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Table of Contents    
CASE REPORT
Year : 2020  |  Volume : 68  |  Issue : 1  |  Page : 170-172

Left Temporal Lobectomy Using Functional MRI in a Math Genius: A Case Report


1 Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
2 Department of Biomedical Engineering/NMR, IIT/AIIMS, New Delhi, India
3 Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
4 Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
5 Department of Neuropsychology, All India Institute of Medical Sciences, New Delhi, India

Date of Web Publication28-Feb-2020

Correspondence Address:
Prof. Madhavi Tripathi
Department of Neurology, Room No. 7005, CN Centre, All India Institute of Medical Sciences, New Delhi
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0028-3886.279704

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 » Abstract 


Standard treatment of drug-refractory epilepsy, due to left mesial temporal sclerosis, is anterior temporal lobectomy with amygdalohippocampectomy (ATL). This carries a risk of cognitive deficits, including comprehension, verbal memory, and visual memory. Preoperative language lateralization and localization is important to preserve these functions. Often Wada testing is used for these, but it carries risk due to its invasive nature. In addition, it can lateralize but not localize and may not be readily available. We hereby present a mathematics genius who underwent left ATL under the guidance of functional MRI and neuropsychological assessment alone, resulting in the preservation of all of his cognitive abilities even in the immediate postoperative period. A video demonstration of his calendar likeability is also shown.


Keywords: Cognition, functional MRI, mesial temporal sclerosis, Wada testing
Key Messages: Left-sided Anterior temporal lobectomy (ATL) makes a patient at risk for language and verbal memory deficits. The functional magnetic resonance imaging helps to predict the localization of these functions and can make safe ATL possible.


How to cite this article:
Bajaj J, Chaudhary K, Chandra P S, Ramanujam B, Girishan S, Doddamani R, Tripathi M, Nehra A, Tripathi M. Left Temporal Lobectomy Using Functional MRI in a Math Genius: A Case Report. Neurol India 2020;68:170-2

How to cite this URL:
Bajaj J, Chaudhary K, Chandra P S, Ramanujam B, Girishan S, Doddamani R, Tripathi M, Nehra A, Tripathi M. Left Temporal Lobectomy Using Functional MRI in a Math Genius: A Case Report. Neurol India [serial online] 2020 [cited 2020 Mar 29];68:170-2. Available from: http://www.neurologyindia.com/text.asp?2020/68/1/170/279704




Left temporal lobe epilepsy (TLE) may be associated with verbal memory, calculations, and language deficits.[1] Anterior temporal lobectomy with amygdalohippocampectomy (ATL) is a highly effective treatment for alleviating epilepsy in these patients;[2],[3] however, it can be associated with verbal and cognitive deficits in 30–50% of the patients.[1] Selective amygdalohippocampectomy (SAH), and even minimally invasive treatments such as radiofrequency thermoablation, laser ablation of the hippocampus cannot prevent these deficits since they essentially resect or destroy hippocampus. Many patients undergo responsive neurostimulation (RNS) or deep brain stimulation (DBS) of the anterior nucleus of the thalamus, but these are palliative treatments and are associated with lower rates of seizure freedom compared to ATL.[4] The Wada test is considered a gold standard to delineate the memory and language areas, but this test is invasive, carries risk, is costly, and is not available everywhere. In such a situation, functional magnetic resonance imaging (fMRI) has been recommended for localization and lateralization of patient's memory and language.[5] Nevertheless, the reliability of the fMRI to clear a mathematics genius with left TLE for ATL is not known. Indeed, a robust examples of successful fMRI use in delineating cognitive abilities are yet undescribed.

We here present a patient with left TLE who had amazing calculation skills for spoken language. He could identify the day of the week of any time in history simply by knowing its date. This patient underwent successful ATL with the preservation of all his cognitive abilities, even in the immediate postoperative period only on the guidance of fMRI and neuropsychological assessment.


