Reduced brain stem excitability in mitochondrial myopathy: Evidence for early detection with blink reflex habituation studies
✍ Scribed by Michael Koutroumanidis; Alexander Papadimitriou; Evrydiki Bouzas; Theodoros Avramidis; Panayiotis Papathanassopoulos; Robin S. Howard; Theodoros Papapetropoulos
- Book ID
- 102653916
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 859 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0148-639X
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✦ Synopsis
Blink reflex (BR) was studied in 17 patients with histochemically and genetically confirmed mitochondrial myopathy (MM). Fourteen patients had chronic progressive external ophthalmoplegia (CPEO) associated with a mild to moderate craniosomatic myopathy without any symptoms or signs of central nervous system (CNS) involvement, 2 myoclonic epilepsy with ragged red fibers syndrome, and 1 Kearns-Sayre syndrome. The mean latencies of the early (RI) and late (R2) responses were prolonged ( P < 0.01 and P < 0.001, respectively), and the corresponding amplitudes decreased ( P < 0.001). Increased habituation of the reflex was clearly observed in 10 out of 14 patients tested (71.4%), 9 of whom presented CPEO. These findings suggest that the brain stem reticular network is in a state of basal inhibition which is presumably due to a subclinical impairment of the cerebral cellular metabolism. Multimodal evoked potentials revealed abnormalities suggestive of CNS involvement in 7 out of 17 patients (41.2%), 4 of whom had CPEO. These observations document the validity of BR in detecting clinically silent brain stem impairment in patients with apparently pure MM and provide important clues for a further understanding of the underlying pathophysiology. 0