Prof. Thomas Gregor Issac

Associate Professor

Dr. Thomas Gregor Issac completed his M.B.B.S training from M.O.S.C Medical College (Mahatma Gandhi University), Kerala from 2003-2009 and subsequently got selected for Ph.D. in Clinical Neurosciences Programme under the ICMR MD-PhD Talent Search programme which he pursued from August 2011 till July 2016. His PhD dissertation focused on the role of “Renin-Angiotensin-Aldosterone System in Cognitive deterioration in patients with cerebral small vessel disease” wherein he examined the genetic, cognitive, and neuroimaging profiles of a cohort of more than 200 patients across the spectrum of vascular cognitive impairment. Subsequently, he was selected for the MD Psychiatry course at the prestigious National Institute of Mental Health and Neurosciences (NIMHANS) and trained as a Junior Resident in the Department of Psychiatry from July 2016 to June 2019. His MD dissertation involved studying the “Role of APO E4 allele in vascular cognitive impairment”. He has also cleared DNB in Psychiatry. After his post-graduation in psychiatry, he started pursuing DM (Geriatric psychiatry) at NIMHANS, wherein he is currently in his final year of Senior Residency. His DM dissertation is titled “Naturalistic follow up study on older adults with unipolar major depression after in-patient care in a tertiary centre”.

A multimodal interventional approach to address cognitive disorders in the elderly

I have always been fascinated by clinical research and my research focuses on understanding the neurobiological underpinnings of cognitive disorders. Being from a medical background, my initial work was on the clinical understanding of the various dementias and included understanding “how, when and why” a patient with dementia shows specific clinical phenomena which often gives clues to the diagnosis and subtyping the various forms of dementia. Understanding the role of reversible causes of dementia and its mitigation is therefore of paramount importance. As the ageing population is increasing, understanding the trajectories, modifiers and modulators of healthy ageing and transition from mild cognitive impairment to major neurocognitive impairment gains significance. Targeted interventions tailored to address the vulnerable elderly from middle age or even before would be the most important translational aspect of my research. Our team also tries to understand the role of hitherto considered benign white matter changes and its role in tilting the balance of mild cognitive impairment towards dementia. My PhD work was hence specifically focused on the role of specific molecular mechanisms driving cognitive deterioration in patients with Cerebral Small Vessel Disease. This work was seminal with respect to the fact that it looked in a holistic manner not just the clinical data but comprehensively assessed the neuropsychological, imaging and genetic correlates associated with respect to the same in a cohort of more than 200 patients. This work was further extrapolated during my MD studies wherein I looked into the role of APO E4 allele in modulating the course and prognosis in the cohort of patients with vascular cognitive impairment as further ahead during my DM wherein I tried to identify the various trajectories that late-life depression would take and its likely link and evolution into neurocognitive disorders like dementia. These are just humble beginnings and there is a need for more such cohort studies in understanding the role of modifiable risk factors including epigenetics that could increase the incidence of dementia in our elderly. My research also gives importance to the public health approach for dementias and in the role of developing policy considerations, ethical and sociological aspects of ageing and explores due concerns of the stakeholders especially patients with cognitive impairment and their caregivers, rehabilitation options and inputs for advocacy as well. It is opportune that this decade is considered as that of “Healthy Ageing” by the World Health Organization (WHO) and a comprehensive understanding of geriatric physical and mental health would pave way for developing better access to pathways of care and provision of early intervention strategies and “bench to bedside” translation of research.

