Cogwheel rigidity: Definition, causes, and testing Health ConditionsHealth ConditionsAlzheimer's & DementiaAnxietyArthritisAsthma & AllergiesBreast CancerCancerCardiovascular HealthCOVID-19Dermatology & SkincareDiabetesEnvironment & SustainabilityExercise & FitnessEye HealthHeadache & MigraineHealth EquityHIV & AIDSHuman BiologyInflammatory Bowel DiseaseLeukemiaLGBTQIA+Men's HealthMental HealthMultiple Sclerosis (MS)NutritionParkinson's DiseasePsoriasisSexual HealthWomen's HealthDiscoverNewsLatest NewsOriginal SeriesMedical MythsHonest NutritionThrough My EyesNew Normal HealthPodcastsHow to understand chronic painWhat is behind vaccine hesitancy?The amazing story of hepatitis C, from discovery to cureNew directions in dementia researchCan psychedelics rewire a depressed, anxious brain?Why climate change matters for human healthToolsGeneral HealthDrugs A-ZHealth HubsHealth ToolsBMI Calculators and ChartsBlood Pressure Chart: Ranges and GuideBreast Cancer: Self-Examination GuideSleep CalculatorHealth ProductsAffordable Therapy OptionsBlood Pressure MonitorsDiabetic SuppliesFitness TrackersHome GymsGreen Cleaning ProductsHow to Shop for CBDQuizzesRA Myths vs FactsType 2 Diabetes: Managing Blood SugarAnkylosing Spondylitis Pain: Fact or FictionConnectAbout Medical News TodayWho We AreOur Editorial ProcessContent IntegrityConscious LanguageNewslettersSign UpFollow UsMedical News TodayHealth ConditionsDiscoverToolsConnectSubscribe What to know about cogwheel rigidityMedically reviewed by Heidi Moawad, M.D. — By Lorenzo Lucchetti on September 27, 2022Cogwheel rigidity refers to a potential early sign of Parkinson’s disease. It describes a type of rigidity that typically affects the limbs, causing them to move in small increments, similar to how gears move. Also known as cogwheel phenomenon or cogwheeling, this type of rigidity refers to a potential movement-related sign of Parkinson’s disease. Parkinson’s disease is a neurodegenerative condition that affects movement, typically due to low levels of dopamine activity in the brain. This neurotransmitter plays an important role in movement and coordination, and low levels can result in muscle stiffness and cogwheel rigidity. In this article, we discuss cogwheel rigidity in more detail, including its causes and how doctors test for it. Definition Share on PinterestLuis Alvarez/Getty ImagesHealth experts define cogwheel rigidity as a type of stiffness in which a limb reacts with cogwheel-like jerks during attempted movement. Rigidity is one of the four primary symptoms of Parkinson’s disease, alongside these other motor symptoms: bradykinesiatremorsproblems with balance Cogwheel rigidity is an important diagnostic feature of the physical exam for Parkinson’s disease. A person may experience it in any limb. In some cases, a person might not notice rigidity during their day-to-day life, but a doctor can detect this type of movement during a physical examination. Symptoms Rigidity is one of the main symptoms of Parkinson’s disease, and it helps doctors make a diagnosis and follow the progression of the condition. Rigidity refers to a type of hypertonia, which involves increased resistance to movement. However, unlike other types of hypertonia, rigidity is not direction- or velocity-dependent. This means that there is the same amount of resistance regardless of whether a person bends or extends the affected limb and that the speed of motion does not affect muscle tone. In people with cogwheel rigidity, the limbs move with small jerky, or ratchet-like, movements. Alongside difficulty moving, stiffness from any type of rigidity may also cause pain and discomfort. Testing Doctors can test a person for cogwheel rigidity. During a rigidity test, a doctor will ask a person to relax the muscles in their limbs. Then, the doctor will flex and extend the person’s limb. They will assess whether the muscles are stiff or inflexible while they are trying to move the limb and whether it moves with small ratcheting motions. Ratcheting motions and spastic movements are distinct signs of cogwheel rigidity, and they are both potential signs of Parkinson’s disease. The earlier a doctor is able to diagnose Parkinson’s disease, the quicker a person’s treatment can begin. Cogwheel rigidity vs lead pipe rigidity Lead pipe rigidity describes a different type of rigidity that a person may experience with Parkinson’s disease. Unlike cogwheel rigidity, where it feels as though the limb is catching on the teeth of gears, lead pipe rigidity consists of steady and smooth resistance throughout the entire range of motion. Its name comes from the fact that moving the limb feels similar to bending a lead pipe. Causes The most common cause of cogwheel rigidity is Parkinson’s disease. However, these