Impaired Sustained Attention in Patients with Subclinical Hypothyroidism

  • August 2025,
  • 45;
  • DOI: https://doi.org/10.3121/cmr.2025.1925

Abstract

Background: Subclinical hypothyroidism (SCH) is of particular importance due to its high prevalence and its association with cognitive deficits. Patients often express complaints of neuropsychological symptoms and cognitive impairments including lack of attention. Also, patients treated with levothyroxine (LT-4) often report persistent complaints related to mental slowing or lack of attention despite normal TSH levels.

Purpose: To investigate the effects of different ranges of TSH on sustained attention in SCH.

Methods: Included in the study were 136 participants that were divided into four groups: Group 1, 35 healthy individuals; Group 2, 33 newly diagnosed patients with SCH; Group 3, 36 patients on LT-4 with uncontrolled or elevated TSH; Group 4, 32 euthyroid patients (ongoing LT-4). Laboratory measurements and clinical assessment were done. Rapid visual processing (RVP) task was performed on standardized battery (Cambridge Automated Neuropsychological Test Battery).

Results: There was significant impairment in sustained attention (P=<0.05) in Group 2 patients who had neuropsychological symptoms and SCH diagnosed with a TSH range of ≥2.5mIU/L.

Conclusion: Our findings encourage screening for sustained attention along with thyroid profile in those who report neuropsychological symptoms. TSH mean range of ≥2.5 mIU/L was established as a more reasonable threshold for evaluating sustained attention and initiating LT-4 in SCH.

Keywords:

Thyroid stimulating hormone (TSH) plays a crucial role in preserving optimal cognitive function. It is postulated that the influence of TSH extends to the synthesis and degradation of neurotransmitters such as norepinephrine, dopamine, and choline.1,2 These neurotransmitters are also essential for controlling how the attention networks perform. Numerous imaging studies3–6 have demonstrated, using neuropsychological tests, that subclinical hypothyroidism (SCH) is associated with deficits of cognitive domains such as memory, inhibition, and attention. SCH is defined as an elevated serum TSH level, with a normal total or free triiodothyronine (FT3) and free thyroxine (FT4).7

Researchers using positron emission tomography have discovered patients with hypothyroidism have decreased cerebral blood flow and localized activity in brain regions associated with cognitive functions.8,9 Kumar and colleagues10 demonstrated one possible cause of the impairment of attention and cognitive abilities in patients with SCH may be changes in intrinsic resting-state functional connectivity in the somatomotor and right frontoparietal attention networks. Another study reported the results of the phasic alertness test, which showed patients with hypothyroidism had trouble remaining vigilant for extended periods of time.11 Additionally, research discovered these patients self-rate as less focused and attentive.12

These findings suggest patients with SCH had attention deficits, although it is unclear at what range of TSH these deficits appear. In euthyroid patients, despite normal TSH levels, associations between fluctuations in TSH and neuropsychological symptoms or cognitive impairments have been noted in the existing literature.13 The potential enhancements in sustained attention among patients undergoing levothyroxine (LT-4) treatment are often unheeded, even as some patients persist in exhibiting deficits even after their TSH levels return to the normal range, indicating a prolonged impact on cognitive function due to prior abnormal TSH levels. A study highlighted that individuals with TSH levels ≤4.0mIU/L, in the absence of symptoms, are typically considered euthyroid.14 However, if neuropsychological symptoms are present, initiating LT-4 treatment may be warranted at a lower cut-off value of TSH, specifically 2.5 mIU/L.15 Furthermore, Hayashi et al.16 proposed a delineation of TSH levels, with the range of 0.45-4.49 mIU/L, indicative of euthyroidism in asymptomatic individuals, while TSH levels between 4.5-19.9 mIU/L, accompanied by normal free thyroxine (fT4) levels within the reference range (5.0 to 12.0 μg/dL), are categorized as SCH. Given this context, it is imperative to assess patients within these TSH ranges to ascertain the presence of attention deficits in individuals with SCH. Hence, the present study was structured to examine the impairment of visual sustained attention in SCH across various ranges of TSH levels, and to evaluate whether these deficits ameliorate with LT-4 treatment. Even though the study was intended to be cross-sectional, the duration that patients received LT-4 treatment was taken into account to investigate the impact on sustained attention. Thus, the present study aimed to investigate sustained attention abilities in distinct groups, including patients with elevated TSH levels (≥4.0 mIU/L) and euthyroid individuals (TSH <4.0 mIU/L), compared with newly identified cases (TSH ≥2.5 mIU/L) and healthy individuals.

