Although many patients with multiple sclerosis (MS) complain of trigeminal neuralgia (TN), its cause and mechanisms are still debatable. In a multicentre controlled study, we collected 130 patients with MS: 50 patients with TN, 30 patients with trigeminal sensory disturbances other than TN (ongoing pain, dysaesthesia, or hypoesthesia), and 50 control patients. All patients underwent pain assessment, trigeminal reflex testing, and dedicated MRI scans. The MRI scans were imported and normalised into a voxel-based, 3D brainstem model that allows spatial statistical analysis. The onset ages of MS and trigeminal symptoms were significantly older in the TN group. The frequency histogram of onset age for the TN group showed that many patients fell in the age range of classic TN. Most patients in TN and non-TN groups had abnormal trigeminal reflexes. In the TN group, 3D brainstem analysis showed an area of strong probability of lesion (P<0.0001) centred on the intrapontine trigeminal primary afferents. In the non-TN group, brainstem lesions were more scattered, with the highest probability for lesions (P<0.001) in a region involving the subnucleus oralis of the spinal trigeminal complex. We conclude that the most likely cause of MS-related TN is a pontine plaque damaging the primary afferents. Nevertheless, in some patients a neurovascular contact may act as a concurring mechanism. The other sensory disturbances, including ongoing pain and dysaesthesia, may arise from damage to the second-order neurons in the spinal trigeminal complex.

In this clinical and neurophysiological study, we examined the clinical characteristics and underlying mechanisms of neuropathic pain related to multiple sclerosis. A total of 302 consecutive patients with multiple sclerosis were screened for neuropathic pain by clinical examination and the DN4 tool. In patients selected for having ongoing extremity pain or Lhermitte's phenomenon, we recorded somatosensory evoked potentials, mediated by Aβ non-nociceptive fibres, and laser evoked potentials, mediated by Aδ nociceptive fibres. Of the 302 patients, 92 had pain (30%), and 42 (14%) neuropathic pain. Patients with neuropathic pain had more severe multiple sclerosis, as assessed by the expanded disability severity score, than those without pain. Whereas, in patients with ongoing neuropathic pain, laser evoked potentials were more frequently abnormal than somatosensory evoked potentials, we found the opposite in patients with Lhermitte's phenomenon. Our data underline the clinical importance of pain in multiple sclerosis and indicate that a more severe disease is associated with a higher risk of developing neuropathic pain. The prevalence of pain that we found, which was lower than that reported in previous studies, may reflect the lesser disease severity in our patients. Neurophysiological data show that whereas ongoing extremity pain is associated with spinothalamic pathway damage, Lhermitte's phenomenon is related to damage of non-nociceptive pathways. These findings may be useful in designing a new therapeutic approach to neuropathic pain related to multiple sclerosis.

In the last two years, the environmental theory on the aetiology of Parkinson disease has acquired new data. From an experimental point of view, a new model of parkinsonism induced by rotenone, a diffuse insecticide, has been proposed, and in vitro studies have provided proof that several pesticides stimulate the formation of alpha-synuclein fibrils (one of the principal constituents of Lewy bodies). Moreover, a meta-analysis of all case-control studies so far performed showed a positive, statistically significant association between pesticide exposure and PD. In this context, we are performing a cohort study on 5575 licensed pesticide users in the province of Viterbo. After 27 years of follow-up, 4788 subjects are still alive. The aim of this study is to measure the prevalence of Parkinson's disease in a large group of workers with theoretically increased risk.

It emerges from this study that duloxetine might become an effective therapeutic alternative to be investigated in a larger number of MS patients for the treatment of OAB. Duloxetine should be considered a first-choice drug in the treatment of MS patients presenting both depression and OAB; in addition, it should also be considered as a suitable alternative or as concomitant treatment in MS patients with OAB but not experiencing depression.

The results confirm that MS occurs more frequently in central Italy than might be expected on the basis of the geographic-related distribution model, thus supporting the view that this is a high-risk area for the disease.