Sandhya G ( Ph.D Student)

I have completed my integrated M.Sc. in Life Sciences from Central University of Tamil Nadu. My Ph.D. work is primarily focussed on studying the association of nutrition with cognitive performance. Apart from research, I also enjoy dancing and listening to music.
E-mail ID :


Ms. Dwaiti Roy ( Ph.D Student)

I completed my B.Sc. in Psychology from Calcutta University and M.Sc. in Psychology from Banaras Hindu University. My main area of interest is neuromodulatory effects on aging brain. Besides studying I love animal keeping and nurturing, and also watching series.
E-mail ID:


Ms. Anjana Menon( Research Assistant)

I pursued my bachelor’s degree in zoology from St Teresa’s College. After that I went on to pursue master’s in Zoology from St Berchman’s College. I am an aspiring neuroscientist. Currently I am focusing on the brain-environment interaction and positive impact of multilingualism on cognitive performance. In addition to my interests in neuroscience, I enjoy painting, singing and listening to music during my spare time.
 Email id:



  1. Singh S, Malo PK, Mensegere AL, Thomas Gregor Issac. Letter to Editor: Atrophy asymmetry in hippocampal subfields in patients with Alzheimer’s disease and mild cognitive impairment. Experimental Brain Research. 2023 Jul 28:1-1.

  2. Menon AJ, Sandhya G, Varadharajan A, Rai P, Sundarakumar JS, Thomas Gregor Issac. Particulate Matter 2.5–Muddling the Healthy Brain. Journal of Psychiatry Spectrum. 2023 Jul 1;2(2):129-30.

  3. Sandhya G, Thomas Gregor Issac. “Thalaikoothal”–A Less-Known Practice of Senicide in Rural India. Journal of Psychiatry Spectrum. 2023 Jul 1;2(2):127-8.

  4. Roy D, Varadharajan A, Joe N, Jain S, Sunny AS, Thomas Gregor Issac. “Relax, Refresh, and Refocus:” A Brief Account on the Potential Utility of Snoezelen in Dementia. Journal of Psychiatry Spectrum. 2023 Jul 1;2(2):109-12.

