$326 Wednesday, November 9, 2005 Poster Abstracts

Background: In median nerve somatosensory evoked cortical poten- tials, an enhanced N35 is sometimes seen; we sought to define its clinical associations. Methods: 600 consecutive patient median nerve SEPs were retro- spectively analysed and compared with 27 controls. An enhanced N35 feature (C3~/C4 ~ referred to Fz) was deemed present when N35 amplitude exceeded that o f the preceding P25 deflection. Further comparison was made of characteristics o f 72 patients each, with and without the feature, with normal earlier SEP components. Results: The enhanced N35 feature was more prevalent in patients than controls (23.2"/0 vs 7.4% of individuals, 17.6"/o vs 5.6% of nerves; Fisher's exact p - 0.06 and 0.02 respectively). A strong association existed in patients manifesting dystonia alone compared to other patients (5.8% with vs 1.1% without; RR 2.8; Fisher's p -- 0.003), as well as compared to controls (OR 20; p < 0.001). Myoclonus alone, compared with other patients (13.7% with vs 6.3% without; RR 1.8; p - 0.02) and with controls (OR 7.8; p - 0.006). There was no clear relationship with large fibre sensory abnormalities and suspected or definite MS was also not significantly different from controls. These relationships held true in the comparison of two patient groups without SEP abnornhalities. The sensitivity and specificity were 65"/o and 78% for dystonia; 43"/o and 79% for myoclonus. Conclusion: The association of tiffs feature with some myoclonic conditions is known ("giant" SEP). However, its occurrence in dystonia may be a useful new finding in an established test, helping to identify a condition where there is increasing evidence for disordered sensorimotor integration.

0886B N35:P25 SEP Amplitude Ratio in Dys~tonic Patients: Evidence for Disordered Sensory Processing Without Clinical Sensory Deficits?

Ng K 1, Jones SJ i'2. 1Th e National Hospital for Neurology and Neurosurgery, University College London, London, United Kingdom; 2Institute of Neurology, University College London, London, United Kingdom

Backgrouml: Our previous investigation with median nerve SEPs demonstrated an association of the enhanced N35 with dystonia and myoclonus. We aimed to support tiffs finding by comparing N35:P25 amplitude ratio in subjects with these disorders to controls, and to define clinical features in common. Methods: 39 patients with myoclonus, 13 with dystonia and 6 with features of both were compared to 27 healthy controls. None had evidence of large fibre sensory dysfunction and none had "giant" SEPs (P25 amplitude > 13uV). Cortical derivations were C3'/C4' referred to Fz with amplitudes measured from the preceding peak of opposite polarity. Patient characteristics were studied from detailed medical records. Results: N20 and N35 absolute latencies and its standard deviation in patients were highly comparable to controls. Ratios were signifi- cantly lffgher for patients with any dystonia (R median 0.86 vs 0.54, p -- 0.003; L median 0.82 vs 0.59, p -- 0.004; Mann-Whitney), and maintained significance for patients with dystonia alone (R median 0.88, p -- 0.01; L median 0.85, p -- 0.009). The ratio was not signifi- cantly enhanced in patients with myoclonus alone. Dystonia aetiology was varied including genetic and secondary causes. No patient had sensory symptoms or signs. Conclusion: These results accord with our previous findings. It strengthens the association with dystonia, and confirms that not all aetiologies for myoclonus are associated with giant SEPs or an enhanced N35:P25 ratio. It provides some validation for the use of the enhanced N35 feature (N35 > P25) in dystonia and raises interesting questions regarding the separate sensory inputs for basal ganglia and lemniscal systems in dystonia.

0887 Botulinum toxin increases quality of life in blephaxospasm

S. Ochudlo 1, G. Opala 1, P. Brylffarski i . 1Medical University of Silesia, ~V_atowice, Poland

Background: Blepharospasm (B) is a focal dystonia, and the main point of it is hyperactivity of musculi orbicularis oculi which leads to sight dysfunctions. Patients with B usually experience decreased quality of life. Aim: The aim of tlffs study was to assess the impact of BTX on quality of life in patients with B. Methods: 33 patients (18 men and 25 women) with B were analyzed. Mean age of patients was 62,4 years (32-86). Mean age when the disease was diagnosed was 55,2 years (126-80). Mean duration of disease was 7 years (11-14). Two different types of BTX were applied: Botox and Dysport. The average single dose of Botox was 47,6 u. (25-50) and 223,07 u. of Dysport. The therapeutic effect was noticed after 7,69 days (11-45) and it lasted on average for 12 weeks (11-48). Mean time of treatment was 3 years (0,5-12). SF-36 was used to assess the impact of BTX on quality of life in patients with B; before and 4 weeks after injection. Physical function increased by 24,3%, role physical by 84,7"/0, role emotional by 102,4"/o, social functioning by 43,1%, mental health by 34,3"/0, vitality by 42%, general health by 24,77"/0. There was no sigtffficant effect in bodily pain. Conclusions: Local applying of BTX increases quality of life in patients with B.

0888 Encephalitis Lethargiea like syndrome: A reenlerging parkinsonis~n

Phanthumchinda, K, Sridam, N, LikJtjaroen, Y. Chulalangkarn University

Sporadic cases of Encephalitis Lethargica-like syndrome (EL) are increasingly reported. Apart from parkinsordsm and other features, MRI changes in midbrain, basal ganglion and temporal lobes as well as detection of CSF oligoclonal band become important clues to diagnosis. First two Thai cases of EL were documented. Case L A 17 year-old man presented with subacute somnolence and external ophthalmoplegia. The syndrome was gradually improved after dexamethasone and intravenous inmmnoglobulin. Two months later, he was alert and mild ophthalmoparesis was detected. Parkinsordsm characterised by severe resting tremor of upper extremities and head, mild bradykinesia, generalized cogwheel rigidity as well as hyperorality and hypersexuality were observed. Case II. A 71 year-old man developed progressive resting tremor of upper extremities, head and jaw with mild bradykinesia and general- ized cogwheel rigidity witlffn three months. He was disoriented and had poor recent memory. Both cases had no definite antecedent infection. Investigations in both cases revealed: 1.) T2 and FLAIR hypersignal intensity on MRI in midbrain tegmentum, substantia nigra, bilateral syJm~letrical basal ganglia and temporal lobes. 2.) positive CSF oligoclonal band 3.) normal CSF profiles 4.) negative CSF viral studies 5.) negative serology for HIV, syplfflis and streptococcal infection 6.) negative systemic autoimmune profiles 7.) no evidence of other basal ganglia diseases. Both cases responded partially to levodopa. Conclusions: EL is still prevalent. According to recent data, EL was not invasive influenza encephalitis and may be an inmmne-mediated movement disorders. MRI and oligoclinal band are helpful diagnostic tests. EL should be considered in the differential diagnosis of recent onset parkinsonism with neuropsychiatric disorders.

0889 Deep Brain Slhnulation Of The Cenlromedian Nucleus For The T~eahnent Of Tourette Syndrome: A Case Report