PMID- 12429599
OWN - NLM
STAT- MEDLINE
DCOM- 20021231
LR  - 20190513
IS  - 0006-8950 (Print)
IS  - 0006-8950 (Linking)
VI  - 125
IP  - Pt 12
DP  - 2002 Dec
TI  - Abnormal somatotopic arrangement of sensorimotor interactions in dystonic 
      patients.
PG  - 2719-30
AB  - The aim of the study was to detect abnormalities of sensorimotor interactions and 
      their topographic distribution in the hand muscles of dystonic patients. We 
      investigated the effect of electrical stimulation of the second (D2) and fifth 
      (D5) fingers on the amplitude of motor evoked potentials (MEPs) in response to 
      transcranial magnetic stimulation (TMS) and transcranial electrical stimulation 
      (TES) in the relaxed first dorsal interosseous (FDI) and abductor digiti minimi 
      (ADM) muscles on both sides of eight patients with unilateral hand dystonia (HD) 
      and in four patients with cervical dystonia (CD). Six Parkinson's disease 
      patients were used as the disease control group and 10 healthy subjects served as 
      normal controls. For each muscle, the digital stimulation was applied to a 
      contiguous finger (CF) and to a non-contiguous finger (NCF). The digital 
      stimulation was set at three times the sensory threshold and preceded TMS or TES 
      at intervals ranging from 10 to 100 ms. In normal subjects, a somatotopic 
      inhibitory effect was detected, since the CF stimulation was significantly more 
      powerful in determining the reduction of MEPs in response to TMS at intervals 
      ranging from 20 to 50 ms. In dystonic patients, on the contrary, the somatopic 
      effect was not present, because both CF and NCF stimulation evoked a consistent 
      MEP inhibition and no significant difference was detected between the 
      conditioning effect of CF and NCF stimulation. These abnormalities were present 
      in the muscles of both the affected and unaffected hands of HD patients, as well 
      as in CD patients. TES conditioning provoked MEP inhibition only at interstimulus 
      intervals (ISIs) <40 ms. Significant MEP potentiation was found at ISIs of 20-40 
      ms to CF stimulation in Parkinson's disease patients, while there was no effect 
      after NCF stimulation. These data suggest that MEP suppression in response to 
      digital stimulation is preserved in dystonia, but the somatotopically distributed 
      input-output organization of the sensorimotor interactions is lost in dystonic 
      patients' hands. The comparison between TMS and TES experiments indicates that 
      abnormalities may be present at both the spinal and the cortical level, at least 
      in some patients. These findings suggest that a mechanism that normally operates 
      in order to focus the effect of somatosensory afferences on the motor system may 
      be impaired in dystonia. This abnormality seems specific to dystonia.
FAU - Tamburin, Stefano
AU  - Tamburin S
AD  - Sections of Neurological Rehabilitation, Clinical Neurology and Human Physiology, 
      Department of Neurological Sciences and Vision, University of Verona, Italy. 
      s_tamburin@yahoo.com
FAU - Manganotti, Paolo
AU  - Manganotti P
FAU - Marzi, Carlo Alberto
AU  - Marzi CA
FAU - Fiaschi, Antonio
AU  - Fiaschi A
FAU - Zanette, Giampietro
AU  - Zanette G
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - England
TA  - Brain
JT  - Brain : a journal of neurology
JID - 0372537
SB  - IM
MH  - Adult
MH  - Aged
MH  - Analysis of Variance
MH  - Dystonic Disorders/*physiopathology
MH  - Electric Stimulation/methods
MH  - Electromagnetic Phenomena/methods
MH  - Evoked Potentials, Motor/*physiology
MH  - Female
MH  - Fingers/physiology
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Parkinson Disease/physiopathology
MH  - Psychomotor Performance/*physiology
EDAT- 2002/11/14 04:00
MHDA- 2003/01/01 04:00
CRDT- 2002/11/14 04:00
PHST- 2002/11/14 04:00 [pubmed]
PHST- 2003/01/01 04:00 [medline]
PHST- 2002/11/14 04:00 [entrez]
AID - 10.1093/brain/awf279 [doi]
PST - ppublish
SO  - Brain. 2002 Dec;125(Pt 12):2719-30. doi: 10.1093/brain/awf279.