Atormac
briv
Neurology India
menu-bar5 Open access journal indexed with Index Medicus
  Users online: 1395  
 Home | Login 
About Editorial board Articlesmenu-bullet NSI Publicationsmenu-bullet Search Instructions Online Submission Subscribe Videos Etcetera Contact
  Navigate Here 
 Search
 
  
 Resource Links
  »  Similar in PUBMED
 »  Search Pubmed for
 »  Search in Google Scholar for
 »Related articles
  »  Article in PDF (667 KB)
  »  Citation Manager
  »  Access Statistics
  »  Reader Comments
  »  Email Alert *
  »  Add to My List *
* Registration required (free)  

 
  In this Article
 »  Abstract
 » Subjects and Methods
 » Results
 » Discussion
 » Conclusions
 »  References
 »  Article Tables

 Article Access Statistics
    Viewed434    
    Printed2    
    Emailed0    
    PDF Downloaded4    
    Comments [Add]    

Recommend this journal

 


 
Table of Contents    
ORIGINAL ARTICLE
Year : 2021  |  Volume : 69  |  Issue : 2  |  Page : 414-418

Auditory Temporal Ordering in Patients with Medial Temporal Lobe Epilepsy with and without Hippocampal Sclerosis


1 Department of Speech Pathology and Audiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
2 Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
3 Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
4 Department of Biostatistics, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India

Date of Submission28-Jun-2017
Date of Decision21-Jun-2018
Date of Acceptance27-Jun-2018
Date of Web Publication24-Apr-2021

Correspondence Address:
Dr. Aravind K Rajasekaran
Department of Speech Pathology and Audiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.314569

Rights and Permissions

 » Abstract 


Context: Temporal lobe epilepsy can affect central auditory processing (CAP) skills. Auditory temporal ordering (ATO) is a CAP skill that can be evaluated using duration pattern test (DPT).
Aim: The aim is to evaluate ATO in patients with medial temporal lobe epilepsy (MTLE) with hippocampal sclerosis (MTLE + HS) and without hippocampal sclerosis (MTLE-HS) and in their subgroups.
Settings and Design: It was a prospective cross-sectional behavioral observational study conducted in a tertiary neuropsychiatric hospital.
Subjects and Methods: The subjects were patients with refractory MTLE (N = 100), comprising 50 “MTLE + HS” patients and 50 “MTLE-HS”. Age-range matched normal healthy subjects (n = 50) formed the control group. Both groups were administered duration pattern test (DPT).
Statistical Analysis Used: Analysis of variance (ANOVA) with post hoc analysis, Dunnett's two-sided and Bonferroni, paired sample t-test, Pearson's correlation, and independent t-test.
Results: The clinical groups performed significantly poorer than the control group, and however, did not differ significantly between them. The age at onset and the duration of the seizures did not have significant relation with the test measures.
Conclusions: Patients with “MTLE + HS” as well as those with “MTLE-HS” and their respective subgroups revealed abnormal ATO indicating CAP dysfunction.


Keywords: Auditory temporal ordering, central auditory processing, duration pattern test, medial temporal lobe epilepsy
Key Message: MTLE both with HS and without HS affects ATO, a CAP skill. CAP is crucial to speech perception.


How to cite this article:
Rajasekaran AK, Shivashankar N, Sinha S, Saini J, Subbakrishna DK, Satishchandra P. Auditory Temporal Ordering in Patients with Medial Temporal Lobe Epilepsy with and without Hippocampal Sclerosis. Neurol India 2021;69:414-8

How to cite this URL:
Rajasekaran AK, Shivashankar N, Sinha S, Saini J, Subbakrishna DK, Satishchandra P. Auditory Temporal Ordering in Patients with Medial Temporal Lobe Epilepsy with and without Hippocampal Sclerosis. Neurol India [serial online] 2021 [cited 2021 May 14];69:414-8. Available from: https://www.neurologyindia.com/text.asp?2021/69/2/414/314569




Temporal processing is important for speech recognition and is the basic component of central auditory processing (CAP).[1],[2] Temporal processing encompasses four sub-processes: (a) temporal resolution, (b) temporal patterning, (c) temporal integration, and (d) temporal masking.[3] Auditory temporal ordering (ATO) is a temporal patterning task and refers to the processing of two or more sounds in their order of occurrence in time.[4] ATO can be evaluated using duration pattern test (DPT). Subjects' responses on DPT require the interaction of both hemispheres and corpus callosum.[5] DPT is found to be sensitive to central pathologies.[5],[6],[7],[8]

