Abnormal cortical excitability with preserved brainstem and spinal reflexes in sialidosis type I.
OBJECTIVE
To examine neurophysiological evidence of functional involvement of the brainstem and spinal cord and motor cortical excitability in sialidosis type I, a rare inherited neurodegenerative disorder caused by mutations in the NEU1 gene.


METHODS
We investigated particular pathways in the brainstem, spinal cord and motor cortex in 12 genetically proven cases of sialidosis type I by assessing blink reflex recovery cycle (BR), spinal reciprocal inhibition (RI), input-output curves (I/O), short interval intracortical inhibition (SICI), intracortical facilitation (ICF) and silent period (SP).


RESULTS
The BR and RI were normal. The slope of I/O was significantly increased, and SICI and the duration of SP were reduced in sialidosis patients.


CONCLUSIONS
Despite reports of pathology involving brainstem and anterior horn neurones, there were no obvious abnormalities in spinal and brainstem reflexes in the present patients, suggesting that the major clinical effects may be caused by changes at a level above the brainstem.


CONCLUSIONS
For the first time, the integrity of certain brainstem and spinal cord reflexes in addition to motor cortical facilitatory and inhibitory circuits has been assessed in genetically proven type I sialidosis. This provides new data to aid in understanding of the pathophysiology of motor system dysfunction in this condition.
Huang
Ying-Zu
YZ
Department of Neurology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, 199, Dunhwa North Road, Taipei 10507, Taiwan.
Lai
Szu-Chia
SC
Lu
Chin-Song
CS
Weng
Yi-Hsin
YH
Chuang
Wen-Li
WL
Chen
Rou-Shayn
RS
D000328:Adult; D001767:Blinking / Q000502:physiology; D001933:Brain Stem / Q000502:physiology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009081:Mucolipidoses / Q000503:physiopathology*; D012018:Reflex / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation