Decision-Making in Patients with Hyperthyroidism: A Neuropsychological Study

Hyperthyroidism leads learning and memory impairment possibly via GRIN2B expression alterations

The hippocampus as an important structure for learning and memory functions contains a high level of thyroid hormone receptors. Although there are numerous studies investigating the effects of thyroid hormones on cognitive dysfunction and psychiatric symptoms, the underlying molecular processes of these disorders have not yet been fully elucidated. In the present study, 24 male adult rats (4 months) were divided into 3 groups: control group, sham group and hyperthyroid group. Hyperthyroid group and sham group were treated with l-thyroxine or saline for 21 days. Each group was exposed to Morris water maze testing (MWMT), measuring their performance in a hidden-platform spatial task. After learning and memory tests, intracardiac blood was taken from the rats for serum thyroxine levels. Following blood collection, the rats were decapitated to isolate hippocampal tissue. GRIN2A, GRIN2B, BDNF, cFOS, Cdk5, cdk5r1 (p35), and cdk5r2 (p39) gene expression were evaluated using quantitative reverse transcriptase-PCR. Serum thyroxine level was found to be higher in hyperthyroid rats than in the control and sham groups. According to our MWMT findings, the memory performance of the hyperthyroid group was significantly impaired compared to the control and sham groups (p < 0.05). In the hippocampus, the GRIN2A gene expression level was decreased in the sham group, and the GRIN2B gene expression level was decreased in the sham and hyperthyroid groups compared to the control group (p < 0.05). There was no significant difference in other genes (p > 0.05). Hyperthyroidism impaired hippocampus-dependent spatial memory. Hyperthyroidism caused decreased level of GRIN2B gene expression in the hippocampus.

Resting Electroencephalography Differences Between Eyes-Closed and Eyes-Open Conditions in Children with Subclinical Hypothyroidism

OBJECTIVE

Electroencephalography changes that occur during the transition from eyes-closed to the eyes-open state in resting condition are related to the early phase of sensory processing and are defined as activation. The present study aimed to reveal the potential deteriorations that may occur in the initial period of sensory processing in resting electroencephalography between children with subclinical hypothyroidism and a control group.

MATERIALS AND METHODS

Electroencephalographies of 15 children with subclinical hypothyroidism and 15 healthy children aged 10 to 17 years were recorded for 2 minutes for EC and 2 minutes for eyes-open conditions in resting state. Absolute electroencephalography band powers (μV2 ) within the delta, theta, alpha, and beta frequency bands were calculated in Fz, Cz, Pz, and Oz electrodes, respectively, for eyes-closed and eyes-open conditions.

RESULTS

The results show that, although there was no noteworthy difference between the powers of the electroencephalography frequency bands of children with subclinical hypothyroidism and healthy children during the eyes-open condition, the alpha powers of the control group were significantly higher in all electrodes during the eyes-closed condition. Furthermore, the powers of all frequency bands were observed to decrease in the eyes-open condition in the control group. However, the same net decrease was not observed in the frequency powers of children with subclinical hypothyroidism.

CONCLUSION

According to the results of this study, children with subclinical hypothyroidism may experience information processing impairments starting in the early stages of sensory processing.

Selective Attention and Information Processing Speed in Graves' Disease: Stroop Interference Effect

Background

Cognitive functions are affected by thyroid hormones. In this study, we aimed to investigate the selective attention and information processing speed in thyrotoxic Graves’ disease.

Methodology

This study was conducted among 40 patients with thyrotoxic Graves’ disease and age and gender-matched 40 healthy controls. Stroop Color and Word test were applied to healthy controls once and to patients with Graves’ disease during thyrotoxic and euthyroid periods. Stroop interference effect was calculated.