Temporal lobe epilepsy (TLE) with hippocampal sclerosis forms a major subgroup of patients with TLE.[9] Medial temporal lobe epilepsy (MTLE) can cause damage to the neocortex[10],[11] and corpus callosum.[12],[13] Hence, it is posited that MTLE precipitates auditory processing disorder (APD). Researchers employing auditory behavioral[14],[15],[16],[17],[18],[19],[20],[21],[22],[23] and electrophysiological measures[24],[25],[26],[27] have reported APD in patients with TLE. However, very few studies have looked into CAPD in distinct homogeneous subgroups such as MTLE with hippocampal sclerosis (MTLE + HS) and without hippocampal sclerosis (MTLE-HS). The current study was aimed to evaluate ATO using DPT in patients with “MTLE + HS” and “MTLE-HS” as well as in their subgroups, right MTLE with HS (RMTLE + HS), left MTLE with HS (LMTLE + HS), right MTLE without HS (RMTLE-HS), and left MTLE without HS (LMTLE-HS).


 » Subjects and Methods Top


Test universe: Department of Speech pathology and Audiology and Department of Neurology, National institute of mental health and neurosciences, Bangalore, Karnataka, India.

Subjects

Patients (N = 100; M:F = 66:34) who were candidates for pre-surgical evaluation for drug-resistant epilepsy participated in the study. All were under multiple antiepileptic drug regimes. Among them, 50 were “MTLE + HS” (M:F = 29:21) and 50 were “MTLE-HS” (M:F = 37:13). Age range-matched normal healthy volunteers (n = 50; M:F = 31:19) formed the control group. The sub-groups in the clinical group were RMTLE + HS (n = 23; M:F = 13:10), LMTLE + HS (n = 27; M:F = 16:11), RMTLE-HS (n = 22; M:F = 16:6), and LMTLE-HS (n = 28; M:F = 21:7).

The patients were first identified and evaluated by an epileptologist (PS and SS). Detailed clinical history, interictal electroencephalography (EEG), and video–EEG recordings constituted the neurological evaluation. Magnetic resonance imaging (MRI) was carried out on a 3-T machine (Philips Achieva) and the interpretation was done by the MRI specialist (JS) based on volume loss, signal changes, loss of normal architecture, and loss of hippocampal internal digitization, for the diagnosis of MTLE + HS. All subjects were right-handed individuals in the age range of 15 to 50 years. All had a bilateral normal hearing sensitivity (≤25 dBHL; 250 Hz to 8 KHz) on audiometry for air conduction (based on the classification of Goodman, 1965).[28] Subjects with a history/complaint of acute or chronic middle ear infections were excluded. With specific to the clinical group, patients who had premorbid neurological/psychiatric disorders, other types of epilepsy, and undergone surgical intervention for epilepsy earlier were excluded. A pre-recorded DPT[5] was routed through a calibrated clinical audiometer. The test was carried out in a sound-treated double room. The study had the approval of the institutional ethics committee of the study center. Further, the subjects gave their written informed consent for the study.

Duration pattern test

The DPT has a sequence of three consecutive 1000 Hz tones with an inter-stimulus interval of 300 ms and they were either long (L) or short (S) in duration. The long tone was of 500 ms and the short was of 250 ms duration with a rise/fall time of 10 ms. Among the three tones, one differed from the other two in the sequence. Six different response sequences (LLS, LSL, LSS, SLS, SLL, and SSL) were possible in the test. A total of 20 such stimuli (three-tone sequences) were presented monaurally at 50dB sensational level with reference to speech recognition threshold. The subjects were instructed to respond to each stimulus presentation with a verbal description of the sequence heard. The total number of correct responses (raw score) were calculated for each ear separately referred as DPT right and DPT left which were further converted into percentages (DPT right % and DPT left %). The higher percentage of correct response indicated better ATO. Practice items were provided to each subject to ensure their understanding of the task before the actual test administration.

Statistical analysis

Statistical analysis was done using SPSS 22.0 (SPSS, Chicago, IL, USA) software package. ANOVA (post hoc: Dunnett's two-sided) was done to evaluate the differences between the control and the patient groups. ANOVA (post hoc: Bonferroni) was used to compare between the patient groups. To check for the ear effect, the right and the left ear scores were compared using paired sample t-test. The relation between the phenotypes and the test measures were studied using Pearson's correlation. An independent t-test was performed to study the effect of phenotypes.