 » Case Report Top


Our patient was a right-handed 23-year-old man, a student, with amazing ability to identify the day of the week of any given date in history in 1–2 s. He had drug-refractory epilepsy since eight years of age and difficulty remembering new things since the previous year. The seizures occurred 3–4 times/month, with an aura of uneasiness, fearfulness, and automatisms with the left hand, followed by tonic contractions of the right upper and lower limb and generalization. He was on levetiracetam, oxcarbazepine, and clobazam in adequate doses without relief from seizures. The MRI was suggestive of left hippocampal sclerosis, video electroencephalogram (VEEG) showed T3 spikes, and subtraction ictal single-photon emission computed tomography showed left temporal localization [Figure 1]. The neuropsychological assessment showed impaired verbal memory of immediate, delayed and learning ability, and immediate and delayed visual memory. He had intact visuoconstructive ability and normal focused and sustained attention, and intact long-term percent recall (93%).
Figure 1: (a) Shows the preoperative fluid-attenuated inversion recovery MRI of the patient showing left hippocampal atrophy with dilated temporal horn. (b) Shows the subtraction ictal SPECT revealing the hotspot from left mesial temporal lobe. (c) Shows the fMRI for word generation tasks with BOLD signal from bilateral inferior and middle frontal gyrus. (d) Shows the fMRI for comprehension task with BOLD signal from bilateral temporal lobe (right > left). (e) Shows the fMRI for semantic memory with BOLD signal from right temporal lobe and superior temporal gyrus of left temporal lobe. (f) Shows the postoperative computed tomography of the patient with ATL done

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fMRI task details

The fMRI study was carried out using a 32-channel head coil on a 3.0T MR Scanner (Ingenia 3.0T TX, M/s. Philips). The language and semantic verbal memory tasks were incorporated into a block design with four cycles of activity alternating with the baseline.

During the word generation (WGT) and syntax reading tasks (SRT), the case was instructed to read simple semantic Hindi words and sentences. For the semantic memory task (SMT), the instruction was to remember the correct synonym or antonym of the noun among the four options represented by an LED screen. During the semantic-syntactic and comprehension task (SSCT), the subject was asked to correct the syntax of the jumbled sentences. The entire paradigm was generated using SuperLab software (Cedrus, Inc., San Pedro, CA, USA), and the visual cues were presented using an MR- compatible LED screen.

FMRI data analysis

The fMRI data were analyzed by the statistical parametric mapping (SPM) software (Wellcome Trust, London, UK; version SPM 12) using MATLAB (version: 7.12.0.635 (R2011), Math- Works, Inc., Natick, MA, USA). The BOLD whole-brain series were corrected for motion. Data were transformed using linear warps into a standard anatomical space during normalization processing. Finally, data were spatially smoothed (6 Hz) before post-processing. Brain activation patterns were overlaid onto the normalized 3D T1-weighted and render images. The coordinates of the local maxima of the threshold (P value uncorrected: 0.001) SPM map was converted from MNI frame to standard Talairach coordinates using Ginger ALE, and subsequently, an automated procedure (Talairach Client) was performed to assign an anatomic label to these coordinates by searching for the label associated with the nearest gray matter coordinate.[6]

His fMRI for word production tasks showed blood oxygen level-dependent (BOLD) signal from the bilateral inferior frontal gyrus, for comprehension showed the bilateral temporal lobe (right > left) and for semantic memory showed the right temporal lobe and left superior temporal lobe activation [Figure 1].

The patient underwent ATL considering anatomo-electro-clinical concordance and shifting of verbal and cognitive functions to the right side. He had an uneventful postoperative course. The patient had complete preservation of his cognitive ability even in the immediate post operative period, as shown in Video 1. The histopathology report was suggestive of mesial temporal sclerosis. At 15 months follow-up, he had no seizures with improvement of his learning abilities.


 » Discussion Top


Our patient had concordance between clinical semiology, VEEG, and imaging, guiding to the left TLE localization. He had unique arithmetic skills even with impairment of verbal memory shown on neuropsychological assessment. This was due to preserved language areas in bilateral superior temporal gyrus and inferior frontal gyrus and calculation in the parietal lobe. Left ATL carried inherent risks for his amazing abilities. Since the Wada test is invasive, does not allow for localization of cognitive functions, and is not available in out country, we did fMRI along with neuropsychological assessment to localize the functions. The fMRI showed comprehension and verbal memory representation in bilateral temporal lobes with right > left. Even the motor speech area was also more in the right inferior frontal gyrus. This gave us the confidence to proceed with left ATL surgery.

