Assessing Corticospinal Tract Asymmetry in Unilateral Polymicrogyria

Foesleitner, Olivia; Nenning, Karl-Heinz; Traub-Weidinger, Tatjana; Feucht, Martha; Bonelli, S; Czech, Thomas; Dorfer, Christian; Prayer, Daniela; Kasprian, Gregor

doi:10.3174/ajnr.a5715

Cited by 5 publications

(5 citation statements)

References 20 publications

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“…However, neither study involved brainstem atrophy. Although MRI [ 2 ] and DTI [ 11 ] have been previously used to assess unilateral polymicrogyria, TMS not used in that study.…”

Section: Discussionmentioning

confidence: 99%

Motor organization of unilateral polymicrogyria associated with ipsilateral brainstem atrophy – a case report

Roh

Kim

et al. 2022

BMC Neurol

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Background Polymicrogyria refers to the disruption of normal cerebral cortical development late in neuronal migration or in early cortical organization. Although patients with polymicrogyria feature relatively favorable motor outcomes, polymicrogyric lesions accompanied by extensive unilateral hemispheric atrophy and ipsilateral brainstem atrophy may induce poorer motor outcomes. This study is the first to employ transcranial magnetic stimulation (TMS) and diffusion tensor imaging (DTI) to characterize changes to motor organization and white matter tracts induced by polymicrogyria. Case presentation We document a case of a 16-year-old female with left hemiplegic unilateral polymicrogyria associated with ipsilateral brainstem atrophy. Magnetic resonance imaging (MRI) of the brain revealed unilateral polymicrogyria to have affected anterior cortical areas, including the perisylvian region on the right side. The right halves of the brain and brainstem were significantly smaller than the left halves. Although our patient was found to exhibit cortical dysplasia of the right frontoparietal and sylvian fissure areas and a decreased number of fibers in the corticospinal tract (CST) of the affected side on DTI, the connectivity of the CST was preserved up to the motor cortex. We also measured the cross-sectional area of the CST at the level of the pons. In TMS, contralateral motor evoked potentials (MEPs) were evoked from both hands, but the ipsilateral MEPs were evoked only from the left hand. The left hand featured a long duration, polyphasic pattern of contralateral MEPs. Discussion and conclusion TMS revealed that the concurrent bilateral projections to the paretic hand from the affected and unaffected hemispheres and contralateral MEPs in the paretic hand were polyphasic, indicating delayed electrophysiological maturation or a pathologic condition of the corticospinal motor pathways. In DTI, the cross-sectional area of the CST at the level of the pons on the affected side was smaller than that on the unaffected side. These DTI findings reveal an inadequate CST volume. Despite extensive brain malformation and ipsilateral brainstem atrophy, our patient had less severe motor dysfunction and presented with involuntary mirror movements. Mirror movements in the paretic hand are considered to indicate ipsilateral corticospinal projections from the unaffected hemisphere and may suggest favorable motor outcomes in early brain injury.

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“…However, neither study involved brainstem atrophy. Although MRI [ 2 ] and DTI [ 11 ] have been previously used to assess unilateral polymicrogyria, TMS not used in that study.…”

Section: Discussionmentioning

confidence: 99%

Motor organization of unilateral polymicrogyria associated with ipsilateral brainstem atrophy – a case report

Roh

Kim

et al. 2022

BMC Neurol

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“…Activation within morphologically abnormal regions is seen in majority of cases of polymicrogyria (PMG), Schizencephaly and FCD I and in a large proportion of FCD II and heterotopia cases (Janszky et al, 2003). Short range connectome studies reveal evidence not only for the preservation of the original activity in heterotopic, “double cortex” and unilateral PMG lesions but also the presence of ipsilateral connectivity and can predict preservation of motor functions (Foesleitner et al, 2018). Prof.…”

Section: Morphology Function and The Plastic Brainmentioning

confidence: 99%

Building Bridges Between the Clinic and the Laboratory: A Meeting Review – Brain Malformations: A Roadmap for Future Research

Sapir

Barakat

Paredes

et al. 2019

Front. Cell. Neurosci.

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In the middle of March 2019, a group of scientists and clinicians (as well as those who wear both hats) gathered in the green campus of the Weizmann Institute of Science to share recent scientific findings, to establish collaborations, and to discuss future directions for better diagnosis, etiology modeling and treatment of brain malformations. One hundred fifty scientists from twenty-two countries took part in this meeting. Thirty-eight talks were presented and as many as twenty-five posters were displayed. This review is aimed at presenting some of the highlights that the audience was exposed to during the three-day meeting.

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“…Patient Rater A Rater B Agreement 1 1 1 Yes 2 0 1 N o 3 0 0 Yes 4 1 1 Yes 5 0 0 Yes 6 1 1 Yes 7 1 1 Yes 8 1 1 Yes 9 0 0 Yes a 1 ϭ asymmetry, 0 ϭ symmetry (data published in Foesleitner et al 1 ).…”

Section: Assessment Of the Corticospinal Tract Asymmetry By Raters A mentioning

confidence: 99%

Reply:

Foesleitner¹,

Nenning²,

Traub-Weidinger³

et al. 2018

AJNR Am J Neuroradiol

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W e would like to comment on the letter to the Editor regarding our article on corticospinal tract asymmetries in unilateral polymicrogyria. 1 We thank Drs Jalalvandi and Naderi for their interest in our work and appreciate the opportunity to respond to their remarks. In most radiologic studies, the value is commonly used to assess interrater reliability. However, as emphasized by the authors and initially shown by Byrt et al, 2 it has important weaknesses due to bias and prevalence issues. Byrt et al recommended using the bias and the prevalence indices to address these shortcomings. In addition to several other observations, we documented a high concordance in detecting the presence or absence of corticospinal tract asymmetry in cases of unilateral polymicrogyria by 2 independent observers (9/10 consistent ratings, Table). The low bias (0.22) and prevalence (0.11) indices support the validity of our values. If, however, one wanted to use the prevalence-adjusted bias-adjusted , 2 in our case reaching 0.78, interrater agreement would still show a substantial strength of agreement. 2,3 Because the issues mentioned above do not apply to our sample, we opted for the classic value. In conclusion, we support the call of the letter for caution when using the coefficient. However, the issue of neither prevalence nor bias is relevant for our study. Thus, our results allow the conclusion of reliable visual assessment of corticospinal tract asymmetry in unilateral polymicrogyria involving the motor cortex based on T1-weighted and color-coded diffusion tensor imaging maps at the level of the midbrain.

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Assessing Corticospinal Tract Asymmetry in Unilateral Polymicrogyria

Cited by 5 publications

References 20 publications

Motor organization of unilateral polymicrogyria associated with ipsilateral brainstem atrophy – a case report

Motor organization of unilateral polymicrogyria associated with ipsilateral brainstem atrophy – a case report

Building Bridges Between the Clinic and the Laboratory: A Meeting Review – Brain Malformations: A Roadmap for Future Research

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