Methods and Materials

Participants

We studied 101 patients from the multiple health centers of the city: Medical out-patient department of the Shri Guru Ramdas Hospital; Health Centre of Guru Nanak Dev University; Medical out-patient department of Apollo Hospital. Additionally, patients were contacted by neighborhood general practitioners. Every consulting physician gave their written consent before beginning the recruitment process of patients. We recruited 35 healthy volunteers from the local community. They had normal thyroid function testing and did not exhibit any thyroid dysfunction symptoms. Also, they had no known neurological diseases, cardiovascular problems, or other untreated chronic ailments.

Procedure

This cross-sectional study was approved by the Institutional Ethics Committee of Guru Nanak Dev University, Amritsar, and the procedure was registered under Clinical Trial Registry of India CTRI/2022/04/042319. The Helsinki Declaration of 2013 was followed in conducting the study, and all participants provided written informed consent to guarantee their voluntary involvement in the study.

The sample size was calculated with the help of G* Power (3.1.9.2), where values of ρ1 (proportion of cognitive dysfunction in SCH cases =0.36); ρ2 (proportion of cognitive dysfunction in healthy cases= 0.14);17 elderly Indian patients (>60 years α = 0.05 (absolute error), and β = 0.90. The estimated sample size was 136.

Clinical Evaluation and Serum Measurements

The thyroid functions of every participant were assessed both clinically and biochemically. Medical comorbidities, a patient’s history of mental illnesses, their familiarity with mental disorders, and their concurrent use of therapy (medication, both psychiatric and nonpsychiatric) were all recorded. The patients’ medical histories disclosed the existence of any ongoing treatment regimen consisting of specific dosages of levothyroxine (L-T4), together with information about the length of the course of treatment, thyroid replacement history, and neuropsychological symptoms.

Based on what was seen in the clinic, the patients were split into three categories:

  1. Individuals who were just been diagnosed and showing neuropsychological symptoms.

  2. Patients who had been diagnosed already but were either dealing with symptoms of hypothyroidism or had TSH levels that were not well controlled.

  3. Patients who were keeping up with their appointments and managing their medications well to keep their TSH levels normal.

Groups of the study were classified as: Group 1, Healthy Controls; Group 2, newly diagnosed patients with TSH levels ≥ 2.5mU/L presenting with neuropsychological symptoms; Group 3, patients with TSH levels ≥4.0mIU/L (ongoing L-T4 treatment); and Group 4, Euthyroid patients with TSH levels <4.0mIU/L but with ongoing LT-4 treatment.

The global cognitive status was assessed using the Mini Mental State Examination (MMSE). The maximum score on the MMSE is 30. There are three categories to determine the severity of cognitive impairment: 0–17 represents severe cognitive impairment, 18–23 represents mild cognitive impairment, and 24–30 represents no cognitive impairment.18 Patients were eligible for enrollment in the study if they attained a score of 24.19,20 Further, the modified version of the Kuppuswamy Scale was used for the evaluation of socioeconomic status.21 The total score ranges from 3 to 29. It categorizes the families into five different groups: “upper class (I), upper middle class (II), lower middle class (III), upper lower (IV), and lower socio-economic class (V) on the basis of: (a) occupation of the head of the family; (b) education of the head of the family; and (c) total monthly income of the family. Education level was noted for each participant: level 1, left formal education before age 16; level 2, left formal education at age 16; level 3, left formal education at age 17–18; level 4, undergraduate degree or equivalent; level 5, master’s degree or equivalent; and level 6, PhD or equivalent.

