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Cerebellar metabolic symmetry in essential tremor studied with 1H magnetic resonance spectroscopic imaging: Implications for disease pathology

Authors

  • Elan D. Louis MD, MS,

    Corresponding author
    1. Gertrude H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, USA
    2. Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
    3. Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York, USA
    • Unit 198, Neurological Institute, 710 West 168th Street, New York, NY, 10032
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  • Dikoma C. Shungu PhD,

    1. Department of Radiology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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  • Xiangling Mao MS,

    1. Department of Radiology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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  • Steven Chan MD, MBA, MPH,

    1. Department of Radiology, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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  • Eva C. Jurewicz BA

    1. Gertrude H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, USA
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Abstract

The pathological basis for essential tremor (ET) is not known; however, metabolic changes in the cerebellum can be observed in positron emission tomography (PET) and 1H magnetic resonance spectroscopic imaging (MRSI) studies. Tremor is relatively symmetric in ET, suggesting that underlying metabolic changes could be also symmetric. The degree of metabolic asymmetry in the cerebellum, however, has not yet been studied in ET, and knowledge about distribution and laterality of metabolic changes might shed some light on basic disease mechanisms. We measured brain metabolism (N-acetylaspartate[NAA]/creatine [tCR]) to obtain an asymmetry index for cerebellar cortical metabolism ET patients compared with that in controls. This index, a percentage, was calculated as |(value right − value left)|/(value right + value left) × 100. Multislice 1H MRSI data were acquired for 20 patients and 11 controls. In ET patients, mean right and left cerebellar cortical NAA/tCR values were 1.61 ± 0.42 and 1.55 ± 0.38, respectively, compared with 1.81 ± 0.62 and 1.87 ± 0.49 in controls. The difference between right and left cerebellar cortical NAA/tCR was also calculated for each subject. In ET patients, the mean right-left difference was 0.14 ± 0.11, compared with 0.32 ± 0.27 in controls (P = 0.016). The mean cerebellar cortical asymmetry index was low in ET (8.8 ± 6.1%), one-half of that in controls (17.0 ± 13.7%, P = 0.027). These data suggest that pathological lesions in ET patients, which remain elusive, might be distributed similarly in each cerebellar cortex. Postmortem studies are needed to confirm these preliminary imaging results. © 2004 Movement Disorder Society

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