  5. Maestre, G., Carrillo, M., Kalaria, R., Acosta, D., Adams, L., Adoukonou, T., … & African Dementia Consortium. (2023). The Nairobi Declaration—Reducing the burden of dementia in low?and middle?income countries (LMICs): Declaration of the 2022 Symposium on Dementia and Brain Aging in LMICs. Alzheimer’s & Dementia 19: 1105-1108.
  6. Kumar CT, Varghese M, Duddu V, Vaitheswaran S, Srivastava S, Shaji KS, …, Thomas Gregor Isaac, Chandra M. Indian Psychiatric Society multicentre study: Diagnostic patterns, comorbidity and prescription practices for patients with Dementia. Indian Journal of Psychiatry 2023;65:52-60.
  7. Vasanthra CR, Ammapattian T, Antony S, Rao GN, Prasad KM, Anu KN, Thomas Gregor Issac and Sivakumar Palanimuthu Thangaraju. Home-based care of persons with dementia during COVID-19 pandemic: Caregivers’ experiences. Journal of Geriatric Mental Health 2022;9:9-12.
  8. Suhas S, Malo PK, Kumar V, Thomas Gregor Issac, Chithra NK, Bhaskarapillai B, Reddy YCJ, Rao NP. Treatment strategies for serotonin reuptake inhibitor-resistant obsessive-compulsive disorder: A network meta-analysis of randomised controlled trials. The World Journal of Biological Psychiatry. 2022 Jun 14:1-16. doi: 10.1080/15622975.2022.2082525.
  9. Sharad Philip, Thomas Gregor Issac, Arjita Sharda, Avinash Shekhar, Suicide prevention strategy in India, The Lancet Psychiatry, Volume 9, Issue 3, 2022,Page 192,ISSN 2215-0366,
  10. Thomas Gregor Issac, Mukku SSR, Mangalore S, Sinha P, Sivakumar PT. Reflected image processing abnormalities in dementia – a case series and review. Neurocase. 2022 May 8:1-5. doi: 10.1080/13554794.2022.2072227. PMID: 35531907.
  11. Issac, A.C., Thomas Gregor Issac, Baral, R., Bednall, T.C. and Thomas, T.S., 2021. Why you hide what you know: Neuroscience behind knowledge hiding. Knowledge and Process Management, 28(3), pp.266-276.
  12. Philip S, Shoib S, Thomas Gregor Issac, Javed S. Diagnostic challenges posed by intersections between post-acute covid syndrome and neurocognitive disorders. Asian Journal of Psychiatry. 2022 Jan;67:102936. DOI: 10.1016/j.ajp.2021.102936. PMID: 34844177; PMCID: PMC8606183.
  13. Ramesh A, Thomas Gregor Issac, Mukku SS, Sivakumar PT. Companionship and Sexual Issues in the Aging Population. Indian Journal of Psychological Medicine. 2021 Oct 5:02537176211045622.
  14. Thomas Gregor Issac, Ramesh A, Reddy SS, Sivakumar PT, Kumar CN, Math SB. Maintenance and Welfare of Parents and Senior Citizens Act 2007: A Critical Appraisal. Indian Journal of Psychological Medicine. 2021 Oct 3:02537176211043932.
  15. Krishna, G., Sivakumar, P.T., Dahale, A.B., Thomas Gregor Issac, Mukku, S.S.R., Unni, A.K., Sinha, P., Varghese, M. and Subramanian, S., 2020. Increased prolidase activity in Alzheimer’s dementia: A case-control study. Asian journal of psychiatry, 53, p.102242.
  16. Thomas Gregor Issac Be in Control before You Lose Control. Journal of Neurosciences in Rural Practice, 11(3), p.365.
  17. Mukku SS, Jagtap N, Thomas Gregor Issac, Mangalore S, Sivakumar PT. Psychotic symptoms in Frontotemporal dementia with right fronto-temporal atrophy. Asian Journal of Psychiatry. 2020 Apr 18:102040.
  18. Krishna G, Kn A, Kumar RS, Sagar BC, Philip M, Dahale AB, Thomas Gregor Issac, Mukku SS, T Sivakumar P, Subramanian S. Higher levels of lysosomal associated membrane protein-2 (LAMP-2) in plasma exosomes from Alzheimer’s disease: An exploratory study from South India. Asian journal of psychiatry. 2019 Dec 9;48:101898.
  19. Chandra SR, Chakravarthula NR, Thomas Gregor Issac, Philip M. Long-term follow-up of patients with multiple sclerosis treated with a cost-effective protocol from a rural medical center in India: a retrospective case series. Asia Pacific Journal of Clinical Trials: Nervous System Diseases. 2019 Oct 1;4(4):90.
