Predictors of Better Outcomes After Severe Acquired Brain Injuries

Clinical, Neurophysiological and Genetical Predictors of Consciousness Recovery and Functional Outcomes After Severe Acquired Brain Injuries

Severe Acquired Brain Injury is defined as a traumatic, post-anoxic, vascular or other brain damage that causes coma for at least 24 hours and leads to permanent disability with sensorial, motor, cognitive or compartmental impairment. In this context, an accurate characterization of individual patients' profile in terms of neuronal damage, potential for neuroplasticity, neurofunctional and clinical state could allow to plan tailored rehabilitation and care pathway on the basis of solid prognostic information, also for optimizing resources of the National Health care systems and enhance ethical decisions. Patient profiling should encompass measures and procedures easily available at the bedside, and with affordable time, resource, and money-costs to determine a real impact on National Health systems. The aim of the study is identifying patient profiles in terms of clinical, neurophysiological and genetical aspects with better long-term outcome in order to plan tailored therapeutic interventions.

Background:

After a severe Acquired Brain Injury (sABI) the consciousness, the functional and the cognitive recovery of the patients depends on the severity of the damage suffered but also on the vulnerability of the individual brain. Some patients with sABI may survive in a state of Disorder of Consciousness (DoC) condition (i.e., patients in vegetative state/unresponsive wakefulness syndrome, VS/UWS or in minimally conscious state, MCS). Other patients, despite having a complete recovery of consciousness, can reach very variable degrees of functional and cognitive autonomy. The prognostic factors of consciousness recovery of patients with DoCs have been thoroughly investigated. Most of these studies investigated the acute phase, while only a few studies have examined the role of early clinical factors emerging before the complete recovery of consciousness . Further prognostic insights can be provided by analysis of genes coding for Apolipoprotein E (APOE), dopamineD2 receptor (DRD2), and Brain Derived Neutrophic Factors (BDNF), and by markers of axonal injury.

Study aim:

The present project aims at identifying patient profiles with better long-term outcome in order to plan tailored therapeutic interventions.

The patient profiles will be drawn up by gathering patient's demographic (age, gender, social and educational level), anamnestic (aetiology and time post-brain injury, Cognitive Reserve Index), clinical state (Cumulative Illness Rating Scale (CIRS), CRS-R total score and corresponding consciousness state; Disability Rating Scale, DRS, Functional Oral Intake Scale; FOIS, Glasgow Outcome Scale Expanded; GOS-E, Level of Cognitive Functioning; LCF) and neurophysiological data (Electroencephalogram (EEG), Somatosensory evoked potentials (SEP), and Motor evoked potentials (MEP) nerve conduction aimed at evaluating occurrence of critical illness polyneuropathy and myopathy (CIPNM)) at study entry (baseline), together with neural biomarkers (genetic markers).

On the basis of the above mentioned stratification of patients by this multimodal approach, the present study aimed to

1. Investigate the possible association of certain profiles with the consciousness recovery at the time of discharge from the Intensive Rehabilitation Unit (IRU), at 1 year and 2 years from the acute event
2. Investigate the possible association of certain profiles with the functional outcomes at the time of discharge from the Intensive Rehabilitation Unit (IRU), at 1 year and 2 years from the acute event.
3. Investigate the possible association of certain profiles with the long-term cognitive profile and the level of familiar and social participation at 1 year and 2 years from the acute event.

Setting , population and methods:

The proposed study is a longitudinal multi-location prospective observational cohort study.

Four centers of the Don Carlo Gnocchi Foundation will participate (Florence, La Spezia, Milan and Sant'Angelo dei Lombardi and the neurogenetics laboratory of the University of Florence, Department of Medical and Experimental Sciences, Neurology). The enrollment phase will last 3 years (June 2020-June 2023). 520 patients with severe brain injury will be included (200 for the Florence and La Spezia units and 60 for the Milan and Sant'Angelo dei Lombardi units).

All patients admitted in the participant IRU with a history of sABI within 4 months, aged 18+, presenting a signed informed consent signature for the participation to the study and for the genetic analysis will be consecutively enrolled.

A multidimodal evaluation including clinical examinations and neurophysiological assessments will be performed by skilled professionals. The study foresees four steps in the late acute phase and two in the long-term phase: 1) at the study entry time (T0), 2) at three months from T0 (T1) 3) at 6 months from T0 (T2) 4) at discharge (T3) 5) at 12 months from the acute event (T4) 6) at 24 months from the acute event.

Clinical assessment including :

1. Consciousness assessment using CRS-R
2. Care severity profile: including the comorbidity assessed thought the Cumulative Illness Rating Scale (CIRS), the presence of medical devices, sepsis occurrence during the IRU stay, neurosurgery interventions, bedsores, epileptic event and other complications
3. Functional evaluation using the following scales: ERBI, GOS-E, DRS, FIM, PAINED pain scale, TCT, Ashworth, FOIS
4. Neurocognitive profile evaluation using the Galveston Orientation and Amnesia Test (GOAT), the Level of Cognitive Functioning (LCF) and the International Classification of Functioning, Disability and Health (ICF), ABS, AES and Cognitive Reserve Index (CRI)

Multimodal neurophysiological evaluation including:

1. Standard EEG recording at rest. EEG background activity and reactivity will be classified according to recently proposed diagnostic criteria for DoC and to American Clinical Neurophysiology Society Critical Care EEG Terminology.
2. Motor and sensory nerve conduction studies. Sensory nerve action potentials, and compound muscle action potentials (CMAP) will be evaluated. Muscular activity at rest and when possible during reflex contraction will be assessed.
3. PEM: Transcranial magnetic stimulation (TMS) will be performed according to the standard criteria of the International Federation of Clinical Neurophysiology. MEP will be recorded from abductor digiti minimi and tibialis anterior muscles and size of MEP measured as MEP/CMAP amplitude ratio.
4. Bilateral upper limb SEP will be recorded according to the International Federation of Clinical Neurophysiology. The presence or absence of N20/P25 cortical components will be evaluated.

Genetic assessment Genomic DNA will be obtained from EDTA-whole venous blood sample by Automated Systems QiaCube (Qiagen). The genetic analysis of 5 different single nucleotide polymorphisms on ApoE, BDNF and DRD2 genes will be performed by high resolution melt (HRM) analyses and direct sequencing on Automatic Genetic Analyzer. APOE genotypes will be investigated by HRM with two sets of PCR primers designed to amplify the regions encompassing rs7412 [NC_000019.9: g.45412079C>T] and rs429358 (NC_000019.9: g.45411941T>C). The samples with known ApoE genotypes, which had been validated by DNA sequencing, will be used as standard references. The genetic polymorphism data will be compared to sex- and age-matched control of the DNA banking of the neurogenetic Laboratory of Careggi Hospital of Florence.

Statistic analysis:

All collected data will be analyzed using a machine learning algorithm, creating, for each patient, a risk profile for the possible consciousness recovery and functional autonomy.

On the basis of the results of this study, partecipant will build on a "decision support tool" for future sABI patients afferent to the Intensive Rehabilitative Unit, in order to plan personalized rehabilitative and therapeutic interventions, allowing therefore an optimization of resources (costs and resources) for National Health Service

Inclusion Criteria:

• patients admitted with a history of severe Acquired Brain Injury within 4 months,
• aged 18+,
• signed informed consent signature for the participation to the study
• signed informed consent signature for the participation to for the genetic analysis

Exclusion Criteria:

• patients admitted with a history of severe Acquired Brain Injury more then 4 months
• Absence of informed consent to participate in the study