signs of rigidity may also occur in other Parkinsonian conditions, such as:progressive supranuclear palsycorticobasal syndromemultiple system atrophy Movement-related symptoms of Parkinson’s typically occur due to neurons in an area of the brain known as the substantia nigra — which plays a critical role in movement — becoming damaged or dying. Experts refer to neurons in the substantia nigra as dopaminergic. This means that they are responsible for producing dopamine, which is an important neurotransmitter for movement. Low levels of dopamine may affect nerve firing patterns, which can result in movement problems. Research indicates that most people with PD lose roughly 60–80% of dopamine-producing cells in the substantia nigra by the time they notice symptoms. If neurons in the substantia nigra do not produce enough dopamine, a person will likely begin to experience movement-related problems, such as cogwheel rigidity. Learn more about the causes of tight and rigid muscles. Treatment Although there is currently no cure for Parkinson’s disease, some treatments may help improve symptoms of the condition. For example, a doctor may prescribe medications such as carbidopa and levodopa tablets. These are often the most effective treatment option for Parkinson’s disease. A person with Parkinson’s disease may also wish to consider doing some types of exercise that may help manage rigidity, bradykinesia, and balance problems. These can include:doing aerobic exercisestretching regularlypracticing yoga or tai chibouncing a ball to keep moving the armspracticing techniques to reduce stress, as it may worsen Parkinson’s symptoms A person with Parkinson’s disease can consult a physical therapist to find out what exercise is likely to work best for them. Learn more about the treatment options for Parkinson’s disease. Other Parkinson s symptoms A person with Parkinson’s disease may also experience symptoms other than rigidity. Other physical symptoms may include:slow or difficult movementtremorsbalance problemsloss of sense of smellconstipationproblems with urinatingerectile dysfunction in malessexual dysfunction in femalesdizzinesschanges in sweatinginsomniaswallowing difficultiesdry skin Mental symptoms may include:depressionanxietymild cognitive impairmentdementia Summary Cogwheel rigidity refers to a ratchet-like movement that is a common sign of Parkinson’s disease. This movement disorder may cause discomfort as well as stiffness. Alongside rigidity, common movement-related symptoms include tremors, slow movements, and balance problems. These signs and symptoms can help doctors diagnose and monitor Parkinson’s disease. Last medically reviewed on September 27, 2022Parkinson's DiseaseNeurology / Neuroscience 17 sourcescollapsedMedical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.Approach to the exam for Parkinson's disease. (n.d.). https://stanfordmedicine25.stanford.edu/the25/parkinsondisease.htmlCogwheel rigidity. (n.d.). https://dictionary.apa.org/cogwheel-rigidityCogwheel rigidity. (n.d.). https://www.ncbi.nlm.nih.gov/medgen/57469Conditions that mimic Parkinson's. (n.d.). https://www.parkinson.org/Understanding-Parkinsons/Diagnosis/Conditions-that-Mimic-ParkinsonsFearon, C., et al. (2015). How do I examine rigidity and spasticity? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6183506/Hypertonia. (2022). https://www.ninds.nih.gov/health-information/disorders/hypertoniaLabel: Carbidopa and levodopa tablet. (2022). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=33fbe430-b429-43c0-a3f1-9cf016ff23afNoblesala, E. (2016). Five ways to help muscle stiffness in Parkinson's disease. https://www.michaeljfox.org/news/five-ways-help-muscle-stiffness-parkinsons-diseaseParkinson's disease. (2022). https://www.ninds.nih.gov/Disorders/All-Disorders/Parkinsons-Disease-Information-PageParkinson's disease: Causes, symptoms, and treatments. (2022). https://www.nia.nih.gov/health/parkinsons-diseaseParkinson's disease: Hope through research. (2022). https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Hope-Through-Research/Parkinsons-Disease-Hope-Through-ResearchParkinson's disease. (n.d.). https://lsom.uthscsa.edu/neurosurgery/clinical-practice/parkinsons-disease/Parkinson's disease: Overview. (2019). https://www.nhs.uk/conditions/parkinsons-disease/Rigidity and Parkinson's: What it is and how to treat it. (2020). https://davisphinneyfoundation.org/rigidity-and-parkinsons-what-it-is-and-how-to-treat-it/Rigidity. (n.d.). https://www.parkinson.org/understanding-parkinsons/symptoms/movement-symptoms/rigiditySonne, J., et al. (2021). Neuroanatomy, substantia nigra. https://www.ncbi.nlm.nih.gov/books/NBK536995/Sonne, J., et al. (2022). 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