Characterization of Long-term Continuous Electrodermal
Activity Lateralization in Pediatric Epilepsy Patients
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Citation
Poh, M. Z., et al. "Characterization of Long-Term Continuous
Electrodermal Activity Lateralization in Pediatric Epilepsy
Patients." in Abstracts from the 2009 Annual Meeting of the
American Epilepsy Society. Epilepsia, 50(Suppl. 11):11-12, 2009
As Published
http://dx.doi.org/10.1111/j.1528-1167.2009.02377.x
Publisher
Wiley-Blackwell
Version
Original manuscript
Accessed
Thu May 26 20:24:34 EDT 2016
Citable Link
http://hdl.handle.net/1721.1/57433
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Attribution-Noncommercial-Share Alike 3.0 Unported
Detailed Terms
http://creativecommons.org/licenses/by-nc-sa/3.0/
63rd Annual Meeting of the American Epilepsy Society
Boston, MA, USA
December 4-8, 2009
Characterization of Long-term Continuous Electrodermal Activity Lateralization in
Pediatric Epilepsy Patients
Ming-Zher Poh1,2, Tobias Loddenkemper, MD3, Nicholas C. Swenson2, Mangwe C. Sabtala2,
Joseph R. Madsen, MD4, Rosalind W. Picard, ScD2.
1Harvard-MIT
Division of Health Sciences and Technology, Cambridge, MA, United States, 02139; 2The
Media Laboratory, Massachusetts Institute of Technology, Cambridge, MA, United States, 02139; 3Division
of Epilepsy and Clinical Neurophysiology, Department of Neurology, Children's Hospital Boston, Boston, MA,
United States, 02115 and 4Neurosurgery, Children's Hospital Boston, Boston, MA, United States, 02115.
RATIONALE: Electrodermal activity (EDA) reflects sympathetic activation within the autonomic
nervous system. Activity within prefrontal cortices and limbic structures strongly influence
ipsilateral EDA (Critchley HD Neuroscientist 2002;8:132-42). This relationship suggests that
unilateral dysfunction of cortical activity may affect the direction of EDA lateralization. We
hypothesized that hemispheric location of seizure onset in patients with epilepsy may be related
to ipsilaterally increased sympathetic skin response as evidenced by EDA asymmetry.
METHODS: EDA of 22 patients undergoing long-term video/EEG monitoring were recorded
continuously from the ventral side of bilateral distal forearms using custom-built skin conductance
sensors for 1-4 days. EDA recordings were lowpass filtered (1024 points, Hamming window,
cutoff 0.016 Hz) to obtain skin conductance levels (SCL). Right/left differences were calculated in
order to determine fR>L, the frequency of right-sided EDA lateralization (R > L), fL>R, the frequency
of left-sided EDA lateralization (L > R) and fR=L, the frequency of EDA symmetry (R = L).
Differences less than 0.05 µS were considered as R = L. The frequency of right/left EDA
lateralization was compared within patients with a right (n = 6) and left-sided (n = 12) irritative
zone or seizure onset zone respectively. To examine the role of handedness on EDA
lateralization, the frequency of right/left EDA lateralization was also compared within both right (n
= 13) and left-handed (n = 3) patients (handedness of 2 patients was unknown). Statistics were
computed with MATLAB using the Wilcoxon rank sum test.
RESULTS: 18 patients (11 males, 7 females) between ages 4-20 years with unilateral irritative
zone or unilateral seizure onset on scalp EEG as determined by long-term video/EEG monitoring
were included. 13 patients were right-handed, 3 were left-handed, and in 2 handedness was
undetermined. There were 12 and 6 patients with a left and right-sided ictal onset/irritative zone
respectively. For patients with a left-sided seizure onset zone or irritative zone, the mean fR>L
(0.43 ± 0.23) was not significantly different from the mean fL>R (0.46 ± 0.23). However, for patients
with a right-sided seizure onset, the mean fR>L (0.58 ± 0.22) was higher than the mean fL>R (0.28 ±
0.20) (p < 0.05). Neither right nor left-handed patients nor patients with right or left MRI lesions
displayed significantly different frequency of right/left EDA lateralization.
CONCLUSIONS: We present the first characterization of lateralization in long-term continuous
bilateral EDA in patients with epilepsy. Our pilot series suggests a relationship between
hemispheric location of seizure onset/irritative zone and EDA lateralization. Frequency of right/left
EDA lateralization may potentially provide additional lateralizing information regarding seizure
onset zone or irritative zone on EEG in the presurgical assessment of epilepsy patients. Further
studies regarding localizing and lateralizing value are currently underway.
Epilepsia (2009)
Table 1. Clinical characteristics and recorded data of patients with epilepsy
Case
Sex
1
Age
(yrs)
4
F
Handedness
Rt.
MRI findings
2
14
M
Rt.
Lt. temporal lobe
cortical dysplasia
Normal
3
6
F
Rt.
Normal
4
9
M
Lt.
5
6
7
7
6
9
M
M
M
Lt.
Lt.
-
8
9
14
18
F
M
Rt.
Rt.
10
11
12
9
6
10
F
M
F
Lt.
Lt.
13
10
F
Rt.
14
20
M
Rt.
15
9
M
Rt.
16
17
18
15
14
5
M
F
M
Rt.
Rt.
-
Lt. temporal lobe
cortical dysplasia
Lt. MCA infarct
Lt. MCA infarct
Lt. cerebellar
hemisphere volume loss
Normal
Lt. precentral sulcus
cortical malformation
Normal
Normal
Lt. temporal lobe
cortical dysplasia
Rt. mesial occipital
dysplasia
T2 prolongation in occip
periventricular white
matter
Rt. temporal lobe
volume loss
Normal
Normal
Cortical tubers,
subependymal nodules
Ictal onset zone /
Irritative zone on EEG
Lt. frontotemporal
%L>R
%R>L
39
50
Duration
(days)
2
Lt. centrotemporal and
parietal
Lt. temporal
predominance
Lt. temporal occipital
82
16
1
39
59
2
48
48
1
Lt. frontotemporal
Lt. hemisphere
Lt. posterior quadrant
40
87
65
50
1
26
2
1
1
Lt. frontotemporal
Lt. hemisphere
39
22
32
58
3
2
Lt. temporal
Lt. posterior quadrant
Lt. temporal
8
56
29
82
34
66
1
1
4
Rt. posterior quadrant
17
56
3
Rt. frontocentral
41
42
3
Rt. parietal occipital
60
25
2
Rt. frontocentral
Rt. temporal
Rt. occipital
17
6
27
74
86
67
1
1
1
MCA = middle cerebral artery
Epilepsia (2009)
2
Figure 1. a) Example of 24 hr bilateral EDA recording (b) Comparison of frequency of
right/left EDA lateralization within patients with unilateral seizure onset. * indicates
statistical significance (p<0.05). Error bars represent 1 S.E.M.
Epilepsia (2009)
3