Prolonged Disorders of Consciousness A Wake Up Call

Prolonged Disorders of Consciousness A Wake Up Call

Consciousness • No clear agreed definition by neuroscientists • Generally accepted 2 components – Wakefulness – Awareness

Neural Basis of Consciousness Reticular activating system in brain stem Cerebral cortex Thalamus AWAKE AWARE

Cerebral cortex Thalamus Cerebellum Brain stem Spinal cord

Normal Cortex: working AWARE Reticular activating system : working AWAKE

Neural Basis of Consciousness Reticular activating system STATE AWAKE Cerebral cortex Thalamus CONTENT • sensations • emotions • images • memories • Ideas etc. AWARE

Disturbance of consciousness

Common terms • Sleep: a state of reduced responsiveness to, and interaction with, the environment which is readily reversible • Confusional state: minor disorientation, faulty memory, short attention span, some difficulty following commands • Delirium: disorientation, irritability, restlessness, hallucinations • Stupor: unresponsive & only aroused by vigorous stimulation • Coma: unresponsive & unrousable

Glasgow Coma Scale • • Eye Opening 4 = spontaneous 3= to verbal command 2= to pain 1= none to pain Verbal Response 5 = orientated to time & place 4 = confused: talking in sentences but disorientated 3 = words: utters occasional words rather than sentences 2 = sounds: grunts & groans 1 = none • Motor Response 6 = Obeys commands 5 = Localises to pain 4 = Flexion withdrawal 3= Abnormal flexion 2 = Extends to pain 1 = none

Definition of Coma • A state of unrousable psychological unresponsiveness in which subject lies with eyes closed & shows no response to external stimulus or inner need • GCS: at best E 2; M 4; V 2 (no eye opening to voice; weak flexion to pain; grunt to pain)

Prolonged disorders of consciousness after severe brain damage • Vegetative state • Minimally conscious state • Locked in syndrome • Brain stem death

Consciousness Being consciousness requires a person to be awake and aware. To be both, the reticular activating system and the cerebral cortex ( & thalamus) need to be intact.

Normal Cortex: working AWARE Reticular activating system : working AWAKE

Vegetative State • A clinical condition of unawareness of self & environment • Usually the patient – breathes spontaneously – has a stable circulation – shows cycles of eye closure & opening (simulating sleep & waking. )

Vegetative state Cortex: NOT working UNAWARE Reticular activating system : working AWAKE

Vegetative State [European : Unresponsive Wakefulness Syndrome(UWS) ; apallic syndrome] Usually: • Breathe spontaneously • Stable circulation • Cycles of eye closure/opening (like sleep/wake)

Observed Behaviours during VEGETATIVE STATE • • • Chewing; teeth grinding; tongue pumping Roving eye movements Non-purposeful limb movements Facial movements (e. g. smiles or grimaces) Shedding tears Grunts or groans

Prevalence of VS • Estimate: 0. 5 -2/100, 000 • Thus: – ~26 -106 cases in Scotland – ~6 -24 cases in Greater Glasgow & Clyde NHS – ~4 -16 cases in Lothian NHS

Minimally Conscious State One or more of following – follows simple commands – gestural or verbal yes/no responses – intelligible verbalization – stereotypical movements (e. g. blink, smile) in meaningful relationship to the eliciting stimulus & not reflexive – manipulation of objects

Minimally Conscious State(MCS) Crying, smiling, laughing in response to emotional stimuli Vocalisation or gestures to comments/questions Reaching for objects Touching/holding objects in a manner that accommodates the size & shape of object • Sustained fixation or pursuit eye movements in direct response to stimuli • Other localising or discriminating behaviours that constitute: • • – Movement towards a perceived object – Differential responses to different objects or people

Emergence from MCS Responses become RELIABLE & CONSISTENT • Functional Communication: verbal, written , using augmentative communication device ; or yes/no signals. +/or • Functional use of objects: discrimination between at least 2 different objects