Examination of Visual Sustained Attention

All the study participants were administered the computerized neuropsychological test for visual sustained attention from the Cambridge Neuropsychological Test Automated Battery (CANTAB). The Rapid Visual Processing (RVP) task was employed. The evaluation of the battery performance was conducted in a controlled and noise free environment, specifically a quiet room. Participants were seated at a comfortable seat height and handed the CANTAB-I pad (Cambridge Cognition Ltd, 2012) to carry out the RVP task by placing responses on a touch screen. Digits (ranging from 2 to 9) appeared one at a time (100 digits/min) in the center of the screen in a random order. Participants were asked to press a response pad when they detected any one of three number sequences (3–5–7, 2–4–6, 4–6–8).

The following variables of the RVP task were recorded: RVP Response latency (mean)-the mean response latency of a correct response to a target sequence, calculated across all assessed blocks; RVP A′: A′ (A prime) was the signal detection measure of sensitivity to the target, regardless of response tendency (expected range 0.000 to 1.000; bad to good). In essence, this metric was a measure of how good the subject was at detecting target sequences; RVP probability of hit: the probability of responding to a target sequence within the response window during the assessed phase; RVP probability of false alarm: the probability of an incorrect response being made in the assessed phase; RVP total misses: the total number of target sequences that were not responded to within the response window.

Statistical Analysis

Statistical analysis was done using SPSS version 27.0 (IBM SPSS Statistics for Windows, [IBM Corp., Armonk, NY. USA]). Descriptive statistics were used to describe the clinical characteristics of the study participants. Normality of the data was analyzed with the Kolmogorov Smirnov test. Due to the violation of the assumptions of normality of variance, a non-parametric test was employed. Between group comparisons was done by using the Kruskal Wallis test for the outcome variables of RVP task. Further we performed the Dunn test, post hoc pairwise multiple comparisons for significant differences with the Bonferroni correction to examine the differences in the key parameter RVP probability of hit score among all four groups of the study. Next, a linear regression model was employed for the variables of RVP task, wherein covariates such as age, level of education, and socioeconomic status were included as independent variables. Furthermore, to examine whether the duration of LT-4 treatment influences the performance in sustained attention, we divided Group 4 (euthyroid) on LT-4 treatment into 4a (having LT-4 for 1 or more than one year) and 4b (having LT-4 for 10 or more than 10 years), wherein a probability of hit score was used for the analysis. The sample size was estimated with the help of G* Power (3.1.9.2). ρ1 ( proportion of cognitive dysfunction in SCH cases =0.36); ρ2 (proportion of cognitive dysfunction in healthy cases= 0.14)17 elderly Indian patients (>60 years; α = 0.05 (absolute error) and β = 0.90.

Results

There were 136 participants involved in the study: 35 healthy individuals, and 101 patients diagnosed with SCH. Demographics and clinical characteristics of all the participants are shown in Table 1. The level of education for 61% of participants was undergraduate or equivalent, and 79.4% of participants belonged to the upper middle class in terms of socioeconomic status. The analysis of comparison among RVP task variables between groups reveals statistically significant (P<0.05) differences (Table 2). Groups 3 and 4 had lower total misses, a higher probability of hitting, and a shorter mean latency than healthy controls. But Group 2 patients had higher total misses, a lower probability of hitting, and a lower target A′ sensitivity score than healthy controls. Strong evidence of a difference (P<0.05) between the mean ranks of at least one pair of groups was found using a Kruskal-Wallis test. All six pairings of groups underwent Dunn’s pairwise testing. A significant difference (P=0.014, adjusted for the Bonferroni correction) was seen between the Group 2 patients with neuropsychological symptoms (TSH≥2.5mIU/L) and the group 4 euthyroid patients (on LT-4 treatment). Group 2 had a median probability of a hit score of 53.50, while the euthyroid group had a median score of 83.09. There was lack of evidence indicating distinctions among the remaining pairs. Findings of the linear regression model analysis of impact of covariates on dependent variables are shown in Table 3. The level of education of the study participants significantly influenced the results of the key variables of the RVP task. A significant result was obtained in the probability of hit score; the 4b group had higher scores as compared to 4a, which indicates there was better performance in sustained attention in the SCH population with the reduction in TSH levels after 10 years of LT-4 treatment. Group 4a had better scores than healthy controls, see Figure 1.

View this table:
Table 1.

Descriptive analysis of clinical characteristics of the participants

View this table:
Table 2.