  20. Issac AC, Thomas Gregor Issac. Unravelling the Nexus between neuroscience and leadership research. Management Decision. 2019 Nov 12.
  21. Chandra SR, Shivaram S, Thomas Gregor Issac Reflected images processing and the diseases of the brain. International Journal of Health & Allied Sciences. 2019 Jul 1;8(3):174.
  22. Chandra SR, Koti N, Harikrishna GV, Mailankody P, Ramanujam CN, Pavagada SM, Thomas Gregor Issac. A rare treatable cause for atypical frontotemporal dementia with multiple fractures in a young female. Journal of Geriatric Mental Health. 2018 Jul 1;5(2):170.
  24. Chandra SR, Suresh A, Annapoorni CSV, Rita Christopher, Asheeb A, Thomas Gregor Issa Skin, hair and nails as pointers to neurocognitive disorders in children: our experience. J Clin Psychiatry Cog Psychol. 2018;2(2):5-10.
  25. Chandra SR, Huddar A, Varghese N, Koti N, Ganaraja VH, Pooja M and Thomas Gregor Issac. Myasthenia Gravis-Our Experience in the Last Three Years with Interesting Associations. J Gen Pract (Los Angel). 2018;6(363):2.
  26. Thomas Gregor Issac, Telang AV, Chandra SR. Trichotillomania ranging from “ritual to illness” and as a rare clinical manifestation of frontotemporal dementia: Review of literature and case report. International journal of trichology. 2018 Mar;10(2):84.
  27. Gowda GS, Telang A, Sharath R, Thomas Gregor Issac, Haripriya C, Ramu PS, Math SB. Use of newer technologies with existing service for family reintegration of unknown psychiatric patients: A case series. Asian Journal of Psychiatry. 2017 Oct 29.(ahead of print)-published online
  28. Chandra SR, Thomas Gregor Issac, Gupta N. Snakebite, Antivenom and Mitochondrial Toxicity. Annals of Medical and Health Sciences Research. 2017;7(3).
  29. Thomas Gregor Issac, Chandra SR, Gupta N, Rukmani MR, Deepika S, Sathyaprabha TN. Autonomic dysfunction: A comparative study of patients with Alzheimer’s and frontotemporal dementia – A pilot study.Journal of Neurosciences in Rural Practice. 2017;8(1):84-88.
  30. Chandra, SR, Thomas Gregor Issac, Mane, M., Bharath, S., & Nagaraju, B. C. (2017). Long Loop Reflex 2 in Patients with Cortical Dementias: A Pilot Study.Indian Journal of Psychological Medicine 2017; 39(2), 164–168.
  31. Chandra SR, Asheeb A, Dash, Retna N, Ravi Teja KV, Thomas Gregor Issac, Role of electroencephalography in the diagnosis and treatment of neuropsychiatric border zone syndromes. Indian J Psychological Medicine 2017;39: pages 243-249.
  32. Chandra SR, Anand B, Thomas Gregor Issac, Median and common peroneal neuropathy in coir workers of Alappuzha district , Kerala, Annals of Indian Academy of Neurology 2017:20:23-8.
  33. Thomas Gregor Issac, Chandra SR, “ A lady of few words” Review of literature and report of a case of Progressive Non Fluent aphasia type of frontotemporal dementia , Journal of geriatric mental health 2016;3:pages 164-167.
  34. Chandra SR, Thomas Gregor Issac, Deepak S, Teja R, Kuruthukulangara S. Pyridoxine-dependent convulsions among children with refractory seizures: A 3-year follow-up study. J Pediatr Neurosci2016; 11:188-92.
  35. Chandra SR, Thomas Gregor Issac, Philip. M, Gadad. V, Creutzfeldt–Jakob disease phenotype and course: Our experience from a tertiary center. Indian J Psychol Med 2016; 38:438-442.
  36. Thomas Gregor Issac, Chandra SR. The woman who lost her words. Saudi Journal of Medical Sciences 2016; 4: 239-40.
  37. Chandra SR, Thomas Gregor Issac, Kumar V, Pai A, Patil SA. Human cysticercosis. International Journal of Health Allied Sciences 2016; 5:174-7.
  38. Chandra SR, Thomas Gregor Issac, Korada SK, Teja KV, PhilipM. Neuropsychiatric symptoms in a cohort of patients with frontotemporal dementia: Our experience. Indian J Psychol Med 2016; 38:326-30.
