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EVENT-RELATED BRAIN POTENTIALS IN PATIENTS WITH BRAIN INJURY

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TH

30 INTERNATIONAL CONGRESS OF CLINICAL NEUROPHYSIOLOGY (ICCN) OF THE IFCN

EVENT-RELATED BRAIN POTENTIALS IN PATIENTS WITH BRAIN INJURY

Objetive: Evoked potentials are used up 20 years in comatose patients in

order to assess brain function and awakening prognosis. Recently Evoked Potentials Related Events (ERP) has been used in coma for identifying patients in minimally conscious state.

The main objective of this study is clarify the correlation between the patterns of ERP and levels of physical and cognitive disabilities due to brain injury. We use the classical paradigm of "oddball" and assessing the degree of disability by Glasgow Outcome Scale (GOS).

Methods: ERP, a standard “oddball” paradigm and auditory evoked

potentials, early responses (BERA) were recorded in 23 normal and 46 brain injuried patients. The Glasgow Outcome Scale was determined concurrently with the P300 ERP.

Results: GOS: Good Recovery 7/46 (15%), Moderate Disability 9/46

(20%), Severe Disability 18/46 (39%) and Vegetative State 12/46 (26%). P3b to desviant was found in 25/46 patients. P3a to desviant was found in 6 patients .We were observed a higher incidence of absence of the N2 10/12 and alteration of BERA 7/12 in vegetative state . Twenty percent (20%) of the Vegetative Status patient 2/12 had P300a ERP.

Conclusion:The ERP is useful in the evaluation of patients with brain injury

in order to investigate the level of awareness . The absent of N2 strongly describe a vegetative state.

Evoked potentials are used up 20 years in comatose patients in order to

assess brain function and awakening prognosis. The main objective of this

study is to clarify the correlation between the patterns of ERP and levels of

physical and cognitive disabilities due to brain injury.

A cross-sectional study was performed in patients with Stroke or Traumatic Brain Injury to estimate ERP and its association with the Glasgow Outcome Scale from March 1,2013 to September 10, 2013. The ERP was assessed 1 year after brain injury ( 1 month-9 years).

A typical P300 paradigm comprises a rapidly sequence of the oddball paradigm. If the participant was unable to perform the task, a passive oddball

7 was done to elicit P3a .

A montage for recording P300 include Cz and Pz scalp locations. Common reference was the ear lobe.

The scalp location where P300 was of maximum amplitude is used to measure latency.

3

Luauté J et al (2005) indicate the presence of the N200 potential and

good prognosis for return to consciousness after awakening from coma.

Our study did not confirm those data. Our results point to the absence of

the N200 component and the presence of vegetative state, the small

number of patients analyzed in the present study may explain the

conflicting results.

4

Fischer et al (2008) indicate the presence of potential P3A and good

cognitive performance upon awakening from a coma, our results point to

the presence of P3B indicating better cognitive performance. The

discrepancy in both results are probably due to the difference of the type of

patients studied.

ABSTRACT

RESULTS

INTRODUCTION

METHODOLOGY

DISCUSSION

Figure 1 AML, male, 17 years old, Traumatic brain injury.

ERP recorded 45 days after injury. Vegetative state. ERP potentials not observed.

Figure 2 SM, male, 76 years old, Stroke . ERP recorded

9 years after last stroke. Aphasic, right side hemiplegic. The patient doesn´t respond to commands.

Figure 3 VAD, female, 33 years old. Stroke. ERP

recorded 60 days after stroke. Vegetative state. P300a was observed.

Figura 4 MS , male , 53 years old. Stroke. ERP recorded

30 days after stroke. Aphasic, The patient doesn´t respond to commands. N1/P2 was observed but P3.

RESULTS

TABLE 1 - Glasgow Outcome Scale in the

46 patients

TABLE 2 - Latencies of P3B and P3A at the

two midline electrodes Cz,Pz vs Etiology

The ERP is useful in the evaluation of patients with brain injury in order to

5

investigate the levels of awareness .

The ERP identifies cases of minimal level of awareness among patients

who are clinically in Vegetative State, helping the team to a

multidisciplinary approach.

The interpretation of results must be treated carefully from the point of

6

view of good results as in his absence .

1. Fischer C et al. Mismatch negativity and late auditory evoked potentials in comatose patients. Clin Neurophysiol 1999;1601-10.

2. Jennet B,Bond M. Assessment of outcome after severe brain damage. Lancet 1975:1(7905):480-4

3. Luauté J et al. Late Auditory and Event-related Potentials can be useful fo predict good functional outcome after coma. Arch Phys Med Rehabil 2005;86:917-23

4. Fischer C, Dailler F, Morlet D. Novelty P3 elicited by the subjects´s own name in comatose patients. Clin Neurophysiol 2008;2224-230. 5. Perrin F et al. Brain Response to One´s Own Nane in Vegetative State, Minimally Conscious Satae, and Locked-in Syndrome. Arch Neurol 2006;63:562-69

6. Kotchoubey B, Lang S, Bostanov V, Birbaumer N. Is there a Mind? Electrophysiology of Unconscious Patients. News Physiol Sci 2002;17:38-42

7. Duncan C C at al. Event-related potentials in clinical research: Guidelines for eliciting, recording, and quantifying mismatch, P300, and N400.Clin Neurophysiol 2009;1883-908.

CONCLUSION

REFERENCES

CENTRO DE REABILITAÇÃO E READAPTAÇÃO

DR. HENRIQUE SANTILLO

Angela Maria Costa de Souza¹, Fernanda Vieira Moraes¹, Mara Lucia Carneiro Guimaraes¹, Victor Frak².

1. REHABILITATION AND READAPTATION CENTER (CRER) NEUROPHYSIOLOGY DEPARTMENT - GOIANIA, GO, BRAZIL

2. UQAM - FACULTY OF SCIENCE - CANADA

7 8 1 10 4 2 1 1 2 2 6 2 0 2 4 6 8 10 12 P3 B P3 A N200 + N200 - N1/P2

-GLASGOW OUTCOME SCALE VS ERP

Good Recovery Moderately Diseable Severely Diseable Vegetative State P > 0,05 _ _

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