Comparison of Rapid Visual Processing (RVP) task variables among all groups

View this table:
Table 3.

Analysis of regression linear model for covariates (tests of between subjects effect), N=136

Mean of probability of hit score. [† mean ± standard deviation of TSH levels; Group 1, healthy controls; Group 2, newly diagnosed patients; Group 3, patients with elevated TSH (ongoing LT-4); Group 4a, euthyroid (on LT-4 since 1 or more than 1 year); Group 4b, euthyroid (on LT-4 for 10 or more years); *statistically significant (P≤0.05)].
Figure 1.

Mean of probability of hit score. [† mean ± standard deviation of TSH levels; Group 1, healthy controls; Group 2, newly diagnosed patients; Group 3, patients with elevated TSH (ongoing LT-4); Group 4a, euthyroid (on LT-4 since 1 or more than 1 year); Group 4b, euthyroid (on LT-4 for 10 or more years); *statistically significant (P≤0.05)].

Discussion

The present study investigated the manifestation of sustained attention deficits within the population diagnosed with SCH. To ensure the standardization of testing procedures, we employed a computerized battery equipped with touchscreen technology. The CANTAB-RVP task was used to assess sustained attention within a controlled and noise-free environment. Patients in Groups 3 and 4 exhibited a reduced total number of misses, a higher probability of hits, and shorter mean latency compared to the control group. These findings indicate both groups of patients with SCH who were on LT-4 treatment—group 3 with a mean TSH of 13.5±19.7 mIU/L and group 4 with a mean TSH of 2.42±0.95 mIU/L—performed better on the RVP task as compared to healthy controls. Yuan et al.6 corroborated our findings that there were no changes in the attention networks among patients with SCH (mean TSH 12.72 ± 17.27 mIU/L). However, their results indicate there is impaired attention in patients with clinical hypothyroidism (mean TSH 101± 49.81 mIU/L. Another study of patients with SCH (mean TSH of 6.1 mIU/L) found there was no impairment in focused attention.22 Moreover, this has also been supported by other authors who found that individuals with hypothyroidism may experience enhancements in their reaction times following treatment with thyroid hormones.23,24

Additionally, it has been posited that thyroid hormone augments both the quantity and functionality of β-adrenergic receptors, thereby potentially enhancing attention and vigilance through stimulation of the catecholaminergic system.25,26 It was fascinating to consider the possibility that TSH might have a subtle impact on attention networks. On the other hand, patients in Group 2 presented with neuropsychological symptoms with a mean TSH of 4.04±1.40 mIU/L and had higher total misses, a lower probability of hitting, and a lower target A′ sensitivity score than healthy controls. Moreover, difficulties with attention could make it harder for someone to redirect their focus and use effective coping strategies when facing negative emotions. This could potentially worsen their neuropsychological symptoms.27

Functional imaging studies of the RVP task demonstrate that cognitive processing is facilitated by two distinct and autonomous brain circuits.28 The efficacy of sustained attention correlates with the activity of the right frontoparietal network, whereas left frontal activation is associated with working memory function.29 The influence of scopolamine and nicotine on the performance of the RVP task suggests a connection between task performance and the cholinergic pathway.30 Two preceding imaging investigations delineated cerebral perfusion deficits in euthyroid Hashimoto’s thyroiditis (HT) patients.31,32 Notably, Piga et al.31 observed hypoperfusion in the frontal lobe. The decline in executive functioning observed in HT may coincide with structural modifications in the left inferior frontal gyrus (LIFG). Consequently, impaired sustained attention and response inhibition in a subset of HT patients might stem from both functional and structural changes, particularly within the LIFG.33

