Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements, that indicates dysfunction of parts of the nervous system that coordinate movement, such as the cerebellum. These nervous system dysfunctions occur in several different patterns, with different results and different possible causes. Ataxia can be limited to one side of the body, which is referred to as hemiataxia. Friedreich's ataxia has gait abnormality as the most commonly presented symptom. Dystaxia is a mild degree of ataxia.
Cerebellar hypoplasia is characterized by reduced cerebellar volume, even though cerebellar shape is (near) normal. It consists of a heterogeneous group of disorders of cerebellar maldevelopment presenting as early-onset non–progressive congenital ataxia, hypotonia and motor learning disability.
Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectively occur with the muscles that help produce speech, often making it very difficult to pronounce words. It is unrelated to problems with understanding language, although a person can have both. Any of the speech subsystems can be affected, leading to impairments in intelligibility, audibility, naturalness, and efficiency of vocal communication. Dysarthria that has progressed to a total loss of speech is referred to as anarthria. The term dysarthria is from New Latin, dys- "dysfunctional, impaired" and arthr- "joint, vocal articulation".
Olivopontocerebellar atrophy (OPCA) is the degeneration of neurons in specific areas of the brain – the cerebellum, pons, and inferior olivary nucleus. OPCA is present in several neurodegenerative syndromes, including inherited and non-inherited forms of ataxia and multiple system atrophy (MSA), with which it is primarily associated.
The inferior olivary nucleus (ION), is a structure found in the medulla oblongata underneath the superior olivary nucleus. In vertebrates, the ION is known to coordinate signals from the spinal cord to the cerebellum to regulate motor coordination and learning. These connections have been shown to be tightly associated, as degeneration of either the cerebellum or the ION results in degeneration of the other.
Friedreich's ataxia is an autosomal-recessive genetic disease that causes difficulty walking, a loss of sensation in the arms and legs, and impaired speech that worsens over time. Symptoms generally start between 5 and 20 years of age. Many develop hypertrophic cardiomyopathy and require a mobility aid such as a cane, walker, or wheelchair in their teens. As the disease progresses, some affected people lose their sight and hearing. Other complications may include scoliosis and diabetes mellitus.
Spinocerebellar ataxia (SCA) is a progressive, degenerative, genetic disease with multiple types, each of which could be considered a neurological condition in its own right. An estimated 150,000 people in the United States have a diagnosis of spinocerebellar ataxia at any given time. SCA is hereditary, progressive, degenerative, and often fatal. There is no known effective treatment or cure. SCA can affect anyone of any age. The disease is caused by either a recessive or dominant gene. In many cases people are not aware that they carry a relevant gene until they have children who begin to show signs of having the disorder.
Purkinje cells, or Purkinje neurons, are a class of GABAergic inhibitory neurons located in the cerebellum. They are named after their discoverer, Czech anatomist Jan Evangelista Purkyně, who characterized the cells in 1839.
Dysmetria is a lack of coordination of movement typified by the undershoot or overshoot of intended position with the hand, arm, leg, or eye. It is a type of ataxia. It can also include an inability to judge distance or scale.
The flocculus is a small lobe of the cerebellum at the posterior border of the middle cerebellar peduncle anterior to the biventer lobule. Like other parts of the cerebellum, the flocculus is involved in motor control. It is an essential part of the vestibulo-ocular reflex, and aids in the learning of basic motor skills in the brain.
Cerebellar ataxia is a form of ataxia originating in the cerebellum. Non-progressive congenital ataxia (NPCA) is a classical presentation of cerebral ataxias.
Intention tremor is a dyskinetic disorder characterized by a broad, coarse, and low frequency tremor evident during deliberate and visually-guided movement. An intention tremor is usually perpendicular to the direction of movement. When experiencing an intention tremor, one often overshoots or undershoots one's target, a condition known as dysmetria. Intention tremor is the result of dysfunction of the cerebellum, particularly on the same side as the tremor in the lateral zone, which controls visually guided movements. Depending on the location of cerebellar damage, these tremors can be either unilateral or bilateral.
Journal Citation Reports (JCR) is an annual publication by Clarivate. It has been integrated with the Web of Science and is accessed from the Web of Science Core Collection. It provides information about academic journals in the natural and social sciences, including impact factors. The JCR was originally published as a part of the Science Citation Index. Currently, the JCR, as a distinct service, is based on citations compiled from the Science Citation Index Expanded and the Social Sciences Citation Index. As of the 2023 edition, journals from the Arts and Humanities Citation Index and the Emerging Sources Citation Index will also be included.
Uner Tan syndrome (UTS) is a syndrome that was discovered by the Turkish evolutionary biologist Üner Tan. People affected by UTS walk with a quadrupedal locomotion and often have severe learning disabilities. Tan postulated that this is an example of "reverse evolution" (atavism). The proposed syndrome was featured in the 2006 BBC2 documentary The Family That Walks On All Fours.
Benedikt syndrome, also called Benedikt's syndrome or paramedian midbrain syndrome, is a rare type of posterior circulation stroke of the brain, with a range of neurological symptoms affecting the midbrain, cerebellum and other related structures.
Dyschronometria is a condition of cerebellar dysfunction in which an individual cannot accurately estimate the amount of time that has passed. It is associated with cerebellar ataxia, when the cerebellum has been damaged and does not function to its fullest ability. Lesions to the cerebellum can cause dyssynergia, dysmetria, dysdiadochokinesia, dysarthria, and ataxia of stance and gait. Dyschronometria can result from autosomal dominant cerebellar ataxia (ADCA).
Mihai Ioan Botez was born in Ploiești, Romania, trained at Carol Davila University of Medicine and Pharmacy, a neurologist and academic who specialized in the field of neuropsychology. He immigrated to Montreal in the 1970s, becoming a professor at the Université de Montréal and director of the department of Neurology at the hospital Hôtel-Dieu de Montréal.
Post-viral cerebellar ataxia also known as acute cerebellitis and acute cerebellar ataxia (ACA) is a disease characterized by the sudden onset of ataxia following a viral infection. The disease affects the function or structure of the cerebellum region in the brain.
Autosomal recessive cerebellar ataxia type 1 (ARCA1) is a condition characterized by progressive problems with movement. Signs and symptoms of the disorder first appear in early to mid-adulthood. People with this condition initially experience impaired speech (dysarthria), problems with coordination and balance (ataxia), or both. They may also have difficulty with movements that involve judging distance or scale (dysmetria). Other features of ARCA1 include abnormal eye movements (nystagmus) and problems following the movements of objects with their eyes. The movement problems are slowly progressive, often resulting in the need for a cane, walker, or wheelchair.
Megan Carey is a neuroscientist and Group Leader of the Neural Circuits and Behavior Laboratory at the Champalimaud Centre for the Unknown in Lisbon, Portugal. She is known for her work on how the cerebellum controls coordinated movement.
