Poster Abstracts Wednesday, November 9, 2005 $321

Methods: ET patients with at least a --2 UL action/postural tremor were recruited. The dominant UL was rated at baseline using the WHIGET tremor scale, Purdue pegboard, Jebsen hand tests, and handwriting scale (0-4). Each subject was randomly assigned to either room or cold temperature (15°C), then retested q30 minutes × 120 minutes. The second treatment involved UL inmlersion in the other temperature. Rater was blinded. Results: Forty-one ET patients (20 men; 21 women; ages 34-86) completed the study. The average WHIGET score remained signifi- cantly improved only at 0, 30 & 60 minutes post-cold immersion. All WHIGET subtest score means were significantly better at 0 minute post-cold immersion, but at 60 minutes, only pouring & finger-to-nose scores were improved. The mean handwriting score was improved only at 0 & 30 minutes post-cold immersion. No statistical difference was noted in the Purdue pegboard scores at any point. Jebsen hand subtests of card turning and feeding showed improvement at 30 minutes post- cold inm~ersion. Conclusion: Upper limb cold immersion improves hand tremor and hand function in ET patients for about 60 minutes post-immersion. Limb cooling may be a practical nonpharmacologic alternative for ET patients requiring some improvement of tremor for a short period.

0867 Saccadic trajecto~cy in Huntington's disease

Fielding, j~,2, Georgiou-Karistianis, N ~, Millist, L z, Churchyard, A 3, White, O ~. 1Monash University, Melbourne, Australia.." ~Mental Health Research Institute, Melbourne, Australia; 3Movement Disorders Laboratory, Kingston Centre, Melbourne, Australia

Background: The trajectories of saccadic eye movements can be modulated by the presence of a competing visual distractor. It has been proposed that the superior colliculus (SQ controls the initial deviation through competitive lateral interactions. Given the ramifications of connections between basal ganglia (BG) thalamo-cortical circuitry and the SC, it was anticipated that tiffs modulation would be differentially effected in patients with Huntington's disease, which in its early stages is primarily a disorder of the BG. Method: Horizontal deviation was determined for both exogenously driven and endogenously driven vertical saccades in the presence of peripheral distractors. Results: For control subjects, the irdtial trajectories of both exogenous and endogenous vertical saccades curved away from distractor loca- tions, as predicted. However, for HD patients, the presence of a distractor, irrespective of its spatial location, resulted in a consistent directional bias relative to baseline natural curvature. A strong leftward bias was demonstrated for exogenously generated saccades, particularly those directed downwards, and for endogenously generated saccades, a strong rightward bias, once again particularly for those directed downwards. Also, saccadic latencies revealed no effect of spatial compatibility, unlike control subjects whose responses were faster where distractor and target stimuli appeared in the same hemifield, for either type of saccade. Results demonstrate perseverative behaviour, a cardinal feature of HD, and aberrant modulation of activity over saccade 'motor maps'. Conclusion: The presence of distractor stimuli seemingly resulted in reversing the natural trajectory of saccades, triggering unrelated or poorly focused inhibitory behaviour for the horizontal component of saccade progranmffng.

0868 Mimicked tremor in normal s~bjects: the effect of distraction

Geevasinga N l, Mahant N ~, Morris JGL 2, Fung VSC. ~. 1University of Sydney, Sydney, Australia.." ~Departtnent of Neurology, Westrnead Hospital, Sydney, Australia

It has been proposed that one subtype of psychogenic tremor is gene- rated through voluntary shaking. A commonly used diagnostic sign

is to demonstrate that distracting manoeuvres, such as tapping with the other hand at frequencies determined by the examiner, disrupt the tremor. The aim of this study was to quantify the effects of varying the frequency of mimicked tremor on patterns of muscle bursting and degree of distractibility in normal subjects performing voluntary shaking.

Subjects were asked to mimic tremor of varying frequencies across one or two joints (wrist . . elbow . . shoulder). Comparisons were made between unilateral versus bilateral tremor and unilateral tremor with or without motor distraction. Surface EMG was recorded over wrist and elbow flexors and extensors, and accelerometers were placed on the dorsum of the palm and wrist. Seven subjects were studied, three with intermediate musical skills.

As the frequency of mimicked tremor progressed from low (r~l Hz) frequencies to lffgher frequencies (~3-5 Hz) bursting in antagonist pairs changed from a variable relationship to becoming exclusively alternating in pattern. When tapping with the contralateral hand to a metronome frequency of 0.6 Hz, two subjects were able to maintain a non-distractible tremor at all frequencies, while at a metronome frequency of 1.8 Hz three subjects were able to maintain a non- distractible tremor; two of these subjects were musicians. EMG activity was coherent within and across limbs.

Absence of distractibility does not reliably distinguish involuntary from voluntary tremor. Voluntary tremor at higher frequencies is associated with an alternating pattern of muscle bursting.

0869 Clinical protlle of Cranial dyslonia in Indian patients

Goyal, C, Behari, M. AII~fS, New Delhi, India

Aims & Objectives: To Study the demographic, clinical and epidemio- logical factors in cranial dystonias in Indian patients. Materials & Methods: Patients with cranial dystonia including blepharospasm (BS), oromandibular dystorda (OMD) and Meige's syndrome attending movement disorders clinic of AIIMS, New Delhi, were enrolled. Demographic. features, age of onset, precipitating and relieving factors, etc were studied. Both old and new cases were taken. Severity of disease was assessed on the scale of 0-4. Results: Total 295 patients of dystonia were scrutinized and 108 cases of crmffal dystonia were enrolled during 3-year study period. There were 55 cases of BS, 19 cases of OMD and 34 cases of Meige's syndrome. Mean age was 53.25 ± 11.29 (range 12-73) years. All patients were right handed. Male constitute 65% of total cranial dystonia patients and 13% patients with cranial dystonia had family history of extra- pyramidal syndromes including dystonia. Mean age of onset was 49.4 ± 11.72 years and duration of illness was 46.75 ± 69.59 months (range 2-516 months). Mean severity of dystorda was 3.7 ± 0.74. Irdtial symptoms , previous medications, lffstory of trauma, morning benefit, gest antagonistique, associated emotional factors, various precipitating, relieving factors and associated other dystonias were evaluated. Conclusion: Blepharospasm and Meige's syndrome are common crmffal dystonia in Indian patients. Most of the cases (48%) presented very late (after 4 years of illness).

0870 Treahnent of higher level Gait dis~turbances with Rivastigmine: a pilot study

Gutevich, T 1'2, Merims, D 1"2, Herman, T 1, Hausdorft, JM 1"2, Giladi, N 1"2. ZMovement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center; 2Suckler School of Medicine, Te[-Aviv University

Background: Higher level gait disturbances (HLGD) are characterized by the combination of postural instability and exaggerated fear of falling. We propose that cognitive dysfunction may play a role in the development of HLGD.