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 Table of Contents    
BRIEF RESEARCH COMMUNICATION  
Year : 2021  |  Volume : 63  |  Issue : 1  |  Page : 66-69
Memory changes following adjuvant temporo-parietal repetitive transcranial magnetic stimulation in schizophrenia


1 Department of Clinical Psychology, Central Institute of Psychiatry, Ranchi, Jharkhand, India
2 Student Wellness Centre, AIIMS, New Delhi, India
3 Department of Psychiatry, Central Institute of Psychiatry, Ranchi, Jharkhand, India
4 Department of Psychiatry, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India

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Date of Submission21-May-2020
Date of Decision01-Sep-2020
Date of Acceptance23-Oct-2020
Date of Web Publication15-Feb-2021
 

   Abstract 


Objective: The use of repetitive transcranial magnetic stimulation (rTMS) in schizophrenia has shown improvement as well as deficits in memory. Though most studies had focused on dorsolateral prefrontal cortex only, but impact of rTMS on cognitive functions remain inconclusive. The need of the study is to assess the impact of rTMS on memory in schizophrenia.
Materials and Methods: Forty right-handed male patients with schizophrenia were included by purposive sampling and rated on Positive and Negative Syndrome Scale (PANSS) before starting the rTMS treatment with the experimental group. Low frequency 1 Hz rTMS including 1200 stimulations were given over temporo-parietal cortex for 20 min as add on to medications. At the end of 10 session treatment (5 days a week for 2 weeks), the patients were re-evaluated.
Results: A total of 39 patients (20 for experimental group and 19 for control group) with mean age of 29.70 ± 9.05 and 31.26 ± 7.78 years, respectively, shows significant difference to pre- and post-treatment mean PANSS score in positive, negative and general psychopathology domains. The pre- and post-treatment mean Postgraduate Institute Memory Scale Scores with multivariate repeated measures analysis of variance revealed significant improvements in all memory domains (P < 0.01) except remote memory in both experimental and control groups.
Conclusion: RTMS in combination with antipsychotics has shown improvement in psychopathology in patients of schizophrenia without any deterioration of memory.

Keywords: Memory, repetitive transcranial magnetic stimulation, schizophrenia, temporoparietal cortex

How to cite this article:
Gupta P, Sahu A, Prasad S, Sinha VK, Bakhla AK. Memory changes following adjuvant temporo-parietal repetitive transcranial magnetic stimulation in schizophrenia. Indian J Psychiatry 2021;63:66-9

How to cite this URL:
Gupta P, Sahu A, Prasad S, Sinha VK, Bakhla AK. Memory changes following adjuvant temporo-parietal repetitive transcranial magnetic stimulation in schizophrenia. Indian J Psychiatry [serial online] 2021 [cited 2021 Jul 28];63:66-9. Available from: https://www.indianjpsychiatry.org/text.asp?2021/63/1/66/309485





   Introduction Top


Cognitive deficits are one of the important factors which predict long-term outcomes in persons with schizophrenia. Specific cognitive deficits incorporates working and episodic memory, attention, language comprehension, processing speed, and executive function.[1] Apparently patients with schizophrenia might be differing with healthy control on functional integrity, organization, and activation of neuronal networks responsible for various cognitive functioning and memory.[2] Repetitive transcranial magnetic stimulation (rTMS) can be used to modulate specific brain areas, which is found to be beneficial for various neuropsychiatric conditions.[3] While with rTMS, several additional safety studies have not reported any adverse sustained changes in cognitive function,[4],[5] some studies have shown improvement in verbal memory and motor reaction times,[5],[6] decrease in the latency for picture naming.[5] However, there are reports of worsening of immediate and delayed recall.[6] The dorsolateral prefrontal cortex, left temporo-parietal areas and parietal stimulation by rTMS influences working memory by improving,[7] or may cause deterioration.[8] These functions could be verbal working memory performance,[9] or visual working memory performance.[10] Since most of these studies have been carried out in healthy, young adults, we undertook the current study to find out the effects of adjuvant left temporo-parietal rTMS on memory functions in patients with schizophrenia; with proposed null hypothesis of no effects of adjuvant rTMS on memory functions among patients of schizophrenia.


