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Kernohan's notch phenomenon demonstrated by diffusion tensor imaging and transcranial magnetic stimulation
1Department of Physical Medicine and Rehabilitation Medicine, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea.
Journal of Neurology, Neurosurgery, and Psychiatry
|October 23, 2008
Summary
Kernohan's notch phenomenon, causing hemiplegia, was demonstrated using diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS). These techniques revealed corticospinal tract damage in the midbrain, despite the subdural hematoma being on the opposite side.
Area of Science:
- Neuroscience
- Radiology
- Neurology
Background:
- Kernohan's notch phenomenon involves contralateral cerebral peduncle compression by supratentorial masses.
- Diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS) are valuable for assessing the corticospinal tract (CST).
Purpose of the Study:
- To demonstrate Kernohan's notch phenomenon in a subdural hematoma patient using DTI and TMS.
- To investigate the state of the corticospinal tract in a case of Kernohan's notch phenomenon.
Main Methods:
- Recruitment of one patient with subdural hematoma and six healthy controls.
- Performance of DTI and TMS at 6 weeks post-onset.
- Brain CT and T2-weighted MRI for lesion identification.
Main Results:
- Patient presented with right hemiplegia despite a right-sided subdural hematoma.
- DTI showed decreased fractional anisotropy in the left midbrain and medulla, with CST interruption.
- TMS revealed delayed latency, low amplitude, and higher excitatory threshold in right hand motor evoked potentials, indicating left CST damage.
Conclusions:
- The study successfully demonstrated Kernohan's notch phenomenon using DTI and TMS.
- Findings suggest CST damage occurred in the left midbrain, consistent with the contralateral hemiplegia observed.
