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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.
A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. The person may experience respiratory and circulatory problems due to the body's inability to maintain normal bodily functions. People in a coma often require extensive medical care to maintain their health and prevent complications such as pneumonia or blood clots. Coma patients exhibit a complete absence of wakefulness and are unable to consciously feel, speak or move. Comas can be derived by natural causes, or can be medically induced.
Brain death is the permanent, irreversible, and complete loss of brain function which may include cessation of involuntary activity necessary to sustain life. It differs from persistent vegetative state, in which the person is alive and some autonomic functions remain. It is also distinct from comas as long as some brain and bodily activity and function remain, and it is also not the same as the condition locked-in syndrome. A differential diagnosis can medically distinguish these differing conditions.
The plantar reflex is a reflex elicited when the sole of the foot is stimulated with a blunt instrument. The reflex can take one of two forms. In healthy adults, the plantar reflex causes a downward response of the hallux (flexion). An upward response (extension) of the hallux is known as the Babinski response or Babinski sign, named after the neurologist Joseph Babinski. The presence of the Babinski sign can identify disease of the spinal cord and brain in adults, and also exists as a primitive reflex in infants.
A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not mohamed amr pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain. The brain will receive the input while the reflex is being carried out and the analysis of the signal takes place after the reflex action.
Myoclonus is a brief, involuntary, irregular twitching of a muscle, a joint, or a group of muscles, different from clonus, which is rhythmic or regular. Myoclonus describes a medical sign and, generally, is not a diagnosis of a disease. These myoclonic twitches, jerks, or seizures are usually caused by sudden muscle contractions or brief lapses of contraction. The most common circumstance under which they occur is while falling asleep. Myoclonic jerks occur in healthy people and are experienced occasionally by everyone. However, when they appear with more persistence and become more widespread they can be a sign of various neurological disorders. Hiccups are a kind of myoclonic jerk specifically affecting the diaphragm. When a spasm is caused by another person it is known as a provoked spasm. Shuddering attacks in babies fall in this category.
Václav Vojta was a renowned Czech medical doctor who specialized in the treatment of children with cerebral palsy and developmental disorders. He discovered the principle of reflex locomotion, which is used to treat various physical and neuromuscular disorders through the stimulation of the human sensomotoric system's reflex points. Originally used in the treatment of spastic children, the technique is now used on babies and adults.
Hyperkinesia refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both. Hyperkinesia is a state of excessive restlessness which is featured in a large variety of disorders that affect the ability to control motor movement, such as Huntington's disease. It is the opposite of hypokinesia, which refers to decreased bodily movement, as commonly manifested in Parkinson's disease.
Hemiballismus or hemiballism is a basal ganglia syndrome resulting from damage to the subthalamic nucleus in the basal ganglia. Hemiballismus is a rare hyperkinetic movement disorder, that is characterized by violent involuntary limb movements, on one side of the body, and can cause significant disability. Ballismus affects both sides of the body and is much rarer. Symptoms can decrease during sleep.
Abnormal posturing is an involuntary flexion or extension of the arms and legs, indicating severe brain injury. It occurs when one set of muscles becomes incapacitated while the opposing set is not, and an external stimulus such as pain causes the working set of muscles to contract. The posturing may also occur without a stimulus. Since posturing is an important indicator of the amount of damage that has occurred to the brain, it is used by medical professionals to measure the severity of a coma with the Glasgow Coma Scale and the Pediatric Glasgow Coma Scale.
The vestibulospinal tract is a neural tract in the central nervous system. Specifically, it is a component of the extrapyramidal system and is classified as a component of the medial pathway. Like other descending motor pathways, the vestibulospinal fibers of the tract relay information from nuclei to motor neurons. The vestibular nuclei receive information through the vestibulocochlear nerve about changes in the orientation of the head. The nuclei relay motor commands through the vestibulospinal tract. The function of these motor commands is to alter muscle tone, extend, and change the position of the limbs and head with the goal of supporting posture and maintaining balance of the body and head.
Focal neurologic signs also known as focal neurological deficits or focal CNS signs are impairments of nerve, spinal cord, or brain function that affects a specific region of the body, e.g. weakness in the left arm, the right leg, paresis, or plegia.
Clasp-knife response refers to a Golgi tendon reflex with a rapid decrease in resistance when attempting to flex a joint, usually during a neurological examination. It is one of the characteristic responses of an upper motor neuron lesion. It gets its name from the resemblance between the motion of the limb and the sudden closing of a claspknife after sufficient pressure is applied.