There is increasing evidence of fMRI comparability to the gold standard Wada test for language studies,[7] and as a predictor of postoperative verbal memory decline after left temporal lobectomy.[8] fMRI can be combined with intraoperative neuronavigation and cortical stimulation to determine language mapping;[9] however, we could not do it because our patient did not give the consent for awake surgery.

Mathematic skills involve the comprehension of written or spoken language, number processing, and calculation, retrieving arithmetic facts, and producing the result in writing or speaking. Calculation skills per se involve bilateral (left > right) horizontal intraparietal sulcus, prefrontal, and cingulate cortex. These skills for reading input has shown to be preserved in temporal lobe atrophy,[10] but one can have his calculation skills in jeopardy for spoken input in left TLE.

Being able to identify the day of the week based on a date (date, month, and year) involves multiple calculations and remembering some numbers. Its formula is (year code + month code + century code + date number – leap year code) mod 7. One has to remember the codes mentioned above and quickly do calculations to answer it. Our patient did these calculations within 1–2 seconds. This he could do even with a left TLE.

This case is good evidence of an effective use of noninvasive investigations to perform a safe ATL in left TLE in a right-handed executive person. Complex calculation skills, semantic verbal memory, comprehension, and motor speech were preserved in this case using fMRI and neuropsychological assessment.


 » Conclusion Top


Functional MRI is an effective method to guide ATL in left TLE.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
 » References Top

1.
Helmstaedter C, Kurthen M, Lux S, Reuber M, Elger CE. Chronic epilepsy and cognition: A longitudinal study in temporal lobe epilepsy. Ann Neurol 2003;54:425-32.  Back to cited text no. 1
    
2.
Wiebe S, Blume WT, Girvin JP, Eliasziw M. A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med 2001;345:311-8.  Back to cited text no. 2
    
3.
Dwivedi R, Ramanujam B, Chandra PS, Sapra S, Gulati S, Kalaivani M, et al. Surgery for drug-resistant epilepsy in children. N Engl J Med 2017;377:1639-47.  Back to cited text no. 3
    
4.
Fisher R, Salanova V, Witt T, Worth R, Henry T, Gross R, et al. Electrical stimulation of the anterior nucleus of thalamus for treatment of refractory epilepsy. Epilepsia 2010;51:899-908.  Back to cited text no. 4
    
5.
Chaudhary K, Kumaran SS, Chandra SP, Wadhawan AN, Tripathi M. Mapping of cognitive functions in chronic intractable epilepsy: Role of fMRI. Indian J Radiol Imaging 2014;24:51-6.  Back to cited text no. 5
[PUBMED]  [Full text]  
6.
Eickhoff SB, Bzdok D, Laird AR, Kurth F, Fox PT. Activation likelihood estimation meta-analysis revisited. Neuroimage 2012;59:2349-61.  Back to cited text no. 6
    
7.
Woermann FG, Jokeit H, Luerding R, Freitag H, Schulz R, Guertler S, et al. Language lateralization by Wada test and fMRI in 100 patients with epilepsy. Neurology 2003;61:699.  Back to cited text no. 7
    
8.
Richardson MP, Strange BA, Thompson PJ, Baxendale SA, Duncan JS, Dolan RJ. Pre-operative verbal memory fMRI predicts post-operative memory decline after left temporal lobe resection. Brain 2004;127:2419-26.  Back to cited text no. 8
    
9.
Kumar A, Chandra PS, Sharma BS, Garg A, Rath GK, Bithal PK, et al. The role of neuronavigation-guided functional MRI and diffusion tensor tractography along with cortical stimulation in patients with eloquent cortex lesions. Br J Neurosurg 2014;28:226-33.  Back to cited text no. 9
    
10.
Rossor MN, Warrington EK, Cipolotti L. The isolation of calculation skills. J Neurol 1995;242:78-81.  Back to cited text no. 10
    


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