Abstract Details

Title Pathophysiological Changes in the H-Reflex Pathway in Amyotrophic Lateral Sclerosis

Topic Anterior Horn

Presentation(s) P07 - (-)

Poster/Presentation
Number 075

Objective

Background BACKGROUND: The H-reflex has been used extensively as a biomarker of UMN dysfunction in neurological disorders, but its suitability as a biomarker in ALS has not been established.

Design/Methods DESIGN/METHODS: Recruitment curves for the soleus H-reflex and M-wave were recorded in 20 patients with ALS (40 LLs) and 27 normal control subjects (53 LLs). Analyzed parameters included the minimum intensity required to produce an H-reflex (Hthresh) and M-wave (Mthresh), the ratio of maximal H-reflex and M-wave amplitude (Hmax/Mmax), and the average of H-reflex amplitudes corresponding to M-waves of 1-5mV (Hmean). The slope angle of the linear ascending portion of the H and M recruitment curves was calculated and Hslp/Mslp was derived. Quantitative scales of clinical UMN and lower motor neuron dysfunction were incorporated into multiple linear regression models for Hmax/Mmax and Hslp/Mslp.

Results RESULTS: Mmax was significantly lower in the ALS group (P<0.001) but Hmax/Mmax was similar between groups. Hslp/Mslp was significantly higher in the ALS group (p<0.05), a result of reduced Mslp rather than increased Hslp. Hmax/Mmax was predicted by clinical UMN dysfunction, but was also noted to decrease significantly with age. Further analysis suggested that Hmax/Mmax in ALS patients may be attenuated by confounding electrophysiological phenomena, in particular collision by antidromically conducted impulses in directly stimulated motor axons. Hslp/Mslp was strongly predicted by clinical UMN dysfunction (Beta=0.662, t=4.932, p<0.001), without influence of other measured variables. Analysis of the pattern of Hslp/Mslp provided support for the hypothesis that reduction in spinal recurrent inhibition may contribute to clinical UMN signs in ALS.

Conclusions CONCLUSIONS: Hslp/Mslp correlated with clinical severity of UMN dysfunction in ALS and may be useful as an objective biomarker in longitudinal studies or clinical trials of treatment efficacy.

Authors/Disclosures
Neil G. Simon, MD PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Matthew C. Kiernan, MBBS, PhD, FRACP (Neuroscience Research Australia)	The institution of Prof. Kiernan has received personal compensation in the range of $50,000-$99,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for British Medical Journal Publishers (UK).
	No disclosure on file

��ɫ��

��ɫ��