rashmi thimmapuram presentation

Rashmi Thimmapuram

Illinois Mathematics and Science Academy

Repeated and unpredictable seizures

Varying intensities of seizures

Treatment Options

Medical treatment

Resection Surgery

Evaluation

Magnetic Resonance Imaging (MRI) or Computed

Tomography (CT)

Intracranial Monitoring using Electrocorticography

(ECoG) and Electrocoritcal Stimulation Mapping (ESM)

Electrocorticography (ECoG)

Used to monitor cerebral activity

Power vs. Time graph

Electrodes implanted subdurally

Electrode Grids and Size

Electrode Grid Implantation

Functions correspond to regions

Brain reorganization in epileptic patients

Brain Mapping – Relationship between function and

anatomy of brain

Electrocortical Stimulation Mapping (ESM)

Direct electric stimulation of the cortex

“Gold Standard”

Drawbacks

Invasive

Tedious and time consuming

Risk of unnatural seizures

Language Region

Broca’s Area - speaking

Wernicke’s Area – listening

Language Task

Listens to and repeats words

Identified language region in previous

investigations (Towle et al. 2008)

Used for comparison

Suitable format

Purpose

The purpose of this experiment is to find a less tedious

and more patient-friendly way to localize language region

Focusing question

"Can the Electrocorticography (ECoG) captured while the patient is

conversing with staff/visitors during the hospital stay be used to

localize language region?"

Hypothesis

ECoG during Natural Conversation will localize the

language region

Language task localized language region

Patient’s video recordings

Video Player

Patient’s ECoG data

PC with MS-Windows &

Ubuntu

Computer Applications

EEGvue

Neuroscan 4.3

Loc3D Jr.

EEG View

MS-Excel

Neuroscan

Loc3D Jr.

Independent Variable Type of method used to localize the language region

Dependent Variable Brain activation (µV)

Constants Patient

Single hospital stay

Electrode grid

Frequency band range

Lobes observed

Comparison Group

Language task

Overview of localization of language region using Natural Conversation

Timestamps for different states from the videos

EEG Vue

Neuroscan 4.3

1 Continuous file for Listening

Neuroscan ASCII Data fileLoc3D Jr

Transpose using

MS-Excel

NeuroscanASCII Data file

CT Scan parameters

INFO file

Electrode Marker File

CSV FileEEG View

1 Continuous file for Talking

1 Continuous file for Resting

1 Continuous file for Listening

Only

1 Continuous file for Talking

Only

Electrode Spatial location

CSV file

Specific electrodesAMP file

REG file

Brain modelVTK file

ECoG data

Epoch FileEpoch FileEpoch FileEpoch FileAverage File

Epoch FileEpoch FileEpoch FileEpoch FileCContinuous File

Nicolet BMSI file containing the EEG

segment<patient>.<state>.<da

te>.<cd#>.<trial#>

Epoch FileEpoch FileEpoch FileEpoch FileEpoch File

CT Scans

Operational definitions for each state

Talking

Listening

Resting

ECoG segments from patient’s videos

Load and position data

Compare and contrast brain activation

CD # Date CD Start CD End Event Start Event End State Duration29 7/27/2004 22:44:48 23:24:21 23:10:26 23:10:43 Listening to Conversation 0:00:17

29 7/27/2004 22:44:48 23:24:21 23:11:52 23:11:55 Listening to Conversation 0:00:03

29 7/27/2004 22:44:48 23:24:21 23:12:45 23:12:53 Talking 0:00:08

29 7/27/2004 22:44:48 23:24:21 23:12:58 23:13:10 Talking 0:00:12

28 7/27/2004 22:05:15 22:44:48 22:20:15 22:20:20 Talking 0:00:05



28 7/27/2004 22:05:15 22:44:48 22:25:18 22:25:25 Talking (w/ hand) 0:00:07

28 7/27/2004 22:05:15 22:44:48 22:25:28 22:25:33 Talking (w/ hand) 0:00:05

28 7/27/2004 22:05:15 22:44:48 22:26:49 22:26:51 Talking 0:00:02

27 7/27/2004 21:25:42 22:05:15 22:01:21 22:01:26 Resting (eyes closed) 0:00:05



27 7/27/2004 21:25:42 22:05:15 22:03:04 22:03:13 Talking 0:00:09

27 7/27/2004 21:25:42 22:05:15 22:03:38 22:03:53 Talking (w/ hand) 0:00:15

27 7/27/2004 21:25:42 22:05:15 22:04:03 22:04:08 Talking 0:00:05

27 7/27/2004 21:25:42 22:05:15 22:04:18 22:04:23 Talking 0:00:05


25 7/27/2004 20:06:36 20:46:09 20:14:06 20:14:22 Resting (eyes open) 0:00:16










18 7/27/2004 15:29:45 16:09:18 15:30:30 15:30:32 Talking 0:00:02

18 7/27/2004 15:29:45 16:09:18 15:30:35 15:30:38 Talking 0:00:03

18 7/27/2004 15:29:45 16:09:18 15:31:05 15:31:20 Talking 0:00:15







16 7/27/2004 14:10:39 14:50:12 14:11:11 14:11:20 Talking 0:00:09


The highlighted times are the samples that were averaged and used for comparison. Some

identified samples were not used for multiple reasons. Either they were too short or the patient

was performing another action such as moving his or her hand while talking or listening.

