dissociation

1. Separation, or a dissolution of relations. SYN: disassociation. 2. The change of a complex chemical compound into a simpler one by any lytic reaction, by ionization, by heterolysis, or by homolysis. 3. An unconscious separation of a group of mental processes from the rest, resulting in an independent functioning of these processes and a loss of the usual associations; for example, a separation of affect from cognition. See multiple personality. 4. A state used as an essential part of a technique for healing in psychology and psychotherapy, for instance in hypnotherapy or the neurolinguistic programming technique of time-line therapy. SEE ALSO: Time-Line therapy. 5. The translocation between a large chromosome and a small supernumerary one. 6. Separation of the nuclear components of a heterokaryotic dikaryon. [L. dis-socio, pp. -atus, to disjoin, separate, fr. socius, partner, ally]

- albuminocytologic d. increased protein in the cerebrospinal fluid without increase in cell count, characteristic of the Guillain-Barré syndrome; it is also associated with spinal block and with intracranial neoplasia, and is seen in the last phases of poliomyelitis.

- atrial d. mutually independent beating of the two atria or of parts of the atria.

- atrioventricular d. (AVD), AV d. 1. any situation in which atria and ventricles are activated and contract independently, as in complete AV block; 2. more specifically, the d. between atria and ventricles that results from slowing of the atrial pacemaker or acceleration of the ventricular pacemaker at nearly equal (rarely equal) rates, each depolarizing its own chamber, thus interfering with depolarization by the other (interference-d.).

- complete atrioventricular d., complete AV d. aV d. not interrupted by ventricular captures. SYN: complete AV block (2), third degree AV block.

- electromechanical d. persistence of electrical activity in the heart without associated mechanical contraction; often a sign of cardiac rupture. SYN: pulseless electrical activity.

- incomplete atrioventricular d., incomplete AV d. aV d. interrupted by ventricular captures.

- interference d. the simultaneous operation of two separate cardiac pacemaking foci that are unassociated because of interference (a normal physiologic phenomenon) due to rendering their respective territories refractory to each other. Usually atrioventricular d. is indicated, the rates being quite close to each other with the atrial rate slightly slower than that of the pacemaker in control of the ventricles. Capture is in either direction, usually the ventricle by the atrium, in incomplete d.. h SYN: d. by interference.

- d. by interference SYN: interference d..

- isorhythmic d. AV d. characterized by equal or closely similar atrial and ventricular rates.

- light-near d. SYN: pupillary light-near d..

- longitudinal d. d. between parallel chambers of the heart, as between one atrium and the other or between one ventricle and the other, in contrast to d. between atria and ventricles.

- pupillary light-near d. pupillary light-near d..

- sleep d. SYN: sleep paralysis.

- syringomyelic d. loss of pain and temperature sensation with relative retention of tactile sensation, related to a cavity in the central portion of the cord interrupting the decussation of nerve fibers.

- tabetic d. loss of proprioceptive sensation with retained pain and temperature sensation due to involvement of the posterior columns of the spinal cord.

- visual-kinetic d. the neurolinguistic programming process of removing a synesthesia from a person's internal experience. SEE ALSO: neurolinguistic programming.

* * *

dis·so·ci·a·tion (.)dis-.ō-sē-'ā-shən, -shē- n

1) the act or process of dissociating: the state of being dissociated: as

a) the process by which a chemical combination breaks up into simpler constituents esp one that results from the action of energy (as heat) on a gas or of a solvent on a dissolved substance

b) the separation of whole segments of the personality (as in multiple personality disorder) or of discrete mental processes (as in the schizophrenias) from the mainstream of consciousness or of behavior with loss of integrated awareness and autonomous functioning of the separated segments or parts

2) the process by which some biological stocks (as of certain bacteria) differentiate into two or more distinct and relatively permanent strains also such a strain

* * *

n.

(in psychiatry) the process whereby thoughts and ideas can be split off from consciousness and may function independently, thus (for example) allowing conflicting opinions to be held at the same time about the same object. Dissociation may be the main factor in cases of dissociative fugue and multiple personalities.

* * *

dis·so·ci·a·tion (dĭ-so″se-aґshən) [dis-¹ + sociatio union] 1. the act of separating or state of being separated. 2. the separation of a molecule into two or more fragments (atoms, molecules, ions, or free radicals) produced by the absorption of light or thermal energy or by solvation. 3. segregation of a group of mental processes from the rest of a person's usually integrated functions of consciousness, memory, perception, and sensory and motor behavior, as in the separation of the personality and aspects of memory or subpersonalities in the dissociative disorders (q.v.) or in the segregation of an idea or object from its emotional significance, as is sometimes seen in schizophrenia. dissociative adj