   Materials and Methods Top


This study was conducted at a tertiary care psychiatric institute by department of psychiatry and department of clinical psychology. The study protocol was approved by the institutional review board of the institute.

Forty male schizophrenia patients recruited through purposive sampling, aged between 18 and 50 years were assigned into experimental (n = 21) and control groups (n = 19) by group allocation. One patient of experimental group was prematurely discharged before completion of study, hence dropped from the study. Right handedness was assessed using Handedness Preference Schedule.[11] Those with comorbid psychiatric or neurological disorder, having metallic implants in body or treated with electroconvulsive therapy in past 6 months were excluded from the study. Patients were then rated on Positive and Negative Syndrome Scale (PANSS)[12] and Postgraduate Institute Memory Scale (PGI-MS).[13] PGI-MS is a structured verbal test standardized for Indian population. It includes tests of various domains such as attention and concentration, recent and remote memory, delayed and immediate recall, recognition of common objects, verbal retention of similar and dissimilar pairs and mental balance. Experimental group received a total of 10 rTMS sessions (5 days per week for 2 weeks) in addition to medication and after the session at day-11, a reassessment using PANSS and PGI-MS was done. Control group was not given any rTMS session but was assessed twice with the same tools before and after 2 weeks interval. All the medications that the patient received during this period were decided primarily by the treating team and the investigators were blind to it.

Motor threshold estimation

Neuropack Sigma evoked potential measuring system (Nihon Kohden, Japan) was used. The MT for the right abductor pollicis brevis was decided using a figure of eight shaped coil at 1 Hz frequency as per Rossini-Rothwell algorithm.

Stimulation procedure

Left sided 1-Hz stimulation in experimental group was provided over temporoparietal region using Magstim Rapid magnetic stimulator (Magstim Company Ltd, Whiteland, UK) with figure of eight coil in one continuous, 20 min train at 100% of the resting motor threshold delivering 1200 stimulations.

The results obtained were analyzed using the computer software program Statistical Package for Social Sciences (SPSS)-version 10.0 (SPSS for Windows, Version 10.0. Chicago, IL, SPSS Inc.). Description of sample characteristics was done with descriptive statistics-mean and standard deviation. Group differences for continuous sample characteristics were evaluated with independent t-test. To compare the overall impact of intervention over treatment time period for the two groups, a set of multivariate repeated measures analysis of variance was employed with treatment/intervention as the between-group factor and time as the within-group factor.


   Results Top


A total of 39 patients (20 for experimental group and 19 for control group) were included for the study. [Table 1] summarizes the sample characteristics with group difference. The mean age of the experimental group was 29.70 ± 9.05 years and it was 31.26 ± 7.78 for control group (t = −0.577, df = 37, P = 0.567). Similarly, across the variables of years of education, duration of illness, age of onset, duration of present episode and chlorpromazine equivalent antipsychotic dose, there was no significant group difference was found. There was significant difference in between pre- and post-treatment mean PANSS scores for both the groups [Table 1].
Table 1: Comparison of clinical variables between experimental (n=20) and control groups (n=19) and pre-post repetitive transcranial magnetic stimulation mean positive and negative syndrome scale score difference

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The mean PGI-MS Scores were assessed pre- and post-treatment and compared, with treatment there was significant improvements in all memory domains (P < 0.01) of PGIMS except remote memory in both experimental and control groups [Table 2]. None of the patients of experimental group developed any side effects of rTMS during study period.
Table 2: Effect of treatment across experimental and control groups over time: Postgraduate institute memory scale scores within subjects (n=39)

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   Discussion Top


This study intended to assess impact of rTMS on the left temporo-parietal region on cognitive functions such as executive and memory functioning and psychopathology among patients of schizophrenia. There was equally and significant improvement of most of the cognitive functions (except for remote memory) in both experimental and control group. However, there was significant improvement in both experimental and control group as pre- to post-PANSS score; but most importantly posttreatment mean PANSS score of experimental group was significantly lower than control group. This can be implicated for favoring adjunctive use of rTMS for better and faster response in schizophrenia. This beneficial effects is in accordance to a study in which low frequency rTMS over temporo-parietal region was used for the treatment of auditory hallucinations in recent onset schizophrenia[14] and other similar studies.[15],[16]

In our study, rTMS stimulation were provided over temporo-parietal region with a slow rate (1 Hz), against other studies examining rTMS in schizophrenia, in which, to assess the cognitive functioning, rapid rate stimulation was given primarily over dorsolateral prefrontal region.[17],[18] Low frequency stimulation of tempero-parietal region was used in this study in accordance with the existing evidence for treating psychosis having auditory verbal hallucinations as a prominent symptoms.[19] The fronto-temporal-limbic dysfunction hypothesis, is based on functional imaging studies and many other studies.[20],[21] It attributes disconnection of hippocampus with prefrontal cortical areas for neuropsychological dysfunction in schizophrenia.

