LIMB DYSTONIA HISTORY, PHENOMENOLOGY, EVALUATION, TREATMENT Mark F. Lew, MD Professor of Neurology Vice-chair Department of Neurology Vandermeulen Chair in PD Research Director Division of Movement Disorders KECK/USC School of Medicine Los Angeles, CA
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LIMB DYSTONIA HISTORY,
PHENOMENOLOGY,
EVALUATION, TREATMENT
Mark F. Lew, MDProfessor of Neurology Vice-chair Department of Neurology
Speaker’s Bureau participant: Acadia Pharmaceuticals, Inc., Impax Laboratories, Inc., Lundbeck, TevaPharmaceuticals, UCB, and US WorldMeds LLC.
Research funding; the Parkinson’s Study Group, Michael J. Fox Foundation, Civitas Therapeutics, Inc., BiotieTherapies, Cynapsus Therapeutics, Inc., IntecPharma, Neuroderm, and the National Institutes of Health.
LIMB DYSTONIA
GENERAL DEFINITION
DYSTONIA IS CHARACTERIZED BY SUSTAINED MUSCLE CONTRACTIONS FREQUENTLY CAUSING REPETITIVE TWISTING MOVEMENTS OR ABNORMAL POSTURES
PREVALENCE ESTIMATES OF DYSTONIA VARY: 2.7/1,000,000 ROCHESTER MINNESOTA
11.1/100,000 ASHKENAZI JEWISH NYC
60/100,000 LATE ONSET NEW ENGLAND
300/100,000 LATE ONSET ITALY >50yo
Defazio G, et al. The Lancet Neurology. 2004; 3(11): 673-678.
DYSTONIA BY TOPOGRAPHY
Tarsy D, et al. N Engl J Med. 2006; 355:818-829.
FOCAL DYSTONIA: AGE OF ONSET
DYT-111.3 yrs
WC38.4
CD40.8
SD43.0
Bleph-oromand55.7
O’Riordan S, et al. Neurology 2004;63:1423-1426.
FOCAL DYSTONIAS
Tarsy D, et al. N Engl J Med. 2006; 355:818-829.
.
Tarsy D, et al. N Engl J Med. 2006;
355:818-829.
LIMB DYSTONIA:PHENOMENOLOGY
MOST COMMON FORM IS WRITER’S CRAMP
INVOLUNTARY HAND POSTURES IMPAIR WRITING
UNDERESTIMATED AS PATIENTS DON’T SEEK
MEDICAL ADVICE
MALE PREDOMINANCE
CASE PRESENTATION
53 Y/O RH FEMALE WITH 3 YRS OF PROG
DIFF WRITING
NO DIFFICULTY USING HER HANDS FOR
OTHER TASKS
NO CRAMPING, SPASM, OR INVOLUNTARY
MVMT ELSEWHERE
WRITERS CRAMP VIDEO
TREATMENT
ONABOTULINUM TOXIN INJECTED AS
FOLLOWS WITH EMG GUIDANCE:
– 5 U R EXT INDICES PROPRIUS
– 5 U R EXT DIGITORUM COMMUNIS (FASCICLE
FOR MIDDLE FINGER)
EXTENSOR INDICES PROPRIUS (9)
EXTENSOR DIGITORUM COMMUNIS (7)
Perotto A. Anatomical Guide For The Electromyographer. 1994: p42-45.
Mcminn RMH, et al. Color atlas of human anatomy. 1977: p127.
LIMB DYSTONIA
HISTORY
DESCRIPTIONS BACK TO 18TH CENTURY
WITH SCRIBES REPORTING CRAMPING OF
HANDS ONLY WHEN PERFORMING THEIR
JOBS
ABLE TO PERFORM VIRTUALLY ALL OTHER
TASKS NORMALLY
“OCCUPATIONAL PALSY”
Albanese A. et al. Mov Disord. 2013 Jun 15; 28(7): 863-873.
LIMB DYSTONIA
WHAT IS IT???
REPRESENTS A FOCAL/TASK SPECIFIC DYSTONIA
UNCLEAR RELATIONSHIP TO PERIPHERAL/CENTRAL TRAUMA
ABERRANT PLASTICITY FROM EXCESSIVE, REPETITIVE USE
LIKELY THAT DISORDER IS A CONSEQUENCE OF REPETITIVE ACTIVITY ON BACKGROUND OF A GENETIC PREDISPOSITION
Furuya S, et al. Neurosci Res. 2016;104:112-119.
LIMB DYSTONIA
TASK SPECIFIC DYSTONIA
MAY OCCUR DURING SKILLED MANUAL
ACTIVITIES “OCCUPATIONAL CRAMPS”
OTHER DESCRIPTIONS INCLUDE STRING
MUSICIANS, PIANISTS,TYPISTS, TYPESETTERS,
SURGEONS
DIS-SIMILAR FROM ORTHOPEDIC OVER-USE
SYNDROMES AS DOES NOT IMPROVE WITH
REST
LIMB DYSTONIA
PATHOPHYSIOLOGY IMPAIRED INHIBITION AT MULTIPLE LEVELS OF THE
CNS
HALLETT ET AL DISTURBED SURROUND INHIBITION
WITH FAILURE TO SURPRESS NEURONAL
EXCITABILITY IN REGIONS SURROUNDING
ACTIVATED NEURAL CIRCUITS MAY CAUSE
OVERFLOW MOVEMENTS IN ADJACENT MUSCLES
SENSORIMOTOR REPRESENTATION OF AFFECTED
BODY PARTS IS ENLARGED IN THE CEREBRAL
CORTEX OF PATIENTS WITH FOCAL DYSTONIA
UNCLEAR IF SENSORI-MOTOR ABNORMALITIES
ARE PRIMARY OR SECONDARY???
Sohn YH, Hallett M. ANN NEUROL. 2004:OCT;56(4):595-599.
LIMB DYSTONIA
PATHOPHYSIOLOGY (TMS)
“IN CONCLUSION THESE FINDINGS FROM REACTION TIME TASKS IN PATIENTS WITH PRIMARY DYSTONIA PROVIDE EVIDENCE OF ABNORMAL PRE-MOVEMENT MOTOR CORTEX EXCITABILITY. THE ABNORMALITY IS DUE TO AN ALTERED RELEASE OR RUNNING OF MOTOR PROGRAMS.”
Gilio F, et al. Brain. 2003 Aug;126(Pt 8):1745-1754.
LIMB DYSTONIA
PATHOPHYSIOLOGY
“ In writers camp we found that HFO patterns are strongly decreased in power and disorganized in time This supports the assumption that abnormal HFOs reflect pathophysiological mechanisms occurring in focal dystonia, possibly resulting from a dysfunction of somatosensory processing”
Cimatti Z, et al. Brain. 2007 Jan;130(Pt 1):198-205.