 10.4; P = 0.017], lack of confidence to recover completely (OR 5.5, 95% CI 2.0, 13.2; P = 0.005), sore throat (OR 5.0, 95% CI 1.5, 8.9; P = 0.013), medication overuse (OR 4.2, 95% CI 1.4, 12.3; P = 0.009), high Neck Disability Index (OR 4.0, 95% CI 1.3, 12.6; P = 0.019), hopelessness/anxiety (OR 3.8, 95% CI 1.3, 8.7; P = 0.024), and depression (OR 3.3, 95% CI 1.2, 9.4; P = 0.024). The lack of a control group limits the conclusions that can be drawn from this study. Identified predictors closely resemble those found in chronic primary headache disorders.

Gray matter changes related to chronic posttraumatic headache.

BACKGROUND: Although up to 15% of patients with whiplash injury develop chronic headache, the basis and mechanisms of this posttraumatic headache are not well understood. METHODS: Thirty-two patients with posttraumatic headache following whiplash injury were investigated within 14 days after the accident and again after 3 months using magnetic resonance-based voxel-based morphometry. Twelve patients developed chronic headache lasting longer than 3 months and were studied a third time after 1 year. RESULTS: Patients who developed chronic headache revealed decreases in gray matter in the anterior cingulate and dorsolateral prefrontal cortex after 3 months. These changes resolved after 1 year, in parallel to the cessation of headache. The same patients who developed chronic headache showed an increase of gray matter in antinociceptive brainstem centers, thalamus, and cerebellum 1 year after the accident. CONCLUSION: We demonstrate adaptive gray matter changes of pain processing structures in patients with chronic posttraumatic headache in regard to neuronal plasticity, thus providing a biologically plausible basis for this common, disabling problem.

Workspace zone differentiation and visualization for virtual humans.

Human performance measures such as discomfort and joint displacement play an important role in product design. The virtual human Santos, a new generation of virtual humans developed at the University of Iowa, goes directly to the computer-aided design model to evaluate a design, saving time and money. This paper presents an optimization-based workspace zone differentiation and visualization. Around the workspace of virtual humans, a volume is discretized to small zones and the posture prediction on each central point of the zone will determine whether the points are outside the workspace as well as the values of different objective functions. Visualization of zone differentiation is accomplished by showing different colours based on values of human performance measures on points that are located inside the workspace. The proposed method can subsequently help ergonomic design. For example, in a vehicle's interior, the controls should not only lie inside the workspace, but also in the zone that encloses the most comfortable points. Using the palette of colours inside the workspace as a visual guide, a designer can obtain a reading of the discomfort level of product users.

Prospective PC-interactive pressure algesimetry of post-traumatic neck pain after whiplash injury.

Cervical pain is a prominent symptom in both acute whiplash injury and late whiplash syndrome. However, no systematic analysis of post-traumatic pain development covering several weeks has yet been performed in whiplash patients. It was the aim of the present study to analyse the duration and course of post-traumatic muscle pain due to whiplash injury in a prospective follow-up examination with short investigation intervals. A recovery of initially increased muscle pain after whiplash injury within 1 month was hypothesized. Pressure pain of the splenius and trapezius muscles was recorded using PC-interactive pressure algesimetry. Whiplash patients were investigated during the acute injury stage and after 3, 4, and 6 weeks and compared with matched controls. We found significantly increased pressure pain of the splenius and trapezius muscles in the acute stage of whiplash injury. After 4 weeks patients' scores of pain parameters were comparable to those of healthy control subjects. Within the patient group the first changes of pressure pain were observed within 3 (splenius) and 4 weeks (trapezius). For most patients the recovery dynamics lasted 4-6 weeks. A minority of patients did not show any improvement after 6 weeks. The present study shows that the dynamics of pressure pain due to whiplash injury can be quantified by means of PC-interactive pressure algesimetry. Our results confirm the clinical experience that the acute post-traumatic cervical syndrome normally subsides within weeks.

Quantification of acute neck pain following whiplash injury by computer-aided pressure algesimetry.

Until now the clinical investigation of cervical pain due to whiplash injury is mainly based on finger palpation. The present study introduces a PC-interactive pressure algesimetry to standardize cervical pain measurement. Pressure pain scores of the splenius and trapezius muscles of 23 patients with an acute cervical syndrome after whiplash injury were compared to those of 24 healthy subjects. The pressure painfulness of neck and shoulder muscles was significantly increased in whiplash patients. The splenii muscles showed an equally increased muscle pain whereas the trapezii muscles showed a left-sided preponderance of painfulness, possibly due to the seat belt position in this group of motor vehicle drivers. The computer-interactive pressure algesimetry enables a standardized and rater-independent quantification of the cervical syndrome with neck and shoulder pain caused by whiplash injury.

Conformational studies on host-guest peptides containing chiral alpha-methyl-alpha-amino acids. Comparison of the helix-inducing potential of alpha-aminoisobutyric acid, (S)-2-ethylalanine and (S)-2-methylserine.

The conformational behaviour of host-guest peptides of the type Ac-Ala-Xxx-Ala-Ala-Xxx-Ala-Ala-Xxx-Ala-Ala-NH-PEGM (Xxx = alpha-aminoisobutyric acid (Aib), (S)-2-ethylalanine ((S)-Iva), (S)-2-methylserine ((S)-alpha-MeSer)) has been studied by CD spectroscopy in CF3CH2OH, CH3OH, and water and by i.r. spectroscopy in CHCl3 and in the solid state. In this way the relative helix-inducing potential of the two chiral alpha-methyl-alpha-amino acids (S)-Iva and (S)-alpha-MeSer could be established in comparison to the strong helix-former Aib. The results show that (S)-Iva exerts a comparable helix-inducing effect as Aib, making this amino acid a valuable complementary tool for the stabilization or induction of helices. No significant helix-promoting effect was observed for (S)-alpha-MeSer in polar solvents; however, the i.r.-spectroscopic data in CHCl3 and in the solid state point to a helical conformation under these conditions. Possible reasons for the different behaviour of (S)-Iva and (S)-alpha-MeSer are briefly discussed.