 » Results Top


There was no significant difference between the groups with respect to demographic variables [Table 1] viz., mean age and gender distribution (for all subject groups), onset, duration of seizures, and mini mental state examination (MMSE) score (for both patient groups and their subgroups).
Table 1: Demographic profile of the subjects

Click here to view


The mean percentage of correct response for the control group and the patient groups are given in [Table 2]. The control group had significantly (P < 0.001) higher scores compared to the “MTLE + HS” and “MTLE − HS” groups (DPT Right%: F (2,147) = 46.56 and DPT left%: F (2,147) = 48.29) and its subgroups (DPT Right%: F (4,145) = 23.34 and DPT left %: F (4,145) = 25.39) than other groups. However, there were no significant differences between the clinical groups.
Table 2: Mean percentage of correct response with standard deviations across groups

Click here to view


A right and left ear comparison (paired t-test) did not reveal significant differences for both control and patient groups (clinical and its subgroups). To evaluate the effect of phenotypes, subjects were sub-categorized based on cutoff values. The cutoff values (based on median values) were 10 years for age at onset and 15 years for the duration of seizure. In addition, the patients were categorized based on the seizure frequency (≥2/week or ≥2/month), last seizure attack (within 3–7 days: within 8 days to 1 month) and drug effect (two drugs or more). There was no significant difference (independent t-test) between any of the phenotypic subgroups. Further, the age at onset and duration of seizures did not reveal any correlation (Pearson's) with the ATO performance in any of the patient groups.

To differentiate the normal and abnormal scores, a cutoff value of 2 SD below the mean scores of the control group was used (Museik, 2005).[29] Accordingly, 75% cutoff value was considered for both ears. On an average, around 68% of the patients had performed below the cutoff score [Table 3].
Table 3: Percentage of subjects with scores poorer than 2SD (with reference to control group) groups

Click here to view



 » Discussion Top


The medial temporal lobe has a role in CAP.[25],[30],[31],[32] The APD has been documented in patients with TLE.[14],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25],[26],[27] The nature of APD in these patients seems to be a covert phenomenon not otherwise reported by the patients.[17] Further, researchers had reported a differential effect of various phenotypes such as age at onset, duration, frequency, and last seizure attack as well as the drug regime on AP skills.[20],[24]

In the current study, we report the performance of MTLE patients and their subgroups on DPT. The patient groups (”MTLE+HS” and “MTLE−HS”) and their subgroups (”RMTLE+HS,” “LMTLE+HS,” “RMTLE−HS,” and “LMTLE−HS”) have demonstrated poorer scores compared to the control group, indicating ATO dysfunction. The mean percentage of correct response for the patient groups ranged from 44.6% to 63.5% compared to the control group score of >90%. Poorer performance on DPT as well as on dichotic digits test (DDT) in children with TLE has been reported in an earlier study by Cranford et al (1996).[15] The mean right DPT and left ear scores were 34.4 ± 13.03% and 38.2 ± 24.83%, respectively. The authors had compared the pre-surgical and post-surgical (for epilepsy) scores in the same group of children and found that poorer performance persisted even after surgery. Similar findings have been reported in adults.[23] The authors studied the impact of epilepsy surgery on CAP function in patients (n = 22; mean age 40.41 ± 10.31 years) with “MTLE-HS”. Their findings revealed no significant difference between pre- and post-surgery on DPT, frequency pattern test (FPT), and dichotic speech test (DST). The pre-operative DPT scores were around 70% in the “MTLE−HS'' group and the subgroups (RMTLE − HS and left MTLE-HS) compared to the cutoff (81%), indicating ATO dysfunction.

CAP dysfunctions in patients with TLE generally have been studied as a whole group. Meneguello et al. (2006)[18] in their study (n = 8; age = 22 to 51 years) reported poorer performance on DPT, DDT, and nonverbal dichotic test except sound location test in patients with TLE. The average DPT right and left score for the patient groups was 53.3 and 56.6%, respectively, and that of the control group was 85.2 and 85.7%, respectively. In a detailed study on distinct TLE subgroups, Han et al. (2011)[20] recruited patients (n = 28) with hippocampal sclerosis (right = 10, left = 8, and bilateral = 2) and without hippocampal sclerosis (n = 8). The same patients were subcategorized with reference to seizure foci (right = 15, left = 10, and bilateral = 3). The authors reported poorer scores (mean: 73.1 ± 22.1%) on FPT, DPT, and DDT in patients compared to the normal cutoff score (81%), indicating ATO dysfunction. The findings of our study corroborate with the findings of the above studies.