Delivering low frequency rTMS over the ipsilateral parietal lobe prior to task execution, results into improvement in attention to a visual task.[22] The present study findings are similar to studies which have investigated the effect of rTMS on various cognitive functions especially memory in disorders like depression and schizophrenia.[23] It ought to likewise be noticed that despite improvement in task performance presented by most of the patients, they remained within dysfunction limit, strengthening the notion that there are continuing cognitive deficits in association with psychosis.[24] Thus impairment in cognition is a reflection of a supposedly more deteriorative course in schizophrenia.

The role of antipsychotics cannot be excluded in beneficial effects of rTMS, it is conceivable that the absence of significant differences in direct comparison between the two groups could be an outcome of the generally modest sample size prompting a Type II error. Still, we can conclude that rTMS in combination with antipsychotics has shown statistically significant clinical effect on the treatment of psychopathology without any deterioration of memory. This positive effect on memory further taken as good effect of rTMS in schizophrenia.

Limitation includes lack of sham rTMS in control group, sample consisted of male patients only, continuation of conventional pharmacotherapy and doses is a major confounding factor in the interpretation of results. Due to low and short stimulation parameters there may be absence of evidence for cognitive deterioration, hence in future larger sample size with longer duration of rTMS treatment should be considered.


   Conclusion Top


We observed no adverse effect of rTMS on memory functioning, but significant positive effect of rTMS on psychopathology of schizophrenia.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Fioravanti M, Bianchi V, Cinti ME. Cognitive deficits in schizophrenia: An updated metanalysis of the scientific evidence. BMC Psychiatry 2012;12:64.  Back to cited text no. 1
    
2.
Fornito A, Zalesky A, Pantelis C, Bullmore ET. Schizophrenia, neuroimaging and connectomics. Neuroimage 2012;62:2296-314.  Back to cited text no. 2
    
3.
Mishra BR, Sarkar S, Praharaj SK, Mehta VS, Diwedi S, Nizamie SH. Repetitive transcranial magnetic stimulation in psychiatry. Ann Indian Acad Neurol 2011;14:245-51.  Back to cited text no. 3
[PUBMED]  [Full text]  
4.
Speer AM, Repella JD, Figueras S, Demian NK, Kimbrell TA, Wasserman EM, et al. Lack of adverse cognitive effects of 1 Hz and 20 Hz repetitive transcranial magnetic stimulation at 100% of motor threshold over left prefrontal cortex in depression. J ECT 2001;17:259-63.  Back to cited text no. 4
    
5.
Wassermann EM, Blaxton TA, Hoffman EA, Berry CD, Oletsky H, Pascual-Leone A, et al. Repetitive transcranial magnetic stimulation of the dominant hemisphere can disrupt visual naming in temporal lobe epilepsy patients. Neuropsychologia 1999;37:537-44.  Back to cited text no. 5
    
6.
Loo CK, Mitchell PB, McFarquhar TF, Malhi GS, Sachdev PS. A sham-controlled trial of the efficacy and safety of twice-daily rTMS in major depression. Psychol Med 2007;37:341-9.  Back to cited text no. 6
    
7.
Chung SW, Sullivan CM, Rogasch NC, Hoy KE, Bailey NW, Cash RFH, et al. The effects of individualised intermittent theta burst stimulation in the prefrontal cortex: A TMS-EEG study. Hum Brain Mapp 2019;40:608-27.  Back to cited text no. 7
    
8.
Mottaghy FM, Gangitano M, Krause BJ, Pascual-Leone A. Chronometry of parietal and prefrontal activations in verbal working memory revealed by transcranial magnetic stimulation. Neuroimage 2003;18:565-75.  Back to cited text no. 8
    