Assessment tools • JFK Coma Recovery Scale-Revised (CRS-R) • Wessex Head Injury Matrix (WHIM) • Sensory Modality Assessment and Rehabilitation Technique (SMART) • Western Neuro Sensory Stimulation Profile (WNSSP) • Sensory Stimulation Assessment Measure (SSAM) • Disorders of Consciousness Scale (DOCS)

Investigative techniques • Functional MRI (f. MRI) scans • Electrophysiology – Sleep EEG – Evoked potentials

Treatment approaches • Medications: – Amantadine – Zolpidem – Methylphenidate • Neurostimulation: – Deep brain stimulation – Transcranial magnetic stimulation – Transcranial direct current stimulation • Sensory stimulation (Coma arousal programmes)

Deep brain stimulation (DBS)

Transcranial magnetic stimulation(TMS)

Transcranial direct current stimulation(t. DCS)

Prognosis in VS & MCS • Likelihood of functional improvement diminishes over time • Shorter window for recovery in non-TBI cf. TBI (e. g. VS : 3 mths non-TBI; 12 mths TBI) • MCS ~70% emerge by 2 yrs. ; ~30% by 4 yrs post-injury

Permanent Vegetative State • > 6 months after non-traumatic brain injury • > 1 year after traumatic brain injury

Care Pathway (RCP) ITU/ Neurosurgery Assessment by N-rehab team at 4 days Hospital ward Neurorehabilitation Specialist Nursing Home 24 hour care programme Medical management of complications Assessment of responses Best interests meeting 3 -4 months Formal review : Non-TBI 6 mths. TBI 1 year MCS annually for 5 years

Neurorehabilitation 24 hour programme • Airway • Nutrition & hydration • Oral care • Bowel & bladder • Pressure care • Positioning/stretching • Supportive seating Medical management • Hydrocephalus • Diabetes insipidus • Epilepsy • Spasticity • Pain • Intercurrent infection • Deep vein thrombosis prevention

Neurorehabilitation (Cont. ) • Assessment of responses • Family communication re: diagnosis & prognosis • Best interest meeting – Resuscitation – Use of antibiotics etc. • Discharge planning

Care Pathway (RCP) ITU/ Neurosurgery Assessment by N-rehab team at 4 days Hospital ward Neurorehabilitation 24 hour care programme Medical management of complications Assessment of responses Best interests meeting 3 -4 months Specialist Nursing Home Long term care Formal review : Non-TBI 6 mths. TBI 1 year MCS annually for 5 years

Locked-in Syndrome • • • Consciousness intact Can open eyes & move up & down Total limb paralysis No speech (anarthria) Difficulty swallowing (dysphagia) • GCS: E 4, M 1, V 1

Locked in syndrome Cortex: working AWARE Reticular activating system: working BUT!! AWAKE Ventral pons damaged: quadriplegia

Brainstem Cerebellum MIDBRAIN PONS IVth ventricle MEDULLA

Locked in Syndrome Vertical eye movements Cardiovascular & Respiratory Centres VENTRAL PONS Motor pathways to limbs & trunk Reticular Activating System

Cause & Mechanism Cause Mechanism Ischaemic Basilar artery occlusion; hypotension/hypoxia Haemorrhage in pons Trauma Contusion; vertebrobasilar dissection Tumour Infiltration of ventral pons Metabolic Central pontine myelinolysis Demyelination Multiple sclerosis Infection Brain stem encephalitis; abscess

Brain stem death 1. Irremediable brain damage of known cause 2. Deep coma: effects of drugs & potentially reversible metabolic/endocrine disturbances excluded 3. Ventilator dependent

Brain stem death Nothing working including respiratory, vasomotor centre etc

Brain stem death Brainstem reflexes • No pupil response to light • No corneal reflex • No vestibulo-ocular reflex • No cranial motor response to pain • No gag reflex or response to suction • Loss of doll’s head eye movements Brainstem death • Unconscious • No cyclical eye opening • No motor function other than reflex spinal • GCS: E 1, M 1 -2, V 1 • Switch off ventilator for 3 -5 minutes: no respiration

NORMAL LOCKED IN SYNDROME VEGETATIVE STATE BRAIN STEM DEATH