Classification of disturbance of consciousness

Classification of depression of consciousness and coma

There are various classifications of disorders of consciousness.

N.K. Bogolepov, one of the creators who described comatose states in the most detail ("Comatose States", 1962), distinguishes 4 degrees of coma: mild, severe, deep and terminal. This division is based primarily on the assessment of the degree of inhibition of the activity of the cortical, subcortical and stem parts of the brain. F. Plum and J. Posner in the classic monograph "The Diagnosis of Stupor and Coma" ("Diagnosis of Stupor and Coma", 1986) avoid any division of coma by the degree of inhibition of brain function, believing that this complicates the diagnosis of the level and nature of damage. Based on the main questions facing the doctor when examining a comatose patient: "Functional or organic damage", "Local or diffuse damage", "Cause of coma", "Dynamics of the state", the authors propose dividing comatose states into the following main categories:

• caused by supratentorial volumetric lesions that have a secondary effect on the deep diencephalic-brainstem structures;
• caused by subtentorial destructive or compressive processes;
• metabolic disorders leading to widespread suppression or cessation of functioning of both supra- and subtentorial structures;
• psychogenic states resembling coma.

In the classification proposed by A.R. Shakhnovich (1988), the degree of depression of consciousness is determined based on a combination of the most informative signs, depending on the functional state of both supra- and subtentorial structures (answers to questions, orientation, execution of instructions, opening the eyes in response to sound or pain, bilateral mydriasis, oculocephalic reflex, muscle atony). The informativeness of the signs is expressed quantitatively. According to this classification, disturbances of consciousness are subdivided into moderate, deep stunning, apallic state, coma, deep coma and extreme coma. A similar three-stage division of the comatose state is characteristic of other classifications (Konovalov A.N. et al., 1982). The designation of essentially similar comatose states may be different [moderate, deep, terminal (atonic) coma; coma I, II, III]. In recent decades, one of the most common classifications of depression of consciousness has become the Glasgow Coma Scale (1974). The scale is based on a total score of 3 functions: speech, movement, and eye opening. It allows a doctor or medical worker of any specialty to quickly determine the severity of the patient's condition.

Glasgow Coma Scale

Opening the eyes

• Arbitrary - 4.
• For spoken word - 3.
• To pain stimulus - 2.
• Missing -1.

Motor reaction

• Executes commands - 6.
• Targeted at the pain stimulus - 5.
• Not directed at the pain stimulus - 4.
• Tonic flexion to a painful stimulus - 3.
• Tonic extension to a painful stimulus - 2.
• Missing - 1.

Verbal function (in the absence of intubation)

• Oriented and able to maintain a conversation - 5.
• Disoriented, can speak - 4.
• Incoherent speech - 3.
• Slurred speech - 2.
• Missing - 1.

Verbal function (during intubation)

• Probably able to speak - 3.
• Questionable ability to speak - 2.
• No reaction - 1.

The proposed scoring system relates to the descriptive classifications approximately as follows:

• 15 points - clear consciousness;
• 14-13 points - moderate stunning;
• 12-10 points - deep stunning;
• 9-8 points - stupor;
• 7 or less - comatose states.

Classifications of impaired consciousness allow us to judge to a certain extent the extent and level of brain damage and to justify the prognosis of the disease. Coming out of a coma (moderate coma, coma I) is possible, and normal brain function can be fully restored. Deep coma (coma II) often ends in death or transition to a chronic condition. Extreme coma (atonic, coma III) is almost always irreversible.

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