Blocq's disease was first considered by Paul Blocq (1860–1896), who described this phenomenon as the loss of memory of specialized movements causing the inability to maintain an upright posture, despite normal function of the legs in the bed. The patient is able to stand up, but as soon as the feet are on the ground, the patient cannot hold himself upright nor walk; however when lying down, the subject conserved the integrity of muscular force and the precision of movements of the lower limbs. The motivation of this study came when a fellow student Georges Marinesco (1864) and Paul published a case of parkinsonian tremor (1893) due to a tumor located in the substantia nigra.
A beating heart cadaver is a body that is pronounced dead in all medical and legal definitions, connected to a medical ventilator, and retains cardio-pulmonary functions. This keeps the organs of the body, including the heart, functioning and alive. As a result, the period of time in which the organs may be used for transplantation is extended. The heart contains pacemaker cells that will cause it to continue beating even when a patient is brain-dead. Other organs in the body do not have this capability and need the brain to be functioning to send signals to the organs to carry out their functions. A beating heart cadaver requires a ventilator to provide oxygen to its blood, but the heart will continue to beat on its own even in the absence of brain activity. This allows organs to be preserved for a longer period of time in the case of a transplant or donation. A small number of cases in recent years indicate that it can also be implemented for a brain-dead pregnant woman to reach the full term of her pregnancy. There is an advantage to beating heart cadaver organ donation because doctors are able to see the vitals of the organs and tell if they are stable and functioning before transplanting to an ailing patient. This is not possible in a donation from someone pronounced dead.
Brainstem death is a clinical syndrome defined by the absence of reflexes with pathways through the brainstem – the "stalk" of the brain, which connects the spinal cord to the mid-brain, cerebellum and cerebral hemispheres – in a deeply comatose, ventilator-dependent patient. Identification of this state carries a very grave prognosis for survival; cessation of heartbeat often occurs within a few days, although it may continue for weeks if intensive support is maintained.
Babinski–Nageotte syndrome is an alternating brainstem syndrome. It occurs when there is damage to the dorsolateral or posterior lateral medulla oblongata, likely syphilitic in origin. Hence it is also called the alternating medulla oblongata syndrome.
Disorders of consciousness are medical conditions that inhibit consciousness. Some define disorders of consciousness as any change from complete self-awareness to inhibited or absent self-awareness and arousal. This category generally includes minimally conscious state and persistent vegetative state, but sometimes also includes the less severe locked-in syndrome and more severe but rare chronic coma. Differential diagnosis of these disorders is an active area of biomedical research. Finally, brain death results in an irreversible disruption of consciousness. While other conditions may cause a moderate deterioration or transient interruption of consciousness, they are not included in this category.
Cutaneous, superficial, or skin reflexes, are activated by skin receptors and play a valuable role in locomotion, providing quick responses to unexpected environmental challenges. They have been shown to be important in responses to obstacles or stumbling, in preparing for visually challenging terrain, and for assistance in making adjustments when instability is introduced. In addition to the role in normal locomotion, cutaneous reflexes are being studied for their potential in enhancing rehabilitation therapy (physiotherapy) for people with gait abnormalities.
Sunil Pradhan is an Indian neurologist, medical researcher and writer, known for the invention of two electrophysiological techniques. He has also described five medical signs, of which one related to Duchenne muscular dystrophy is known as Pradhan Sign, and the others associated with facioscapulohumeral muscular dystrophy (FSHD) and similar neuro diseases. The Government of India awarded him the Padma Shri, the fourth highest civilian award, in 2014 for his contributions to the field of neuroscience.
References
- ↑ "Brain death and brainstem failure". The Egyptian Society of Medical Ethics. 2009. Archived from the original on June 5, 2014. Retrieved August 26, 2011.
- 1 2 S.G Han; et al. (2006). "Reflex Movements in Patients with Brain Death: A Prospective Study in A Tertiary Medical Center". Journal of Korean Medical Science. 21 (3): 588–90. doi:10.3346/jkms.2006.21.3.588. ISSN 1011-8934. PMC 2729975 . PMID 16778413.
- 1 2 3 4 Allan H Ropper (1984). "Unusual spontaneous movements in brain-dead patients". Neurology. 34 (8): 1089–90. doi:10.1212/wnl.34.8.1089. PMID 6540387. S2CID 2351431. Archived from the original on 2018-08-10. Retrieved 2009-07-12.
- 1 2 3 Calixto Machado (2007). Brain death: a reappraisal. Springer. p. 79. ISBN 978-0-387-38975-2.
- ↑ "Practice Parameters: Determining Brain Death in Adults" (PDF). American Academy of Neurology. 1994. Archived from the original (PDF) on 6 February 2009. Retrieved 12 July 2009.