Patient Activity Log

Example of Power Spectrum

(Frequency vs. Power)

Power Spectra of all electrodes in

talking after resting was removed

Natural Conversation Language Task

Electrode Activation (Natural Conversation vs. Language Task)

Grid Location Electrode #Natural

ConversationLanguage task

Frontal Grid

33 X -

40 - X

44 - X

45 - X

46 - X

53 X X

Parietal/Upper

Temporal Grid

78 X -

79 - X

80 X X

83 X X

84 X -

88 X -

91 X -

92 X -

95 X X

96 X X

Note: ‘X’ in the column indicates Electrode Activation. ‘–‘ indicates absence of

Electrode Activation. Highlighted in orange are the electrodes that were activated

in both Natural Conversation and Language task.

Hypothesis not supported

Natural conversation could not localize the same

language region that language task did

However, natural conversation activated more regions in

parietal grid

Not ready for clinical applications

Can be used alongside ESM to refine the

technique

Future work

Automated mapping (Ziegler et al. 2011)

Wireless data transmission

Software automation

Difficult to find test subjects

Lateralization of brain function

Right handed with left side grids/left handed with right

side grids

Lack of video-ECoG recordings

Debate over definition of language

Various levels (Poeppel et al. 2012)

I would like to thank…

Dr. Vernon Leo Towle, University of Chicago

Falcon Dai & Weili Zheng, University of Chicago

Dr. Judith Scheppler & SIR Department, Illinois

Mathematics and Science Academy

Parents

Bauer P., Vansteensel M., Bleichner M., Hermes D., Ferrier C., Aarnoutse E., & Ramsey N (2013). Mismatch between electrocortical

stimulation and Electrocorticography frequency mapping of language. Brain Stimulation. xxx:1-8.

Borchers S., Himmelbach M., Logothetis N., & Karnath H. (2012). Direct electrical stimulation of human cortex- the gold standard for

mapping brain functions? Nat. Rev. Neurosci. 13:63-70.

Carter R., Aldridge S., Page M., & Parker S. (2009). The Human Brain Book: An illustrated guide to its structure, functions, and

disorders. New York, NY: DK Publishing.

Crone N., Sinai A., Korzeniewska A. (2006). High-frequency gamma oscillations and human brain mapping with electrocorticography.

Prog. Brain Res. 159:275-95.

"Epilepsy". Fact Sheets. World Health Organization. October 2012.

<http://www.who.int/mediacentre/factsheets/fs999/en/index.html> Accessed 24 Jul. 2013.

Gaona C.M., Sharma M., Freudenburg Z.V., Breshears J.D., Bundy D.T., Roland J., Barbour D.L., Schalk G., & Leuthardt E.C. (2011).

Nonuniform high-gamma (60–500 Hz) power changes dissociate cognitive task and anatomy in human cortex. J. Neurosci. 31:2091–2100.

Geschwind N. (1970). The Organization of Language and the Brain. Science. 170:940-944.

Penfield W. (1958). Some mechanisms of consciousness discovered during electrical stimulation of the brain. Proceedings of the National

Academy of Sciences of the United States of America. 44(2):51-56

Poeppel D., Emmorey K., Hickok G., & Pylkkanen L. (2012). Towards a new neurobiology of language. J. Neurosci. 32(41):14125-14131.

Ruescher J., Iljina O., Altenmuller D., Aertsen A., Schulze-Bonhage A., & Ball T. (2013). Somatotopic mapping of natural upper- and

lower-extremity movements and speech production with high gamma Electrocorticography. NeruoImage. 81:164-177.

Sinai A., Bowers C.W., Crainiceanu C.M., Boatman D., Gordon B., Lesser R.P., Lenz F.A., & Crone N.E. (2005). Electrocorticographic high

gamma activity versus electrical cortical stimulation mapping of naming. Brain. 128:1556-1570.

Towle V., Yoon H., Castelle M., Edgar J.C., Biassou N.M., Frim D., Spire J., & Kohrman M. (2008). ECoG gamma activity during a

language task: differentiating expressive and receptive speech areas. Brain. 131:2013-27.

Watkins K. & Paus T. (2004). Modulation of Motor Excitability during Speech perception: The Role of Broca’s Area. Journal of Cognitive

Neuroscience. 16(6):978-987.

Wu M.,Wisneski K., Schalk G., Sharma M., Roland J., Breshears J., Gaona C., Leuthardt E.C. (2010). Electrocorticographic frequency

alteration mapping for extraoperative localization of speech cortex. Neurosurgery 66:407–409.

Ziegler J., Kretzschmar H., Stachniss C., Grisetti G., & Burgard W. (2011). Accurate human motion capture in large areas by combining

IMU- and laser-based people tracking. Intelligent Robots and Systems (IROS). 86–91.

http://www.who.int/mediacentre/factsheets/fs999/en/index.html

rashmi thimmapuram presentation

Documents

patients brain

brain waves

brain disorder

brain activity

individuals brain

electrocorticography

epileptic regions

temporal lobe