Motor neuron diseases or motor neurone diseases (MNDs) are a group of rare neurodegenerative disorders that selectively affect motor neurons, the cells which control voluntary muscles of the body. They include amyotrophic lateral sclerosis (ALS), progressive bulbar palsy (PBP), pseudobulbar palsy, progressive muscular atrophy (PMA), primary lateral sclerosis (PLS), spinal muscular atrophy (SMA) and monomelic amyotrophy (MMA), as well as some rarer variants resembling ALS.
A nerve is an enclosed, cable-like bundle of nerve fibers in the peripheral nervous system.
Transverse myelitis (TM) is a rare neurological condition wherein the spinal cord is inflamed. The adjective transverse implies that the spinal inflammation (myelitis) extends horizontally throughout the cross section of the spinal cord; the terms partial transverse myelitis and partial myelitis are sometimes used to specify inflammation that affects only part of the width of the spinal cord. TM is characterized by weakness and numbness of the limbs, deficits in sensation and motor skills, dysfunctional urethral and anal sphincter activities, and dysfunction of the autonomic nervous system that can lead to episodes of low blood pressure and Dizziness. Signs and symptoms vary according to the affected level of the spinal cord. The underlying cause of TM is unknown. The spinal cord inflammation seen in TM has been associated with various infections, immune system disorders, or damage to nerve fibers, by loss of myelin. As opposed to leukomyelitis which affects only the white matter, it affects the entire cross-section of the spinal cord. Decreased electrical conductivity in the nervous system can result.
Spasticity is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity, and hypertonia. It is also colloquially referred to as an unusual "tightness", stiffness, or "pull" of muscles.
Myelitis is inflammation of the spinal cord which can disrupt the normal responses from the brain to the rest of the body, and from the rest of the body to the brain. Inflammation in the spinal cord can cause the myelin and axon to be damaged resulting in symptoms such as paralysis and sensory loss. Myelitis is classified to several categories depending on the area or the cause of the lesion; however, any inflammatory attack on the spinal cord is often referred to as transverse myelitis.
The somatic nervous system (SNS) is made up of nerves that link the brain and spinal cord to voluntary or skeletal muscles that are under conscious control as well as to skin sensory receptors. Specialized nerve fiber ends called sensory receptors are responsible for detecting information within and outside of the body.
Paresthesia is an abnormal sensation of the skin with no apparent physical cause. Paresthesia may be transient or chronic, and may have many possible underlying causes. Paresthesias are usually painless and can occur anywhere on the body, but most commonly occur in the arms and legs.
Mucopolysaccharidoses are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal enzymes needed to break down molecules called glycosaminoglycans (GAGs). These long chains of sugar carbohydrates occur within the cells that help build bone, cartilage, tendons, corneas, skin and connective tissue. GAGs are also found in the fluids that lubricate joints.
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. It belongs to the hyperkinetic movement disorders, among tremor and chorea for example. 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.
Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness.
Foot drop is a gait abnormality in which the dropping of the forefoot happens due to weakness, irritation or damage to the deep fibular nerve, including the sciatic nerve, or paralysis of the muscles in the anterior portion of the lower leg. It is usually a symptom of a greater problem, not a disease in itself. Foot drop is characterized by inability or impaired ability to raise the toes or raise the foot from the ankle (dorsiflexion). Foot drop may be temporary or permanent, depending on the extent of muscle weakness or paralysis and it can occur in one or both feet. In walking, the raised leg is slightly bent at the knee to prevent the foot from dragging along the ground.
Progressive bulbar palsy (PBP) is a medical condition. It belongs to a group of disorders known as motor neuron diseases. PBP is a disease that attacks the nerves supplying the bulbar muscles. These disorders are characterized by the degeneration of motor neurons in the cerebral cortex, spinal cord, brain stem, and pyramidal tracts. This specifically involves the glossopharyngeal nerve (IX), vagus nerve (X), and hypoglossal nerve (XII).
Group C nerve fibers are one of three classes of nerve fiber in the central nervous system (CNS) and peripheral nervous system (PNS). The C group fibers are unmyelinated and have a small diameter and low conduction velocity, whereas Groups A and B are myelinated. Group C fibers include postganglionic fibers in the autonomic nervous system (ANS), and nerve fibers at the dorsal roots. These fibers carry sensory information.
Pallesthesia, or vibratory sensation, is the ability to perceive vibration. This sensation, often conducted through skin and bone, is usually generated by mechanoreceptors such as Pacinian corpuscles, Merkel disk receptors, and tactile corpuscles. All of these receptors stimulate an action potential in afferent nerves found in various layers of the skin and body. The afferent neuron travels to the spinal column and then to the brain where the information is processed. Damage to the peripheral nervous system or central nervous system can result in a decline or loss of pallesthesia.
Central nervous system diseases or central nervous system disorders are a group of neurological disorders that affect the structure or function of the brain or spinal cord, which collectively form the central nervous system (CNS). These disorders may be caused by such things as infection, injury, blood clots, age related degeneration, cancer, autoimmune disfunction, and birth defects. The symptoms vary widely, as do the treatments.
Nervous system diseases, also known as nervous system or neurological disorders, refers to a small class of medical conditions affecting the nervous system. This category encompasses over 600 different conditions, including genetic disorders, infections, cancer, seizure disorders, conditions with a cardiovascular origin, congenital and developmental disorders, and degenerative disorders.
Myelomalacia is a pathological term referring to the softening of the spinal cord. Possible causes of myelomalacia include cervical myelopathy, hemorrhagic infarction, or acute injury, such as that caused by intervertebral disc extrusion.
Cervicocranial syndrome or is a neurological illness. It is a combination of symptoms that are caused by an abnormality in the neck. The bones of the neck that are affected are cervical vertebrae (C1-C7). This syndrome can be identified by confirming cervical bone shifts, collapsed cervical bones or misalignment of the cervical bone leading to improper functioning of cervical spinal nerves. Cervicocranial syndrome is either congenital or acquired. Some examples of diseases that could result in cervicocranial syndrome are Chiari disease, Klippel-Feil malformation osteoarthritis, and trauma. Treatment options include neck braces, pain medication and surgery. The quality of life for individuals suffering from CCJ syndrome can improve through surgery.
Neurogenic bowel dysfunction (NBD) is the inability to control defecation due to a deterioration of or injury to the nervous system, resulting in faecal incontinence or constipation. It is common in people with spinal cord injury (SCI), multiple sclerosis (MS) or spina bifida.
Peripheral mononeuropathy is a nerve related disease where a single nerve, that is used to transport messages from the brain to the peripheral body, is diseased or damaged. Peripheral neuropathy is a general term that indicates any disorder of the peripheral nervous system. The name of the disorder itself can be broken down in order to understand this better; peripheral: in regard to peripheral neuropathy, refers to outside of the brain and spinal cord; neuro: means nerve related; -pathy; means disease. Peripheral mononeuropathy is a disorder that links to Peripheral Neuropathy, as it only effects a single peripheral nerve rather than several damaged or diseased nerves throughout the body. Healthy peripheral nerves are able to “carry messages from the brain and spinal cord to muscles, organs, and other body tissues”.