Another noteworthy finding that emerged from the current study was that the probability of hit score exhibited significantly better results in euthyroid patients (9 out of 32 cases) undergoing LT-4 treatment for a duration of 10 years or more with a mean TSH of 1.63 mIU/L. compared to those who were having LT-4 for one or more years with a mean TSH of 2.72 mIU/L. However, in a randomized clinical trial conducted by Goyal et al.,20 an improvement in sustained attention was observed in the letter cancellation task when patients with a mean age of 31.67±8.40 years achieved a euthyroid state (TSH 3.4±0.19 mIU/L) after 3 months of LT-4 treatment. In contrast, certain studies have suggested LT-4 lacks efficacy in enhancing sustained attention. Parle and colleagues34 documented that TSH levels decreased after 6 months (median 4.0 mIU/L) and a year (median 3.7 mIU/L) in patients with SCH (mean age 73.5± 6.2 years); however, no significant improvement was seen in the subtest of sustained attention when evaluated on MEAMS (Middlesex Elderly Assessment of Mental State). Another study by Jordy and colleagues35 reported there was no significant effect of LT-4 treatment on attention after a year on the subtest of the Digit span forward and backward test in patients with a mean age of 61.6±11.5 years; whereas, decrements in TSH levels (with a mean of 1.52 ± 1.51 mIU/L) were seen. Also, an observational study by Wekking et al.36 found impaired attention by using the Paced Auditory Serial Addition Task in euthyroid females receiving LT-4 with a TSH median value of 1.4 mIU/L and a mean age of 47.8± 9.8 years. The variations observed among studies regarding the impact of LT-4 treatment on sustained attention within the SCH population may stem from differences in the age demographics of the participants and different tools used for assessment.

As shown by our findings, the participants’ specified socioeconomic status and level of education had an impact on dependent variables. These findings are consistent with the conclusion that formal educational attainment is a key measure of socioeconomic inequality, and it strongly influences brain health.37,38 Also, higher functional connectivity in pertinent brain hubs, including the orbitofrontal, posterior cingulate, and precuneus, was linked to more years of education. Integrating information, social cognition, and memory retrieval, all important tasks for preserving brain health, require these domains.39

Our findings advocate for early screening of sustained attention alongside TSH examination in patients exhibiting neuropsychological symptoms. Initiating treatment at a TSH threshold value of 2.5 mIU/L may be considered advantageous compared to adopting a conservative “wait-and-watch” approach.

While this observational study contributes valuable insights into the impairment of sustained attention among Group 2 who had neuropsychological symptoms (fatigue, memory problems, insomnia, depressive symptoms) as well as the potential enhancement associated with LT-4 treatment, further validation through extensive randomized clinical trials incorporating additional follow-up measures is warranted to substantiate these findings.

Limitations

The study design is cross-sectional, which may introduce potential selection bias in the study population and limit the ability to establish a clear relationship between the parameters of the RVP task and TSH ranges. Additionally, the lack of follow-up for patients is a significant limitation that may impact the generalizability of the results.

Conclusion

Our study concludes there is a notable reduction in sustained attention among Group 2 (newly diagnosed cases of SCH) having neuropsychological symptoms with TSH mean range ≥2.5 mIU/L. However, LT-4 treatment significantly enhances the performance of sustained attention in euthyroid patients (TSH <4.0 mIU/L) and patients with elevated TSH (≥4.0 mIU/L).

Acknowledgements

We acknowledge our thanks to Dr. Pankaj Agarwal, Senior Consultant, Apollo Hospital, Amritsar who agreed to provide information regarding patients. We extended our thanks to the patients recruited in the study.

Footnotes

  • Declarations: The authors declare no conflict of interest or funding related to this work presented in this paper.

  • Author Contributions:

    SKJ, conceptualization, drafting, data collection, data analysis & interpretation; SS, conceptualization, methodology, review and editing; AS, data collection, review and editing; APS, methodology and proof reading.

  • Received April 9, 2024.
  • Revision received May 17, 2025.
  • Accepted June 10, 2025.