  39. Varghese V, Chandra SR, Christopher R, Rajeswaran J, Prasad C, Subasree R, Thomas Gregor Issac. Cognitive dysfunction in patients with Neurocysticercosis. Indian J Psychol Med 2016; 38:142-146.
  40. Thomas Gregor Issac, Chandra S.R, Rajeswaran J, Christopher R, Philip M, Demographic features and Neuropsychological correlates in a cohort of 200 patients with Vascular Cognitive Decline due to Cerebral Small Vessel disease. Indian J Psychol Med 2016; 38:127-32.
  41. Varghese V, Chandra SR, Christopher R, Rajeswaran J, Prasad C, Subasree R, Thomas Gregor Issac. Factors determining cognitive dysfunction in cerebral small vessel disease. Indian J Psychol Med 2016; 38:56-61.
  42. Chandra SR, Thomas Gregor Issac, Nagaraju BC, Philip M. A study of cortical excitability, central motor conduction, and cortical inhibition using single pulse transcranial magnetic stimulation in patients with early Frontotemporal and Alzheimer’s dementia. Indian J Psychol Med 2016;38:25-30.
  43. Thomas Gregor Issac, Chandra SR, Nagaraju BC. Transcranial magnetic stimulation (TMS) as a tool for early diagnosis and prognostication in Cortico-basal ganglia degeneration (CBD) syndromes: Review of Literature and case report. Indian J Psychol Med 2016;38:81-3.
  44. Thomas Gregor Issac, Sadandavalli Retnaswami Chandra, Rita Christopher, Jamuna Rajeswaran, and Mariamma Philip, “Cerebral Small Vessel Disease Clinical, Neuropsychological, and Radiological Phenotypes, Histopathological Correlates, and Described Genotypes: A Review,”Journal of Geriatrics, vol. 2015, Article ID 564870, 11 pages, 2015. doi:10.1155/2015/564870
  45. Chandra SR, Thomas Gregor Issac, Shivram S. Catatonia in children following systemic illness. Indian Journal of Psychological Medicine 2015; 37:pages 413-418.
  46. Prabhakar, P., Chandra, S. R., Supriya, M ,Thomas Gregor Issac, Prasad, C., & Christopher, R. Vitamin D status and vascular dementia due to cerebral small vessel disease in the elderly Asian Indian population.Journal of the Neurological Sciences,2015, 359:1, 108-111.
  47. Chandra SR, Thomas Gregor Issac, Philip M, Krishnan A, Elevated anti-measles antibody titre: An association in Autoimmune encephalitis. Journal of Neurosciences in Rural Practice 2015;6:536-540.
  48. Chandra SR, Thomas Gregor Issac, A case of mitochondrial Cytopathy with exertion induced dystonia. Journal of Pediatric Neurosciences, 2015;10:254-7.
  49. Chandra SR, Thomas Gregor Issac, Ayyappan K. New onset psychosis as the first manifestation of neuropsychiatric lupus. A situation causing diagnostic dilemma. Indian Journal of Psychological Medicine 2015;37:pages 333-338
  50. Chandra SR, Thomas Gregor Issac, Gayathri, N, Gupta, N,Abbas.M M, Atypical case of Myoclonic Epilepsy With Ragged Red Fibers (MERRF) and the lessons learned. Journal of Postgraduate Medicine 2015; 61pages 200-202.
  51. Chandra SR, Thomas Gregor Issac, Gayathri N, Shivaram S. Schwartz-Jampel syndrome. Journal of Pediatric Neurosciences 2015;Issue10:pages69-71
  52. Chandra S.R, Raj .P, Thomas Gregor Issac, Self-mutilation in Neurodegeneration with brain Iron Accumulation. Indian Journal of Dermatology 2015,Issue60,pages :290-292.
  53. Chandra SR, Thomas Gregor Issac, Rita Christopher. Letter to Editor, Clinical features and course of Glutaric Aciduria- Report of 6 cases. Journal of Neurosciences in Rural Practice, 2015, Volume 6, Issue 2, pages 290-294.
  54. Chandra S.R, Thomas Gregor Issac, Abbas M.M. Apraxias in Neurodegenerative dementias. Indian Journal of Psychological Medicine, 2015, Volume37, Issue 1, pages 42-47.
  55. Thomas Gregor Issac, Soundarya .S, Christopher R, Chandra S.R, Vitamin B12 Deficiency: An Important reversible co-morbidity in Neuropsychiatric Manifestations. Indian Journal Of Psychological Medicine 2015; Volume 37, Issue1, pages 26-29.
