Journal Article (Review Article)

DZNE-2026-00790

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png ALS motor phenotypes: a revised 'OPM' classification.

Meyer, T. ; Ticozzi, N. ; Weber, M. ; Ravits, J. ; Lingor, P.DZNE* ; Kuźma-Kozakiewicz, M. ; Boentert, M. ; Grehl, T. ; Corcia, P. ; Povedano Panadés, M. ; Maier, A. ; Ingre, C. ; Cetin, H. ; Weydt, P.DZNE* ; Lunetta, C. ; van den Berg, L. ; Ludolph, A.Extern* ; Brenner, D.Extern* ; Turner, M. R. ; Genge, A.

2026
Taylor Francis Group Abingdon

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Please use a persistent id in citations: doi:10.1080/21678421.2026.2644277

Abstract: Defining motor phenotypes in amyotrophic lateral sclerosis (ALS) is important for individualized care and optimal therapeutic trial design. The 'ALS-OPM' classification is based on the onset region (O), the propagation of motor symptoms (P), and the degree of clinical upper (UMN) and/or lower (LMN) motor neuron dysfunction (M).An international ALS expert focus group was held in September 2025, followed by a consensus process through which revisions of the OPM classification were finalized.Onset (O1-4) identifies first motor symptoms as relating to the head (O1), distal/proximal arm (O2d/p), respiratory/axial trunk (O3r/a), or distal/proximal leg (O4d/p). Onset symptoms are defined by weakness or slowed, poorly coordinated voluntary movements in the muscles of the head, arm, trunk, or leg, including dysarthria, dysphagia, dysphonia, dyspnea, and axial instability. Propagation (P1(n)) or absence of propagation (P0(n)) of motor symptoms from the onset region to another body region are designated, where n denotes the number of months from onset to propagation or assessment. The degree of UMN dysfunction (slowed, poorly coordinated voluntary movements, hyperreflexia and/or spastic muscle tone, emotional lability) and/or LMN dysfunction (weakness with associated muscle atrophy) is classified as follows: balanced UMN and LMN dysfunction (M0); dominant (M1d) or pure UMN dysfunction (M1p); dominant (M2d) or pure LMN dysfunction (M2p); and dissociated UMN/LMN dysfunction (M3), in which the arms and legs predominantly show LMN and UMN involvement, respectively.The revised ALS-OPM classification aims to make it routine, practical and feasible to capture phenotype in clinical practice and therapeutic trials.

Keyword(s): Humans (MeSH) ; Amyotrophic Lateral Sclerosis: physiopathology (MeSH) ; Amyotrophic Lateral Sclerosis: classification (MeSH) ; Amyotrophic Lateral Sclerosis: diagnosis (MeSH) ; Phenotype (MeSH) ; Motor Neurons: physiology (MeSH) ; ALS motor phenotypes ; Amyotrophic lateral sclerosis ; OPM ; classification ; revision

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Contributing Institute(s):

1. Clinical Research (Munich) (Clinical Research (Munich))
2. Clinical Research Coordination (Clinical Research (Bonn))

Research Program(s):

1. 353 - Clinical and Health Care Research (POF4-353) (POF4-353)

Appears in the scientific report 2026

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Clinical Medicine ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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