In the current study, the differences between the control and the patient groups were statistically significant. However, no significant effect was observed among those with and without HS. This implicates that there is no distinct effect of lesion or seizure on ATO skill. This is similar to the findings on DPT reported by Han et al. (2011).[20] The authors had further reported that on FPT measure, the patients with HS performed significantly poor than without HS. A similar poor performance by the “TLE with HS” group has been reported on rapid auditory processing task.[33] However, in the current study, FPT, as well as rapid auditory processing task, was not included as a part of the test protocol.

The non-lesion side of the clinical groups too showed poor scores in the current study. Further, a comparison between the right and the left ear (lesion vs. non lesion side) did not yield any significant differences. A similar finding has been reported by Meneguello et al. (2006).[18] The observed bilateral deficit could be attributed cumulatively to the nature of the test (DPT) employed and the underlying pathology. First, unilateral cerebral lesion causes bilateral reduction of DPT scores, as both hemispheres contribute during DPT testing.[3],[7] Second, bilateral deficits have been reported in unilateral TLE patients using other CAP test measures.[14],[21],[22] Further, bihemispheric abnormality[11],[34],[35],[36] and damage to corpus callosum[12],[13] have been documented in patients with unilateral TLE.

This study also documents no significant difference between the seizure phenotypic categories (early vs. late onset, less vs. long duration, less vs. more frequency, recent vs. early attack, and less number vs. more number of drugs) on the DPT measures. Similar results are reported in the literature.[20] Further, in the current study, the age at onset and duration of seizures did not show any significant correlation with that of the DPT measures. Contrarily, Han et al. (2011)[20] reported a negative correlation of DPT and dichotic measures with respect to the duration of seizures. However, they did not find a correlation on FPT measure and also with respect to age at seizure onset. Similar to the current study, Chi Chen et al. (2001)[37] in their study reported no correlation with respect to age at onset and duration of seizure in relation to auditory P300 measure.

To find the number of subjects having an abnormal score, a cutoff value of 75% was considered in the current study. Based on this criterion, it was found approximately 68% of patients had an abnormal score. Han et al. (2011)[20] reported that 57.1% patients with TLE as having abnormal scores. The difference between our study and of theirs could be due to slightly higher cutoff score (81%) considered by the authors compared to our study. Also, in the present study, the cutoff score was derived out of age range-matched control group and the sample size was on the higher side. Further, probing of the results reveal higher failure percentage in patients with left hemisphere damage (LMTLE + HS and LMTLE-HS) compared to those with right hemisphere damage (RMTLE + HS and RMTLE-HS). This could be due to the fact that the left hemisphere is generally the language dominant making the verbal responses difficult during the DPT.


 » Conclusions Top


The current study implicates ATO deficits in patients with MTLE with and without hippocampal sclerosis and in their distinct subgroups. In agreement with previous studies, the current study further strengthens and justifies the role of audiological tests in unravelling APD in patients with TLE. These deficits seem to be a covert phenomenon, and hence require a thorough understanding of its pathophysiological basis and its overall effect on quality of life of the individuals with TLE. Future studies encompassing various central auditory measures should focus towards profiling auditory skills deficits and expand it to remediation strategies. This is more pertinent particularly in the school-going population as APD secondary to TLE may have a direct impact on their learning outcomes.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
 » References Top

1.
Fu QJ. Temporal processing and speech recognition in cochlear implant users. Neuroreport 2002;13:1635-9.  Back to cited text no. 1
    
2.
Helfer KS, Vargo M. Speech recognition and temporal processing in middle-aged women. J Am Acad Audiol 2009;20:264-71.  Back to cited text no. 2
    
3.
Shinn J. Temporal processing tests. In: Musiek F, Chermak G, editors. Handbook of central auditory processing disorders: Auditory neuroscience and diagnosis. San Diego: Plural Publishing; 2014.  Back to cited text no. 3
    