References

  1. 1.
    ↵
    Accorroni A, Chiellini G, Origlia N. Effects of Thyroid Hormones and their Metabolites on Learning and Memory in Normal and Pathological Conditions. Curr Drug Metab. 2017;18(3):225-236. doi:10.2174/1389200218666170116112407
    Google ScholarCrossRefPubMed
  2. 2.
    ↵
    Pirahanchi Y, Toro F, Jialal I. Physiology, Thyroid Stimulating Hormone. In: StatPearls. Treasure Island (FL): StatPearls Publishing; May 1, 2023.
    Google Scholar
  3. 3.
    ↵
    Pasqualetti G, Pagano G, Rengo G, Ferrara N, Monzani F. Subclinical Hypothyroidism and Cognitive Impairment: Systematic Review and Meta-Analysis. J Clin Endocrinol Metab. 2015;100(11):4240-4248. doi:10.1210/jc.2015-2046
    Google ScholarCrossRefPubMed
  4. 4.
    Resta F, Triggiani V, Barile G, Subclinical hypothyroidism and cognitive dysfunction in the elderly. Endocr Metab Immune Disord Drug Targets. 2012;12(3):260-267. doi:10.2174/187153012802002875
    Google ScholarCrossRefPubMed
  5. 5.
    Yin J, Xie L, Luo D, Changes of Structural and Functional Attention Control Networks in Subclinical Hypothyroidism. Front Behav Neurosci. 2021;15:725908. doi:10.3389/fnbeh.2021.725908
    Google ScholarCrossRefPubMed
  6. 6.
    ↵
    Yuan L, Luan D, Xu X, Altered attention networks in patients with thyroid dysfunction: A neuropsychological study. Horm Behav. 2020;121:104714. doi:10.1016/j.yhbeh.2020.104714
    Google ScholarCrossRef
  7. 7.
    ↵
    Alokley A, ALNasser MN, Alabdulqader RA, Effectiveness of low dose thyroxine in patients with subclinical hypothyroidism and migraine; systematic review and meta-analysis. BMC Neurol. 2025;25(1):198. doi:10.1186/s12883-025-04214-4
    Google ScholarCrossRefPubMed
  8. 8.
    ↵
    Fani L, Roa Dueñas O, Bos D, Thyroid Status and Brain Circulation: The Rotterdam Study. J Clin Endocrinol Metab. 2022;107(3):e1293-e1302. doi:10.1210/clinem/dgab744
    Google ScholarCrossRefPubMed
  9. 9.
    ↵
    Jamatia SNN, Debbarma A, Debbarma M, Cognitive function in hypothyroid patients: a tertiary care-based cross-sectional study. International Journal of Research in Medical Sciences. 2024;12(10):3794–8.
    Google Scholar
  10. 10.
    ↵
    Kumar M, Modi S, Rana P, Alteration in intrinsic and extrinsic functional connectivity of resting state networks associated with subclinical hypothyroid. J Neuroendocrinol. Published online March 5, 2018. doi:10.1111/jne.12587
    Google ScholarCrossRef
  11. 11.
    ↵
    Constant EL, Adam S, Seron X, Bruyer R, Seghers A, Daumerie C. Anxiety and depression, attention, and executive functions in hypothyroidism. J Int Neuropsychol Soc. 2005;11(5):535-544. doi:10.1017/S1355617705050642
    Google ScholarCrossRefPubMedWeb of Science
  12. 12.
    ↵
    Burmeister LA, Ganguli M, Dodge HH, Toczek T, DeKosky ST, Nebes RD. Hypothyroidism and cognition: preliminary evidence for a specific defect in memory. Thyroid. 2001;11(12):1177-1185. doi:10.1089/10507250152741037
    Google ScholarCrossRefPubMedWeb of Science
  13. 13.
    ↵
    Beydoun MA, Beydoun HA, Rostant OS, Thyroid hormones are associated with longitudinal cognitive change in an urban adult population. Neurobiol Aging. 2015;36(11):3056-3066. doi:10.1016/j.neurobiolaging.2015.08.002.
    Google ScholarCrossRefPubMed
  14. 14.
    ↵
    Samuels MH. Psychiatric and cognitive manifestations of hypothyroidism. Curr Opin Endocrinol Diabetes Obes. 2014;21(5):377-383. doi:10.1097/MED.0000000000000089
    Google ScholarCrossRef
  15. 15.
    ↵