Results

The mean age was 34.67 ± 11 in the Graves’ group and 34.72 ± 9.16 in the control group (p > 0.05). The number of errors and self-corrections in Stroop Color and Word test was higher in patients with thyrotoxic Graves’ disease than both patients with euthyroid Graves’ disease and healthy controls (p < 0.05). Stroop interference effect was significantly longer in patients with thyrotoxic Graves’ disease than both patients with euthyroid Graves’ disease and healthy controls (p < 0.05). All parameters obtained from the Stroop Color and Word test including errors, self-corrections, and Stroop interference effect were similar in patients with euthyroid Graves’ disease and healthy controls.

Conclusions

Selective attention was impaired and information processing speed was slow in patients with thyrotoxic Graves’ disease, and these findings were associated with age and educational level. After becoming euthyroid through antithyroid medication, these pathological findings returned to normal levels. Additionally, Stroop interference effect was significantly decreased when patients with Graves’ disease became euthyroid.

Risk Preferences, Rationality of Choices, and Willingness to Pay for Preventive Medicine in Patients with Graves' Thyrotoxicosis

PURPOSE

Patients with thyrotoxicosis show neuropsychological changes, and these may damage the quality of informed consent in clinical practice. Therefore, we examined patients' real-life preferences to assess whether change in risk preferences was dependent on thyroid function state.

PATIENTS AND METHODS

The participants were 86 patients who were newly diagnosed with Graves' thyrotoxicosis between 1 January and 31 December 2018 (group A), and an additional 33 euthyroid patients diagnosed before 2018 (group B). In a survey conducted via a questionnaire based on the concept of behavioral economics, we sought to determine risk preferences, rationality of choices, and other relevant factors. An identical second survey was completed 6-12 months later by 36 patients in group A after their thyroid functions had been normalized by treatment, and by 11 euthyroid patients in group B. We performed paired analysis of the first and second surveys in 32 patients of group A and single regression analysis of a total of 140 surveys obtained from 119 patients by combining the first and second surveys of groups A and B with serum level of FT3 as an independent variable.

RESULTS

The paired analysis indicated that there was no significant difference in any survey item. The single regression analysis revealed that willingness-to-pay (WTP) for preventive medicine and monthly average out-of-pocket (OOP) expenditure on medical care were both significantly positively associated with serum level of FT3. Patients in the hyperthyroid state tend to have high WTP for preventive medicine, which may be accelerated by the anchoring effect of OOP expenditure.

CONCLUSION

Almost all risk preferences of patients with Graves' disease are constant, rational, and reproducible in the hyperthyroid and euthyroid states. However, medical professionals should be aware that the willingness of patients with thyrotoxicosis to pay for medical costs may change after the normalization of thyroid function.

Reversible Affective Symptoms and Attention Executive Control Network Impairment Following Thyroid Function Normalization in Hyperthyroidism

INTRODUCTION

Affective symptoms and attention impairments are found in patients with hyperthyroidism. Our previous data have revealed that the patients with hyperthyroidism experience impairments of the attention networks, but it remains unclear whether these disorders persist after the treatment of hyperthyroidism.

METHODS

Twenty healthy controls and 25 hyperthyroid patients were recruited and performed the attention network test (ANT) which can simultaneously examine the alertness, orientation and execution control components of the participants. The effect of treatment on affective symptom and attention networks impairments were examined in the patient group after 1-year anti-thyroid medication and reaching euthyroidism for at least 3 months.

RESULTS

Anxiety and depression scores of patients with hyperthyroidism were significantly higher than those of the healthy control group. The patients with hyperthyroidism had impairments of the alerting and executive control networks. Meanwhile, the score of HAMA correlated significantly with thyroid hormone and TSH levels, and there was a negative significant correlation between the score of HAMD and TSH level in all subjects. There was a positive correlation between the value of the executive control network and thyroid hormones' levels in all subjects and in the hyperthyroidism group. Anxiety and depression symptoms were improved with methimazole treatment after euthyroidism was reached. The value of the executive control network no longer differed from that of healthy controls, but deficits in the alerting network of hyperthyroidism still persisted after treatment.