4.
Pinheiro M, Museik FE. Asessment of central auditory dysfunctions: Foundations and clinical correlates. Baltimore: Williams and Wilkins; 1985.  Back to cited text no. 4
    
5.
Museik FE, Baran JA, Pinheiro ML. Duration pattern recognition in normal subjects and patients with cerebral and cochlear lesions. Int J Audiol 1990;29:304-13.  Back to cited text no. 5
    
6.
Strouse AL, Hall JW, Burger MC. Central auditory processing in Alzheimer's disease. Ear Hear 1995;16:230-8.  Back to cited text no. 6
    
7.
Bamiou DE, Musiek FE, Stow I, Stevens J, Cipolotti L, Brown MM, et al. Auditory temporal processing deficits in patients with insular stroke. Neurology 2006;67:614-9.  Back to cited text no. 7
    
8.
Bamiou DE, Free SL, Sisodiya SM, Chong WK, Musiek F, Williamson KA, et al. Auditory interhemispheric transfer deficits, hearing difficulties, and brain magnetic resonance imaging abnormalities in children with congenital aniridia due to PAX6 mutations. Arch Pediatr Adolesc Med 2007;161:463-9.  Back to cited text no. 8
    
9.
Engel J. Etiology as a risk factor for medically refractory epilepsy: A case for early surgical intervention. Neurology 1998;51:1243-4.  Back to cited text no. 9
    
10.
Zumsteg D, Friedman A, Wieser H, Wennberg R. Propagation of interictal discharges in temporal lobe epilepsy: Correlation of spatiotemporal mapping with intracranial foramen ovale electrode recordings. Clin Neurophysiol 2006;117:2615-26.  Back to cited text no. 10
    
11.
McDonald CR, Hagler DJ, Ahmadi ME, Tecoma E, Iragui V, Gharapetian L, et al. Regional neocortical thinning in mesial temporal lobe epilepsy. Epilepsia 2008;49:794-803.  Back to cited text no. 11
    
12.
Weber B, Luders E, Faber J, Richter S, Quesada CM, Urbach H, et al. Distinct regional atrophy in the corpus callosum of patients with temporal lobe epilepsy. Brain 2007;130:3149-54.  Back to cited text no. 12
    
13.
Kim H, Piao Z, Liu P, Bingaman W, Diehl B. Secondary white matter degeneration of the corpus callosum in patients with intractable temporal lobe epilepsy: A diffusion tensor imaging study. Epilepsy Res 2008;81:136-42.  Back to cited text no. 13
    
14.
Collard ME, Lesser RP, Lüders H, Dinner DS, Morris HH, Hahn JF, et al. Four dichotic speech tests before and after temporal lobectomy. Ear Hear 1986;7:363-9.  Back to cited text no. 14
    
15.
Cranford JL, Kennalley T, Svoboda W, Hipp K. Changes in central auditory processing following temporal lobectomies in children. J Am Acad Audiol 1996;7:289-95.  Back to cited text no. 15
    
16.
Ortiz KZ, Pereira LD., Borges, Alda CLDC, Vilanova LCP. Staggered spondaic word test in epileptic patients. Sao Paulo Med J 2002;120:185-8.  Back to cited text no. 16
    
17.
Boatman DF, Lesser RP, Crone NE, Krauss G, Lenz FA, Miglioretti DL. Speech recognition impairments in patients with intractable right temporal lobe epilepsy. Epilepsia 2006;47:1397-401.  Back to cited text no. 17
    
18.
Meneguello J, Leonhardt FD, Pereira LD. Auditory processing in patients with temporal lobe epilepsy Summary. Rev Bras Otorrinolaringol 2006;7272:496-504.  Back to cited text no. 18
    
19.
Carlsson G, Wiegand G, Stephani U. Interictal and postictal performances on dichotic listening test in children with focal epilepsy. Brain Cogn 2001;76:310-5.  Back to cited text no. 19
    
20.
Han MW, Ahn JH, Kang JK, Lee EM, Lee JH., Bae JH, et al. Central auditory processing impairment in patients with temporal lobe epilepsy. Epilepsy Behav 2011;20:370-4.  Back to cited text no. 20
    
21.
Aravindkumar R, Shivashankar N, Satishchandra P, Sinha S, Saini J, Subbakrishna D K. Temporal resolution deficits in patients with refractory complex partial seizures and mesial temporal sclerosis (MTS). Epilepsy Behav 2012;24:126-30.  Back to cited text no. 21
    
