Abstract Details

Title Motor Cortex Inhibition: A Marker of Motor Function in Neurofibromatosis Type 1

Topic Neuro-rehabilitation

Presentation(s) P16 - Poster Session 16 (8:00 AM-9:00 AM)

Poster/Presentation
Number 7-005

Objective To determine whether impaired motor function in patients with NF1 is linked to motor cortex inhibition.

Background Neurofibromatosis type 1 (NF1) is a neuro-cutaneous disorder commonly associated with motor and cognitive defects. These deficits lack effective treatment and greatly impact children’s quality of life. To complement subjective, symptom-based ratings, more reliable and objective measures are needed to assess effects of novel treatments. Transcranial magnetic stimulation (TMS) motor physiology measures may serve this purpose and provide a window into cortical motor dysfunction underlying both motor and cognitive deficits.

Design/Methods Youth ages 8 to 16 were recruited from an NF1 specialty clinic (n=22). Standard safety precautions and exclusions for TMS were applied. Developmental motor function was evaluated with the Physical and Neurological Examination for Soft Signs (PANESS) test. Motor cortex thresholds, inhibition, and facilitation were measured with single and paired pulse TMS. Single pulse TMS measures included Resting and Active Motor Threshold (RMT, AMT). Paired pulse TMS measures included short interval cortical inhibition (SICI) and intracortical facilitation (ICF). Spearman Rank Correlations were used to assess associations between developmental motor function, neurophysiological measures, and age.

Results Twenty-two youth (82% male, 100% white, non-Hispanic; mean age= 12) were recruited. Mean PANESS score was 47 (SD= 15.8), which falls in the highly impaired range. Worse motor function (higher PANESS scores) correlated with less motor cortex inhibition (SICI) (r=.58, p<0.01). Reduced SICI also correlated with several subscales (p<0.05), particularly slower timed tasks (r=.702, p<0.001). Similarly, slower timed tasks correlated with higher ICF and RMT. Motor function failed to demonstrate expected improvement with increasing age (p=0.88).

Conclusions Motor physiology assessed with TMS reflects motor function in youth with NF1. TMS SICI holds promise as a biomarker useful for clinical trials.

Authors/Disclosures
Alexander Doherty, MD PRESENTER	Mr. Doherty has received research support from National Institute of Health.
	No disclosure on file
	No disclosure on file
	No disclosure on file
Donald Gilbert, MD, FAAN (Cincinnati Children's Hospital Med. Ctr.)	Dr. Gilbert has received personal compensation in the range of $500-$4,999 for serving as a Consultant for PTC Therapeutics. Dr. Gilbert has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Illumina. Dr. Gilbert has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Emalex Biosciences. The institution of Dr. Gilbert has received research support from NIMH. The institution of Dr. Gilbert has received research support from Emalex Biosciences. The institution of Dr. Gilbert has received research support from PTC Therapeutics. The institution of Dr. Gilbert has received research support from Department of Defense. The institution of Dr. Gilbert has received research support from Quince Therapeutics. Dr. Gilbert has received publishing royalties from a publication relating to health care. Dr. Gilbert has received publishing royalties from a publication relating to health care. Dr. Gilbert has received personal compensation in the range of $500-$4,999 for serving as a Medical Second Opinion Expert with Teldoc/Advanced Medical. Dr. Gilbert has received personal compensation in the range of $10,000-$49,999 for serving as a Medical Expert with Department of Health and Human Services/Vaccine Injury Compensation Program.

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