  56. Thomas Gregor Issac and Chandra SR, Steroid therapy: a double edged sword, Letter, Medical Science, 2014, Volume 15, Issue 61, December 2014, pages 32-33
  57. Chandra S.R, Thomas Gregor Issac, Sindhu Krishnah, Review Article, Mobile Towers, Cell Phones and its Health consequences: Facts or Fiction, TAPI Journal Vol 6 ,Issue 3, August- December 2014, pages 1-5.
  58. Chandra SR, Thomas Gregor Issac, Neurodegeneration and Mirror Image agnosia, Research letter, North American Journal Of Medical Sciences 2014;Volume 6:Issue 9: pages 472-477
  59. Chandra SR, Thomas Gregor Issac. Mirror image agnosia. Indian J Psychol Med 2014  Volume: 36 Issue: 4   Page: 400-403
  60. SR Chandra, Sahana.S, Thomas Gregor Issac; Approach to diagnosis and treatment of epilepsies; Review article; TAPI Journal Vol.6,Issue 2 ,April-July 2014 Pages 6-14..
  61. SR Chandra, Ravi Yadav,CSPuneeth, Jitender Saini, Thomas Gregor Issac; ‘The Spectrum of Vascular Dementia’ — A Retrospective Study from South India,JAPI Issue,June 2014,vol. 62 pages 498-504.
  62. Chandra SR, Seshadiri R, Chikabasavaiah Y, Issac TG; Progressive Limbic encephalopathy: Problems and Prospects. Annals of Indian Academy of Neurology 2014;17;166-170.
  63. Chandra S.R, Thomas Gregor Issac; Uncommon Manifestation in a case of Mitochondrial Cytopathy; Case Report; TAPI Journal 6,Issue 4 ,January- March 2014 Pages 11-13.
  64. Vandana V.P, Chandra S.R, Thomas Gregor Issac; Speech, Language ,Hearing and communication Disorders in Individuals with HIV/AIDS; Review Article;TAPI Journal Vol.6,Issue 4 ,January- March 2014 Pages 1-5.
  65. SR Chandra, Thomas Gregor Issac; Battered woman Syndrome-An unusual case presentation of pseudodystonia, Case report, Journal of Neurosciences in Rural practice, April –June 2014, Vol(5), Issue 2,pages 35-37.
  66. Sindhu Krishnah CS, Chandra SR, Thomas Gregor Issac, Sanjith, Radhamma H; Legal and Ethical aspects in Nursing Practice- Review article; TAPI Journal ,Vol 5, issue 3,Pages 12-15 September- December 2013.
  67. Vandana V.P, Chandra S.R, Thomas Gregor Issac; Influence of AAC modes on Speech Intelligibility in a speaker with spastic-flaccid Dysarthria due to Amyotrophic lateral Sclerosis; TAPI Journal ,Vol 5, issue 3,Pages 1-5 September- December 2013.
  68. Thomas Gregor Issac, ChandraR, Nagaraju B.C; Transcranial Magnetic Stimulation in patients with early cortical dementias: A Pilot Study. Annals of Indian Academy of Neurology 2013; 16;619-622.
  69. Clinical and Radiological Spectrum of CSF Anti-Measles Antibody associated Encephalopathy- Chandra SR, Thomas Gregor Issac, Ramakrishna A; TAPI journal Vol 5, Issue 2 ,May-august 2013; pgs1-6.
  70. Munivenkatappa A, Devi B.I, Thomas Gregor Issac, Bhat D.I, Kumaraswamy A.D, Shukla D.P; Bicycle Accident –related head injuries in India: Journal of Neurosciences in Rural practice 2013,Vol 4 pages 262-266

We are looking for highly motivated research assistants and post-doctoral fellows to work on TLSA/SANSCOG projects. Candidates with clinical/neuroscience/cognitive sciences experience and research aptitude are encouraged to apply. A minimum full-time commitment of one year is required. Candidates with MBBS, MD (Allopathic / Complementary and Alternative Systems of Medicine), PhD (Neuroscience) are strongly desirable.

If you are interested in our lab and would like to contribute to our research. Please send your CV, Cover letter in one pdf file to the Principal Investigator Dr. Thomas Gregor Issac (





Centre for Brain Research
Indian Institute of Science Campus
CV Raman Avenue
Bangalore 560012. India.

Email: thomasgregor[at]
Telephone: Office +91 80 2293 3588