22.
Rajasekaran A, Shivashankar N, Satishchandra P, Sinha S, Saini J, Subbakrishna DK. Dichotic perception in patients with and without medial temporal sclerosis. Speech Lang Hear 2014;17:153-9.  Back to cited text no. 22
    
23.
Han SH, Lee EM, Choi EJ, Ryu HU, Kang JK, Chung JW. Changes in central auditory processing in patients with mesial temporal lobe epilepsy after anterior temporal lobectomy with amygdalohippocampectomy. J Clin Neurol 2016;12:151-9.  Back to cited text no. 23
    
24.
Triantafyllou NI, Zalonis I, Kokotis P, Anthracopoulos M, Siafacas A, Malliara S, et al. Cognition in epilepsy: A multichannel event related potential (P300) study. Acta Neurol Scand 1992;86:462-5.  Back to cited text no. 24
    
25.
Honda M, Suwazono S, Nagamine T, Yonekura Y, Shibasaki H. P300 abnormalities in patients with selective impairment of recent memory. J Neurol Sci 1996;139:95-105.  Back to cited text no. 25
    
26.
Brodtkorb E, Steinlein OK, Sand T. Asymmetry of Long-latency Auditory Evoked Potentials in LGI1-related Autosomal Dominant Lateral Temporal Lobe Epilepsy. Epilepsia 2005;46:1692-4.  Back to cited text no. 26
    
27.
Lin YY, Hsiao FJ, Shih YH, Yiu CH, Yen DJ, Kwan SY, et al. Plastic phase-locking and magnetic mismatch response to auditory deviants in temporal lobe epilepsy. Cereb Cortex 2007;17:2516-25.  Back to cited text no. 27
    
28.
Goodman AC. Reference zero levels for pure-tone audiometers. Am Speech Lang Hear Assoc 1965;7:262-73.  Back to cited text no. 28
    
29.
Musiek FE, Shinn, JB, Jirsa R, Bamiou DE, Baran JA, Zaida E. GIN (Gaps-In-Noise) test performance in subjects with confirmed central auditory nervous system involvement. Ear Hear 2005;26:608-18.  Back to cited text no. 29
    
30.
Knight RT. Contribution of human hippocampal region to novelty detection. Nature 1996;383:256-9.  Back to cited text no. 30
    
31.
Nishitani N, Ikeda A, Nagamine T, Honda M, Mikuni N, Taki W, Shibasaki H. The role of the hippocampus in auditory processing studied by event-related electric potentials and magnetic fields in epilepsy patients before and after temporal lobectomy. Brain 1999;122:687-707.  Back to cited text no. 31
    
32.
Takakura H, Umeno K, Tabuchi E, Hori E, Miyamoto K, Aso S, et al. Differential activation in the medial temporal lobe during a sound-sequence discrimination task across age in human subjects. Neuroscience 2003;119:517-32.  Back to cited text no. 32
    
33.
Bidet-Caulet A, Ye XL, Bouchet P, Guénot M, Fischer C, Bertrand O. Non-verbal auditory cognition in patients with temporal epilepsy before and after anterior temporal lobectomy. Front Hum Neurosci 2009;3:42.  Back to cited text no. 33
    
34.
Ehrlà N. Processing of rapid auditory information in epileptic patients with left temporal lobe damage. Neuropsychologia 2001;39:525-31.  Back to cited text no. 34
    
35.
Adam C, Hasboun D, Clemenceau S, Dupont S, Baulac M, Hazemann P. Fast contralateral propagation of after-discharges induced by stimulation of medial temporal lobe. J Clin Neurophysiol 2004;21:399-403.  Back to cited text no. 35
    
36.
Araujo D, Santos AC, Velasco TR, Wichert-Ana L, Terra-Bustamante VC, Alexandre V, et al. Volumetric Evidence of Bilateral Damage in Unilateral Mesial Temporal Lobe Epilepsy. Epilepsia 2006;47:1354-9.  Back to cited text no. 36
    
37.
Chen RC, Tsai SY, Chang YC, Liou HH. Seizure frequency affects event-related potentials (P300) in epilepsy. J Clin Neurosci 2001;8:442-6.  Back to cited text no. 37
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

Top
Print this article  Email this article
   
Online since 20th March '04
Published by Wolters Kluwer - Medknow