Last reviewed: 19 Dec 2021
Last updated: 10 Mar 2020



History and exam

Key diagnostic factors

  • presence of risk factors
  • upper extremity weakness
  • stiffness, with poor co-ordination and balance
  • spastic, unsteady gait
  • painful muscle spasms
  • difficulties in arising from chairs and climbing stairs
  • foot drop
  • stiffness and decreased balance with impact on gait
  • head drop
  • progressive difficulties in maintaining erect posture, with stooping
  • muscle atrophy
  • increased lumbar lordosis and tendency for abdominal protuberance
  • hyper-reflexia
  • dyspnoea
  • coughing and choking on liquids (including secretions) and eventually on food
  • strained, slow speech
  • slurred, nasal, and, at times, dysphonic speech

Other diagnostic factors

  • propensity for falls
  • sialorrhoea and drooling
  • inappropriate bursts of crying or laughing
  • cognitive impairment
  • features of frontotemporal dementia

Risk factors

  • genetic predisposition or family history
  • age >40 years
  • military service
  • professional athletic activity
  • cigarette smoking
  • agricultural chemical exposure
  • lead exposure

Diagnostic investigations

Investigations to consider

  • electromyography (EMG)
  • repetitive nerve stimulation
  • MRI brain and spine
  • anti-GM1 antibodies
  • voltage-gated calcium-channel antibodies
  • acetylcholine receptor antibodies
  • vitamin B₁₂
  • creatine kinase
  • lumbar puncture
  • HIV test
  • genetic testing

Treatment algorithm



Christopher J. McDermott, MBChB, FRCP, PhD

Professor of Translational Neurology and Honorary Consultant Neurologist

University of Sheffield

Faculty of Medicine, Dentistry and Health

Department of Neuroscience

Sheffield Institute for Translational Neuroscience




CJM has received fees for membership of data monitoring committees from Orion Pharma and Orphazyme.


Professor Christopher J. McDermott would like to gratefully acknowledge Dr Laura Simionescu and Dr Jeremy Shefner, previous contributors to this topic. LS and JS declare that they have no competing interests.

Peer reviewers

David S. William, MD, PhD

Associate Professor of Neurology

Harvard Medical School




DSW declares that he has no competing interests.

Leo McCluskey, MD MBE

Associate Professor of Neurology

University of Pennsylvania




LM declares that he has no competing interests.

Martin R. Turner, MA, MBBS, PhD, MRCP

MRC/MNDA Lady Edith Wolfson Clinician Scientist & Honorary Consultant Neurologist

Oxford University Department of Clinical Neurology

John Radcliffe Hospital




MRT is a co-author of "Motor Neuron Disease – A Practical Manual" (Oxford University Press, 2010), which is a summary of his own understanding and practice, and which strongly influenced the recommendations for revision of the current article. He receives a proportion of royalties derived from sales of this book.

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