    Talaei A, Rafee N, Rafei F, Chehrei A. TSH cut off point based on depression in hypothyroid patients. BMC Psychiatry. 2017;17(1):327. doi:10.1186/s12888-017-1478-9
    Google ScholarCrossRefPubMed
  16. 16.
    ↵
    Hayashi T, Hasegawa T, Kanzaki H, Subclinical hypothyroidism is an independent predictor of adverse cardiovascular outcomes in patients with acute decompensated heart failure. ESC Heart Fail. 2016;3(3):168-176. doi:10.1002/ehf2.12084
    Google ScholarCrossRefPubMed
  17. 17.
    ↵
    Kaur H, Malhotra N, Jacob JJ. Impact of subclinical hypothyroidism on cognitive functions among the elderly. Aging and Health Research. 2021;1(2):100014. doi:10.1016/j.ahr.2021.100014
    Google ScholarCrossRef
  18. 18.
    ↵
    Ong HL, Subramaniam M, Abdin E, Performance of Mini-Mental State Examination (MMSE) in long-stay patients with schizophrenia or schizoaffective disorders in a psychiatric institute. Psychiatry Res. 2016;241:256-262. doi:10.1016/j.psychres.2016.04.116
    Google ScholarCrossRefPubMed
  19. 19.
    ↵
    Allam M, Helmy S, Fathy S, Moustafa A, Ginina AM, Kisk NA, Screening for Cognitive Dysfunction in Patients with Hypothyroidism. 2008;45.
    Google Scholar
  20. 20.
    ↵
    Goyal S, Dixit A, Vaney N, Madhu SV. Cognitive Status in Hypothyroid Patients Before & After Attainment of Euthyroid State. Indian Journal of Physiology and Pharmacology. 2018;62(1):113-119. Available at: https://www.ijpp.com/IJPP%20archives/2018_62_1/113-119.pdf
    Google Scholar
  21. 21.
    ↵
    Saleem SM, Jan SS. Modified Kuppuswamy socioeconomic scale updated for the year 2021. Indian Journal of Forensic and Community Medicine. 2021 Apr 28;8(1):1–3. https://doi.org/10.18231/j.ijfcm.2021.001
    Google Scholar
  22. 22.
    ↵
    Correia N, Mullally S, Cooke G, Evidence for a specific defect in hippocampal memory in overt and subclinical hypothyroidism. J Clin Endocrinol Metab. 2009;94(10):3789-3797. doi:10.1210/jc.2008-2702
    Google ScholarCrossRefPubMedWeb of Science
  23. 23.
    ↵
    Dugbartey AT. Neurocognitive aspects of hypothyroidism. Arch Intern Med. 1998;158(13):1413-1418. doi:10.1001/archinte.158.13.1413
    Google ScholarCrossRefPubMedWeb of Science
  24. 24.
    ↵
    Osterweil D, Syndulko K, Cohen SN, Cognitive function in non-demented older adults with hypothyroidism. J Am Geriatr Soc. 1992;40(4):325-335. doi:10.1111/j.1532-5415.1992.tb02130.x
    Google ScholarCrossRefPubMedWeb of Science
  25. 25.
    ↵
    Baldini M, Colasanti A, Orsatti A, Airaghi L, Mauri MC, Cappellini MD. Neuropsychological functions and metabolic aspects in subclinical hypothyroidism: the effects of L-thyroxine. Prog Neuropsychopharmacol Biol Psychiatry. 2009;33(5):854-859. doi:10.1016/j.pnpbp.2009.04.009
    Google ScholarCrossRefPubMed
  26. 26.
    ↵
    Baldini IM, Vita A, Mauri MC, Psychopathological and cognitive features in subclinical hypothyroidism. Prog Neuropsychopharmacol Biol Psychiatry. 1997;21(6):925-935. doi:10.1016/s0278-5846(97)00089-4
    Google ScholarCrossRefPubMed
  27. 27.
    ↵
    Zhao S, Du Y, Zhang Y, Gray matter reduction is associated with cognitive dysfunction in depressed patients comorbid with subclinical hypothyroidism. Front Aging Neurosci. 2023;15:1106792. doi:10.3389/fnagi.2023.1106792
    Google ScholarCrossRefPubMed
  28. 28.
    ↵
    Bussing R, Zima BT, Gary FA, Garvan CW. Barriers to detection, help-seeking, and service use for children with ADHD symptoms. J Behav Health Serv Res. 2003;30(2):176-189. doi:10.1007/BF02289806.
    Google ScholarCrossRefPubMedWeb of Science
  29. 29.
    ↵