9.
Albouy P, Weiss A, Baillet S, Zatorre RJ. Selective entrainment of theta oscillations in the dorsal stream causally enhances auditory working memory performance. Neuron 2017;94:193-206.e5.  Back to cited text no. 9
    
10.
Juan CH, Tseng P, Hsu TY. Elucidating and modulating the neural correlates of visuospatial working memory via noninvasive brain stimulation. Curr Dir Psychol Sci 2017;26:165-73.  Back to cited text no. 10
    
11.
Mandai MK, Pandey G, Singh SK, Asthana HS. Hand preference in India. Int J Psychol 1992;27:433-42.  Back to cited text no. 11
    
12.
Kay SR, Fiszbein A, Opler LA. The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophr Bull 1987;13:261-76.  Back to cited text no. 12
    
13.
Persad D, Wig NN. The Construction and Standardization of Clinical Test of Memory in Simple Hindi. Agra: National Psychological Cooperation; 1997.  Back to cited text no. 13
    
14.
Ray P, Sinha VK, Tikka SK. Adjuvant low-frequency rTMS in treating auditory hallucinations in recent-onset schizophrenia: A randomized controlled study investigating the effect of high-frequency priming stimulation. Ann Gen Psychiatry 2015;14:8.  Back to cited text no. 14
    
15.
Jandl M, Bittner R, Sack A, Weber B, Günther T, Pieschl D, et al. Changes in negative symptoms and EEG in schizophrenic patients after repetitive transcranial magnetic stimulation (rTMS): An open-label pilot study. J Neural Transm (Vienna) 2005;112:955-67.  Back to cited text no. 15
    
16.
Holi MM, Eronen M, Toivonen K, Toivonen P, Marttunen M, Naukkarinen H. Left prefrontal repetitive transcranial magnetic stimulation in schizophrenia. Schizophr Bull 2004;30:429-34.  Back to cited text no. 16
    
17.
Nahas Z, Lomarev M, Roberts DR, Shastri A, Lorberbaum JP, Teneback C, et al. Unilateral left prefrontal transcranial magnetic stimulation (TMS) produces intensity-dependent bilateral effects as measured by interleaved BOLD fMRI. Biol Psychiatry 2001;50:712-20.  Back to cited text no. 17
    
18.
Rollnik JD, Huber TJ, Mogk H, Siggelkow S, Kropp S, Dengler R, et al. High frequency repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex in schizophrenic patients. Neuroreport 2000;11:4013-5.  Back to cited text no. 18
    
19.
Slotema CW, Blom JD, van Lutterveld R, Hoek HW, Sommer IE. Review of the efficacy of transcranial magnetic stimulation for auditory verbal hallucinations. Biol Psychiatry 2014;76:101-10.  Back to cited text no. 19
    
20.
Taylor SF, Kornblum S, Lauber EJ, Minoshima S, Koeppe RA. Isolation of specific interference processing in the Stroop task: PET activation studies. Neuroimage 1997;6:81-92.  Back to cited text no. 20
    
21.
Perlstein WM, Carter CS, Barch DM, Baird JW. The Stroop task and attention deficits in schizophrenia: A critical evaluation of card and single-trial Stroop methodologies. Neuropsychology 1998;12:414-25.  Back to cited text no. 21
    
22.
Hilgetag CC, Théoret H, Pascual-Leone A. Enhanced visual spatial attention ipsilateral to rTMS-induced 'virtual lesions' of human parietal cortex. Nat Neurosci 2001;4:953-7.  Back to cited text no. 22
    
23.
Kirova AM, Bays RB, Lagalwar S. Working memory and executive function decline across normal aging, mild cognitive impairment, and Alzheimer's disease. Biomed Res Int 2015;2015:748212.  Back to cited text no. 23
    
24.
Addington J, Saeedi H, Addington D. The course of cognitive functioning in first episode psychosis: Changes over time and impact on outcome. Schizophr Res 2005;78:35-43.  Back to cited text no. 24
    

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Correspondence Address:
Ajay Kumar Bakhla
Department of Psychiatry, Rajendra Institute of Medical Sciences, Ranchi - 834 009, Jharkhand
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/psychiatry.IndianJPsychiatry_532_20

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