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We report seven patients with cranial pachymeningitis of unknown origin in whom the main clinical features were headaches, ataxia, and cranial nerve palsies. CSF showed inflammatory changes. CT and MRI showed thickening of the falx and of the tentorium. The clinical course was chronic. Four patients improved with prednisolone but became steroid-dependent: in two cases, radiotherapy had no lasting improvement and in one, azathioprine permitted a reduction of the corticosteroids. Five patients had biopsy of the tentorium cerebelli or of the temporal dura mater. In two cases, autopsy revealed extensive pachymeningitis without parenchymal changes. In all instances, microscopic examination of the dura mater showed a cellular infiltrate of polymorphic cells; there were no epithelioid granulomas. Review of the literature discloses seven similar cases. We discuss the relationship of these lesions with inflammatory meningeal masses, the focal pachymeningitis of the Tolosa-Hunt syndrome, and multifocal fibrosis.

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To effectively prevent sport traumatic brain injury (TBI), means of protection need to be designed and tested in relation to the reality of head impact. This study quantifies head impacts during a typical snowboarding accident to evaluate helmet standards. A snowboarder numerical model was proposed, validated against experimental data, and used to quantify the influence of accident conditions (speed, snow stiffness, morphology, and position) on head impacts (locations, velocities, and accelerations) and injury risk during snowboarding backward falls. Three hundred twenty-four scenarios were simulated: 70% presented a high risk of mild TBI (head peak acceleration >80 g) and 15% presented a high risk of severe TBI (head injury criterion >1000). Snow stiffness, speed, and snowboarder morphology were the main factors influencing head impact metrics. Mean normal head impact speed (28 ± 6 km/h) was higher than equivalent impact speed used in American standard helmet test (ASTM F2040), and mean tangential impact speed, not included in standard tests, was 13.8 (±7 km/h). In 97% of simulated impacts, the peak head acceleration was below 300 g, which is the pass/fail criteria used in standard tests. Results suggest that initial speed, impacted surface, and pass/fail criteria used in helmet standard performance tests do not fully reflect magnitude and variability of snowboarding backward-fall impacts.