Persistent vegetative state

A state of wakeful unawareness.

Diagnostic criteria: 1) no evidence of awareness of themselves or their environment, incapable of interacting with others, 2) no evidence of sustained, reproducible purposeful, or voluntary behavioral responses to visual, auditory, tactile or noxious stimuli, 3) no evidence of language comprehension or expression, 4) intermittent wakefulness with sleep-wake cycles, 5) sufficient hypothalamic and brainstem autonomic function to survive if given nursing and medical care, 6) bowel and bladder incontinence, and 7) variably preserved cranial nerve and spinal reflexes.

Diagnosis is typically made after 1 month of impaired consciousness.

The term permanent vegetative state is reserved for those with a certain irreversible state applied after 12 months.

Patients usually require minimal hemodynamic support.

Eyes may open wide when touched, but visual pursuit is absent or brief and is not reproducible.

Visual orientating reflex may occur, but persistent visual scanning, tracking or optokinetic nystagmus does not occur.

When large objects are presented, such as a person, the patient may briefly turn their eyes and suggest focusing, but it is not sustained.

Eyes typically rove back and forth but do not fixate.

Blinking to threat is rare response.

May respond to sound with a startle but consistent looking toward the origin of the sound does not occur.

Pain causes no response or grimacing and can be associated with tachycardia, tachypnea and pathologic limb flexion or extension.

Moving or touching the patient may cause change in facial expression.

Eliciting snout, glabella, palmo-mental and corneomandibular reflexes is easily achieved.

In some this is permanent process, while in others eventually signs of awareness appear but patients remain unable to communicate interactively-this is ref2242ed to as a minimally conscious state.

In a study of 54 patient’s with disorders of consciousness in patients in a vegetative or minimally conscious state MRI was utilized to assess patient’s ability to generate willful, neuroanatomic specific, blood oxygen level dependent responses during 2 mental imagery tasks: 5 patients were able to willfully modulate their brain activity, indicating a small number of patients in the above impaired conscious states have brain activation reflecting some awareness and cognition (Martin MM).

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