Sensory Trick in Task Specific Upper Limb Dystonia (ULD)

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1 UNIVERSITÀ DEGLI STUDI DI CAGLIARI Dipartimento di Scienze Mediche e Sanità Pubblica Scuola di Specializzazione in Neurologia Direttore: Prof. Giovanni Defazio Sensory Trick in Task Specific Upper Limb Dystonia (ULD)

2 Dystonia Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. Dystonic movements are tipically patterned, twisting, and may be tremulous, initiated or worsened by voluntary action. Idiopathic dystonia (sporadic, familial) Secondary dystonia (inherited, perinatal\non-perinatal brain injury, cerebrovascular, drugs, infections, neoplastic, toxic, functional)

3 Idiopathic Dystonia Idiopathic dystonia mainly includes: early-onset dystonia Age at onset 20 years old. Often will progress to generalized dystonia. late-onset dystonia Age at onset > 20 years old. Tends to remain focal or segmental.

4 Late-onset dystonia blepharospasm Oromandibular dystonia Cervical dystonia Lower limb dystonia Upper limb dystonia

5 Epidemiological and clinical features about the most common forms of late-onset idiopathic dystonia Blepharospasm Laryngeal Dystonia Cervical Dystonia Hand Dystonia Prevalence (cases per million) Sex prevalence Women Women Women Men Mean age (years) at onset (95% CI) 55.7 (55-56) 43 (42-44) 40.7 (40-41) 30 (37-40) % of dystonia spread within the first 5 years of history 58% 9-19% 12-35% 13% Task-specificity No Yes No Yes

6 Sensory trick Sensory trick (ST), also called geste antagoniste (GA), is a specific maneuver that temporarily improves dystonia. Typically, ST includes several maneuvers that may vary from person-to-person, and with dystonia localization. Some individuals may also manifest multiple tricks.

7 The Geste Antagoniste includes the following stimuli: Tactile and Proprioceptive Visual and Auditory Thermal Imaginary Tricks

8 Reported prevalence for effective ST in different focal dystonias Type of focal dystonia Frequency % of effective GA Blepharospasm % Oromandibular dystonia % Cervical dystonia 81 89,6 % Writer s Cramp 20 % Musician s dystonia 19 %

9 The variable frequency of ST in different focal dystonias may reflect different pathophysiological mechanisms. Alternatively, it is also possible that patients with CD or BSP may merely have a greater ease to spontaneously self-discover ST than patients with ULD.

10 Aims of the study To see whether instructing a group of patients with ULD and disturbed handwriting to apply a standardized trick maneuver would increase the frequency of effective ST in the study population. To see whether performing the standardized trick could aid in distinguishing ULD patients with dystonic tremor from non dystonic patients with upper limb action tremor.

11 The study sample included 37 patients (all of them were righthanded) with ULD and disturbed handwritng who were asked to write a standard sentence: «Oggi è una bella giornata di sole»

12 Metodi 2 (GA) foto

13 Aim 1 Five out of 37 patients (13%) reported to have experienced a spontaneous ST over their disease history Performing the standardized trick maneuver improved handwriting in 14/37 patients (38%).

14 Results Handwring test with effective sensory trick

15 Results Handwriting test with ineffective sensory trick

16 Results ST + (n. 14) ST (n. 23) Sex 9 men 5 women 9 men 14 women Mean age (years) + SD Mean age at dystonia onset (years) + SD Mean dystonia duration (years) N. of patients with focal dystonia (%) N.S. N.S. (18.1 years, SD 10.1) (18.1 years, SD 10.1)

17 Aim 2 Variable Dystonic patients with tremor (n. 19) Non-dystonic patients with tremor (n. 20) P Sex (n. of men) N.S. Mean age (years) + SD N.S. Mean age at dystonia onset (years) + SD Mean dystonia duration (years) + SD N. of patients with focal dystonia (%) n. of patients with effective geste antagoniste (%) N.S N.S. 10 / N.S. 8 (42%) 1 (5%) 0.02 Non-dystonic patients with tremor included 10 patients with essential tremor, 9 patients with parkinsonism, and 1 patient with functional tremor. In the latter patient, tremor disappeared after distracting maneuvres like opening/closing the non-tremulous hand and writing a number on the forehead.

18 Conclusions The variable frequency of spontaneous, selfdiscovered ST observed in patients with CD, BSP, and ULD probably does not reflect differences in pathophysiological mechanisms but possibly the variable ease/difficulty of patients with different forms of focal dystonia to self-discover ST. When ST is present, it helpfully distinguished dystonic and non dystonic tremor (sensitivity 89%, specificity 95%) Functional (psychogenic) tremor may however represent a confounding factor.