Editing Motor neuron diseases (section)

== Signs and symptoms ==
[[File:ALS clinical picture.png|thumb|325x325px|A man with [[amyotrophic lateral sclerosis]] (ALS). (A) He needs assistance to stand. (B) Advanced atrophy of the tongue. (C) There is upper limb and truncal muscle atrophy with a positive [[Babinski sign]]. (D) Advanced [[thenar muscle]] atrophy.<ref>{{Cite web|title=Patient with amyotrophic lateral sclerosis (ALS) (case {{!}} Open-i|url=https://openi.nlm.nih.gov/detailedresult.php?img=3996815_bmjopen2013004353f02&query=amyotrophic+lateral+sclerosis&it=xg&lic=by&req=4&npos=5|website=openi.nlm.nih.gov|url-status=dead|archive-url=https://web.archive.org/web/20181215225214/https://openi.nlm.nih.gov/detailedresult.php?img=3996815_bmjopen2013004353f02&query=amyotrophic+lateral+sclerosis&it=xg&lic=by&req=4&npos=5|archive-date=15 December 2018|access-date=2018-12-12}}</ref>]]
Signs and symptoms depend on the specific disease, but motor neuron diseases typically manifest as a group of movement-related symptoms.<ref name=":7">{{cite journal | vauthors = Statland JM, Barohn RJ, McVey AL, Katz JS, Dimachkie MM | title = Patterns of Weakness, Classification of Motor Neuron Disease, and Clinical Diagnosis of Sporadic Amyotrophic Lateral Sclerosis | journal = Neurologic Clinics | volume = 33 | issue = 4 | pages = 735–748 | date = November 2015 | pmid = 26515618 | pmc = 4629510 | doi = 10.1016/j.ncl.2015.07.006 }}</ref> They come on slowly, and worsen over the course of more than three months. Various patterns of muscle weakness are seen, and muscle cramps and spasms may occur. One can have difficulty breathing with climbing stairs ([[exertion]]), difficulty breathing when lying down ([[orthopnea]]), or even [[respiratory failure]] if breathing muscles become involved. [[Bulbar]] symptoms, including difficulty speaking ([[dysarthria]]), difficulty swallowing ([[dysphagia]]), and excessive saliva production ([[Hypersalivation|sialorrhea]]), can also occur. Sensation, or the ability to feel, is typically not affected. Emotional disturbance (e.g. [[pseudobulbar affect]]) and cognitive and behavioural changes (e.g. problems in word fluency, decision-making, and memory) are also seen.<ref name="NINDS2014" /><ref name=":7" /> There can be lower motor neuron findings (e.g. muscle wasting, muscle twitching), upper motor neuron findings (e.g. brisk reflexes, [[Plantar reflex|Babinski reflex]], [[Hoffmann's reflex|Hoffman's reflex]], increased muscle tone), or both.<ref name=":7" />

Motor neuron diseases are seen both in children and adults.<ref name="NINDS2014" /> Those that affect children tend to be inherited or familial, and their symptoms are either present at birth or appear before learning to walk. Those that affect adults tend to appear after age 40.<ref name="NINDS2014" /> The clinical course depends on the specific disease, but most progress or worsen over the course of months.<ref name=":7" /> Some are fatal (e.g. ALS), while others are not (e.g. PLS).<ref name="NINDS2014" />

=== Patterns of weakness ===
Various patterns of muscle weakness occur in different motor neuron diseases.<ref name=":7" /> Weakness can be symmetric or asymmetric, and it can occur in body parts that are distal, proximal, or both. According to Statland et al., there are three main weakness patterns that are seen in motor neuron diseases, which are:<ref name=":7" /><ref>{{cite journal | vauthors = Barohn RJ, Amato AA | title = Pattern-recognition approach to neuropathy and neuronopathy | journal = Neurologic Clinics | volume = 31 | issue = 2 | pages = 343–361 | date = May 2013 | pmid = 23642713 | pmc = 3922643 | doi = 10.1016/j.ncl.2013.02.001 }}</ref>

# Asymmetric distal weakness without sensory loss (e.g. ALS, PLS, PMA, MMA)
# Symmetric weakness without sensory loss (e.g. PMA, PLS)
# Symmetric focal midline proximal weakness (neck, trunk, bulbar involvement; e.g. ALS, PBP, PLS)

=== Lower and upper motor neuron findings ===
Motor neuron diseases are on a spectrum in terms of upper and lower motor neuron involvement.<ref name=":7" /> Some have just lower or upper motor neuron findings, while others have a mix of both. Lower motor neuron (LMN) findings include muscle [[atrophy]] and [[fasciculation]]s, and upper motor neuron (UMN) findings include [[hyperreflexia]], spasticity, muscle spasm, and abnormal reflexes.<ref name="NINDS2014" /><ref name=":7" />

Pure upper motor neuron diseases, or those with just UMN findings, include PLS.<ref>{{cite book | vauthors = Emos MC, Agarwal S | chapter = Neuroanatomy, Upper Motor Neuron Lesion |date=2022 | chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK537305/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=30725990 |access-date=2022-06-24 }}</ref>

Pure lower motor neuron diseases, or those with just LMN findings, include PMA.<ref>{{Cite web |title=Progressive Muscular Atrophy – an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/neuroscience/progressive-muscular-atrophy |access-date=2022-06-24 |website=sciencedirect.com}}</ref>

Motor neuron diseases with both UMN and LMN findings include both familial and sporadic ALS.<ref>{{Cite web |title=Motor Neuron Diseases Fact Sheet {{!}} National Institute of Neurological Disorders and Stroke |url=https://www.ninds.nih.gov/health-information/patient-caregiver-education/fact-sheets/motor-neuron-diseases-fact-sheet |access-date=2022-06-24 |website=ninds.nih.gov}}</ref>