P2.15 Differential cortical activation during observation and imaging

Introduction: Familial cortical myoclonic tremor (FCMT) is a rare autosomal dominant disease characterized by involuntary oscillatory myoclonic jerks and generalized epilepsy. In papers are described Japanese and European families. It is usually misdiagnosed as Essential tremor.

Objective: We present a Spanish case of FCMT in order to emphasized the role of the neurophysiological test in the clinical diagnosy. Material and Methods: A 67 year-old woman who has been suffering of tremor in both arms for ten years and in low extremities for the last year. The tremor is present during writting and carrying out motor activities. Sensitivity to bright contrast was disabling. She had increased myoclonic jerks when driving on tree-line roads and looking at intense visual contrast. The neurological examination showed postural tremor in arms with intentional component in low members. The brain CT scan and MRI were normal. Additionally she was diagnosed of retinosis pigmentary and has had two episodes of loss of knowledge. The Valproate treatment improved the clinical symtoms. Her older sister is also affected.

Results: The EEG showed normal background with generalized Spike and polyspike-wave complexes. The intermittent photic stimulation provoked phtomyoclonic response with cortical myoclonics. These responses persisted with red, blue and yellow color filtres, but was not present with green color filter. The arm SSEPs were giants (range 14.5 18), with normal latency and morphology.

Conclusion: Electrophisiological Studies, including EEG, SSEPs and tremor recording can be easily elicited and are mandatory to confirm the diagnosis of FCMT.