    Coull JT, Frith CD, Frackowiak RS, Grasby PM. A fronto-parietal network for rapid visual information processing: a PET study of sustained attention and working memory. Neuropsychologia. 1996;34(11):1085-1095. doi:10.1016/0028-3932(96)00029-2
    Google ScholarCrossRefPubMedWeb of Science
  30. 30.
    ↵
    Wesnes K, Warburton DM. Effects of scopolamine and nicotine on human rapid information processing performance. Psychopharmacology (Berl). 1984;82(3):147-150. doi:10.1007/BF00427761
    Google ScholarCrossRefPubMed
  31. 31.
    ↵
    Piga M, Serra A, Deiana L, Brain perfusion abnormalities in patients with euthyroid autoimmune thyroiditis. Eur J Nucl Med Mol Imaging. 2004;31(12):1639-1644. doi:10.1007/s00259-004-1625-7
    Google ScholarCrossRefPubMed
  32. 32.
    ↵
    Zettinig G, Asenbaum S, Fueger BJ, Increased prevalence of sublinical brain perfusion abnormalities in patients with autoimmune thyroiditis: evidence of Hashimoto’s encephalitis?. Clin Endocrinol (Oxf). 2003;59(5):637-643. doi:10.1046/j.1365-2265.2003.01901.x
    Google ScholarCrossRefPubMed
  33. 33.
    ↵
    Leyhe T, Ethofer T, Bretscher J, Low performance in attention testing is associated with reduced grey matter density of the left inferior frontal gyrus in euthyroid patients with Hashimoto’s thyroiditis. Brain Behav Immun. 2013;27(1):33-37. doi:10.1016/j.bbi.2012.09.007
    Google ScholarCrossRefPubMed
  34. 34.
    ↵
    Parle J, Roberts L, Wilson S, A randomized controlled trial of the effect of thyroxine replacement on cognitive function in community-living elderly subjects with subclinical hypothyroidism: the Birmingham Elderly Thyroid study. J Clin Endocrinol Metab. 2010;95(8):3623-3632. doi:10.1210/jc.2009-2571
    Google ScholarCrossRefPubMedWeb of Science
  35. 35.
    ↵
    Jorde R, Waterloo K, Storhaug H, Nyrnes A, Sundsfjord J, Jenssen TG. Neuropsychological function and symptoms in subjects with subclinical hypothyroidism and the effect of thyroxine treatment. J Clin Endocrinol Metab. 2006;91(1):145-153. doi:10.1210/jc.2005-1775
    Google ScholarCrossRefPubMedWeb of Science
  36. 36.
    ↵
    Wekking EM, Appelhof BC, Fliers E, Cognitive functioning and well-being in euthyroid patients on thyroxine replacement therapy for primary hypothyroidism. Eur J Endocrinol. 2005;153(6):747-753. doi:10.1530/eje.1.02025
    Google ScholarCrossRefAbstract/Full TextPubMedWeb of Science
  37. 37.
    ↵
    Ibáñez A, Legaz A, Ruiz-Adame M. Addressing the gaps between socioeconomic disparities and biological models of dementia. Brain. 2023;146(9):3561-3564. doi:10.1093/brain/awad236
    Google ScholarCrossRefPubMed
  38. 38.
    ↵
    Hatzenbuehler ML, McLaughlin KA, Weissman DG, Cikara M. A research agenda for understanding how social inequality is linked to brain structure and function. Nat Hum Behav. 2024;8(1):20-31. doi:10.1038/s41562-023-01774-8
    Google ScholarCrossRefPubMed
  39. 39.
    ↵
    Gonzalez-Gomez R, Legaz A, Moguilner S, Educational disparities in brain health and dementia across Latin America and the United States. Alzheimers Dement. 2024;20(9):5912-5925. doi:10.1002/alz.14085
    Google ScholarCrossRefPubMed
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In this Issue

Clinical Medicine & Research

Clinical Medicine & Research

Vol. 23, Issue 2

1 Aug 2025

Table of Contents Cover (Photo) Index by author

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Keywords

Sustained attention, Neuropsychological symptoms, Subclinical hypothyroidism, CANTAB, Euthyroid, Levothyroxine