1H-MRS alterations in the cerebellum of patients with familial hemiplegic migraine type 1.
BACKGROUND
About 20% of patients with familial hemiplegic migraine (FHM) develop progressive cerebellar signs. Genetic studies have established an association with mutations in the CACNA1A gene. However, the mechanisms underlying cerebellar involvement are largely unknown.


OBJECTIVE
To use proton MR spectroscopy (1H-MRS) to investigate metabolic alterations in the cerebellum as well as cortical regions known to be involved in the propagation of migraine aura.


METHODS
Fifteen CACNA1A mutation carriers from three FHM families and 17 healthy control subjects were studied. Eleven patients had clinical signs of cerebellar involvement. LCModel fits were used to estimate absolute concentrations of N-acetyl aspartate (NAA), myo-inositol (mI), glutamate (Glu), choline-containing compounds, total creatine, and lactate in the superior cerebellar vermis (SCV), parietal cortex, and occipital cortex. To control for atrophy effects, automated image segmentation was performed using SPM99. The brain parenchyma fraction (BPF) was determined for all three regions.


RESULTS
Compared with controls, the brain parenchyma fraction (BPF), NAA, and Glu were significantly reduced and mI was significantly elevated in the SCV of patients with FHM. In contrast, no metabolite alterations were found in supratentorial regions. BPF and NAA in the SCV significantly correlated with cerebellar scores, in particular, gait ataxia.


CONCLUSIONS
The findings suggest that there is a regionally distinct neuronal impairment in the superior cerebellar vermis that exceeds macroscopic tissue loss. Correlations with clinical scores emphasize the functional relevance of localized atrophy (brain parenchyma fraction) and N-acetyl aspartate levels. These measures may be useful to monitor disease progression. The observed reduction in glutamate may in part reflect impaired glutamatergic neurotransmission.
Dichgans
M
M
Department of Neurology, Klinikum Grosshadern, Ludwig Maximilians University, Munich, Germany. mdichgans@nefo.med.uni-muenchen.de
Herzog
J
J
Freilinger
T
T
Wilke
M
M
Auer
D P
DP
D000293:Adolescent; D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D001923:Brain Chemistry; D015220:Calcium Channels / Q000235:genetics / Q000502:physiology; D002531:Cerebellum / Q000737:chemistry*; D002794:Choline / Q000032:analysis; D003401:Creatine / Q000032:analysis; D004401:Dysarthria / Q000209:etiology / Q000378:metabolism; D020329:Essential Tremor / Q000209:etiology / Q000378:metabolism; D005260:Female; D020234:Gait Ataxia / Q000209:etiology / Q000378:metabolism; D018698:Glutamic Acid / Q000032:analysis; D006429:Hemiplegia / Q000209:etiology / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D007294:Inositol / Q000032:analysis; D007773:Lactates / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D020325:Migraine with Aura / Q000209:etiology / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D009154:Mutation; D010296:Parietal Lobe / Q000737:chemistry; D014793:Visual Cortex / Q000737:chemistry; D020864:Calcium Channels, N-Type
D001224:Aspartic Acid; D015220:Calcium Channels; D002794:Choline; D003401:Creatine; D018698:Glutamic Acid; D007294:Inositol; D007773:Lactates; C105656:CACNA1A protein, human; D020864:Calcium Channels, N-Type; C000179:N-acetylaspartate