CONCLUSION

The patients with hyperthyroidism existed affective symptoms and attention networks impairments. Affective symptoms and attention executive control network impairment were improved following thyroid function normalization in hyperthyroidism.

Assigning Clinical Significance and Symptom Severity Using the Zung Scales: Levels of Misclassification Arising from Confusion between Index and Raw Scores

BACKGROUND

The Zung Self-Rating Depression Scale (SDS) and Self-Rating Anxiety Scale (SAS) are two norm-referenced scales commonly used to identify the presence of depression and anxiety in clinical research. Unfortunately, several researchers have mistakenly applied index score criteria to raw scores when assigning clinical significance and symptom severity ratings. This study examined the extent of this problem.

METHOD

102 papers published over the six-year period from 2010 to 2015 were used to establish two convenience samples of 60 usages of each Zung scale.

RESULTS

In those papers where cut-off scores were used (i.e., 45/60 for SDS and 40/60 for SAS), up to 51% of SDS and 45% of SAS papers involved the incorrect application of index score criteria to raw scores. Inconsistencies were also noted in the severity ranges and cut-off scores used.

CONCLUSIONS

A large percentage of publications involving the Zung SDS and SAS scales are using incorrect criteria for the classification of clinically significant symptoms of depression and anxiety. The most common error-applying index score criteria to raw scores-produces a substantial elevation of the cut-off points for significance. Given the continuing usage of these scales, it is important that these inconsistencies be highlighted and resolved.

Impaired decision making under risky conditions in the acute phase of Graves' thyroitoxicosis

The patients with Graves' thyroitoxicosis often complain that they have neuropsychiatric symptoms and impaired cognitive function. Decision making is important and complex process involving the interaction and integration of a series of cognitive components. In the 31 newly diagnosed patients with Graves' thyroitoxicosis and 30 healthy controls, we used the Hamilton Anxiety Rating Scale (HAMD), Hamilton Depression Rating Scale (HAMD) and The Game of Dice Task (GDT) to assess the emotion and decision making under risky conditions. The patients with Graves' disease had higher score on HAMA and HAMD, and had poorer performance in GDT than healthy controls. A negative correlation was found between utilization of negative feedback and score of HAMA in the patients with Graves' disease. Our findings in Graves' disease might be association with the extensive brain disorders including prefrontal cortex and the limbic system, and dopamine dysfunction.

Changes in Resting-State Cerebral Activity in Patients with Hyperthyroidism: A Short-Term Follow-Up Functional MR Imaging Study

To investigate the brain functional abnormality of hyperthyroid patients before and after treatment for one month using resting-state functional magnetic resonance imaging (rs-fMRI). Amplitude of low-frequency fluctuation (ALFF) and seed-based functional connectivity (FC) analysis were performed in 27 new-onset untreated hyperthyroid patients relative to 30 healthy controls. In addition, follow-up data were available for 19 patients treated with methimazole for one month. Compared with healthy controls, patients exhibited lower ALFF in the right posterior cingulate cortex (PCC); increased FC in the bilateral anterior insula (AI), bilateral posterior insula (PI) and left anterior lobe of the cerebellum (ALC); and decreased FC in the bilateral lateral prefrontal cortex (LPFC), the right medial temporal gyrus (MTG) and the bilateral PCC. Compared with the hyperthyroid status, patients with improved thyroid function showed increased FC in the right LPFC and right dorsolateral prefrontal cortex (DLPFC). Subsequently, Pearson’s correlation analyses were performed between abnormal ALFF, FC, neuropsychological assessment and serum free triiodothyronine (FT3) levels. The results indicated that the alterations in regional and network-level brain functions, which might underlie different psychiatric complications were dynamic and interactional processes in hyperthyroidism. Moreover, the improvement in regional brain FC was correlated with the efficacy of anti-thyroid medication.