Glossary
B
Baclofen:
Surgical destruction or removal of tissue, an organ, or a precise region of a particular structure. Ablation may involve surgical cutting (excision); chemical destruction, such as injection of phenol; or the use of high-frequency electrical current or radio waves. For example, pallidotomy is a procedure used in the treatment of Parkinson’s disease or certain other movement disorders. The procedure involves surgical ablation of part of the internal portion of the globus pallidus (GPi)–i.e., a brain region involved in regulating movement–in an attempt to “rebalance” movement and posture control. Once a wire probe is inserted into and precisely positioned within the GPi, it heats and destroys adjacent tissue through the emission of radio waves.
An abnormal neuromuscular condition that is generally considered a severe form of chorea. Involvement of the upper muscles of the arms and legs results in uncontrolled, violent, flinging or throwing actions. These swinging or jerky movements may be sporadic or continuous and, in some patients, restricted to one side of the body (hemiballismus). Ballismus often occurs in association with other abnormal involuntary movements, including athetosis, chorea, and dystonia.
Ballismus:
Basal ganglia:
Specialized nerve cell clusters of gray matter deep within each cerebral hemisphere and the upper brainstem, including the striate body (caudate and lentiform nuclei) and other cells groups such as the subthalamic nucleus and substantia nigra. The basal ganglia assist in initiating and regulating movement.
Benign myoclonus of infancy:
A neurologic condition that typically becomes apparent by approximately 4 months of age. Affected infants and children experience relatively short, mild episodes of myoclonus, or sudden, involuntary, “shock-like” spasms of muscles, particularly of the head, neck, trunk, and arms. Development is typically normal, and myoclonus usually ceases by age 2 or 3.
Benzodiazepines:
A class of medications that act upon the central nervous system to reduce communication between certain neurons, lowering the level of activity in the brain. Benzodiazepines are effective in reducing anxiety, stress, or agitation; promoting sleep; alleviating restlessness; and relaxing muscles.
Beta-adrenergic receptor:
a specialized molecular structure on the surface membrane of a neuron that selectively receives the neurotransmitter norepinephrine. Reception of this neurotransmitter causes changes in the neuron that increase its likelihood of “firing” or sending its own signal to other neurons. The activities of norepinephrine affect that part of the nervous system involved in the control of some involuntary body functions, such as blood pressure regulation, etc. (sympathetic nervous system).
Bilateral:
Having or affecting two sides.
Biosynthesize:
To form or produce (during normal physiologic functions) a chemical compound in the body.
Biphasic:
having two distinct stages or phases.
Body mass index:
The body mass index is a measure of body fat that is based on a person’s height and weight.
Botulinum toxin (BTX):
Any of a group of toxins, designated as A through G, produced by Clostridium botulinum bacteria. Localized injection of minute amounts of commercially prepared BTX may help to relax an overactive muscle by blocking the release of acetylcholine, a neurotransmitter responsible for the activation of muscle contractions. BTX-A is currently the only form (i.e., serotype) of botulinum toxin approved for clinical use. (BTX-A [BOTOX®] is produced by Allergan, Inc. and used in the United States and many other countries. Outside the U.S., it is available as Dysport® from Ipsen, Ltd.) It was originally introduced in the 1970s for the treatment of misalignment of the eyes (strabismus) and involuntary contraction of eyelid muscles (blepharospasm) associated with dystonia or facial nerve disorders. BTX-A is now increasingly being used as a therapeutic option for selected patients with other disorders characterized by severely increased muscle activity (hyperactivity), such as tremor, other focal dystonias, and spasticity. BTX-B is currently under investigation (by Athena Neurosciences, Inc.) for patients with cervical dystonia.
Bradykinesia:
The gradual loss of spontaneous movement; slowness of voluntary movements.
Brainstem:
The region of the brain consisting of the medulla oblongata, pons, and midbrain. The brainstem primarily contains white matter interspersed with some gray matter. This area of the brain serves as a two-way conduction path, conveying nerve impulses between other brain regions and the spinal cord. In addition, most of the 12 pairs of cranial nerves from the brain arise from the brainstem, regulating breathing, digestion, heartbeat, blood pressure, pupil size, swallowing, and other basic functions.
Branched-chain amino acids:
the essential amino acids, isoleucine, leucine, and valine.
Bruxism:
Involuntary grinding, clenching, or gnashing of the teeth, particularly during sleep or times of stress. Without appropriate protection, such as the use of night guards that cover the teeth, severe dental problems may result. Bruxism may also be a feature of certain neurologic movement disorders, including dystonia of the jaw, mouth, and lower face (oromandibular dystonia [OMD]), Rett syndrome, or tardive dyskinesia.
Burke-Fahn-Marsden
Dystonia Rating Scale (BFMDRS):
The BFMDRS is a weighted scale that measures the severity and provoking factors for dystonia in 9 body areas, including the eyes, mouth, speech or swallowing, neck, right and left arms, trunk, and right and left legs.