Cognition and cerebrovascular function in primary hyperparathyroidism before and after parathyroidectomy

Secular trends in the incidence and treatment patterns of primary hyperparathyroidism in Korea: a nationwide cohort study

Data on epidemiology and secular trend in primary hyperparathyroidism (PHPT) in adults are relatively limited in Asian countries. This study aims to provide an overview of the secular trends in incidence, clinical characteristics, and treatment patterns of PHPT in South Korea. We used Korea's National Health Insurance Claim database (2005-2020) to identify newly diagnosed PHPT cases. Individuals with age below 19, fewer than 2 E21.0 diagnoses, fewer than 2 PTH measurements, secondary hyperparathyroidism, undergoing dialysis or kidney transplantation within a year of diagnosis, parathyroidectomy (PTX) within a year prior to the diagnosis code, and diagnosis of multiple endocrine neoplasm or parathyroid carcinoma were excluded from the analysis. A total of 6837 patients with PHPT (PTX, n = 2989; non-surgery, n = 3848) were compared with 1:10 age- and sex-matched controls (n = 68 370). The mean age of patients with PHPT was 56.0 years, with 77.4% being women. The annual incidence of PHPT increased from 0.23/100 000 persons in 2005 to 1.75 in 2020, with higher rate in women than in men. Compared with 2005-2010 (n = 675), the number of newly diagnosed PHPT cases increased up to 3.1-fold (n = 2119) in 2011-2015 and 6.0-fold (n = 4043) in 2016-2020 periods. Among all patients with PHPT, 43.7% of patients underwent PTX, with decrement of proportion of bilateral surgery among PTX group across time (11.9% in 2005-2010 to 8.9% in 2016-2020, P for trend .033). Among all patients with PHPT, non-surgery group increased from 41.6% in 2005-2010 to 58.0% in 2016-2020 (P for trend <.001). Patients with PHPT had higher odds of osteoporosis (odds ratio [OR] 7.03), renal stones (OR 10.55), chronic kidney diseases (OR 7.42), and cardiovascular, metabolic, and neurological conditions after adjustment for comorbidity index. In summary, the incidence of PHPT increased from 2005 to 2020 with predominance of non-surgical treatment, which calls for research focus on improving non-surgical management.

Interactions between PTH and adiposity: appetizing possibilities

Although parathyroid hormone (PTH) is best known for its role as a regulator of skeletal remodelling and calcium homeostasis, more recent evidence supports a role for it in energy metabolism and other non-classical targets. In this report, we summarize evidence for an effect of PTH on adipocytes. This review is based upon all peer-reviewed papers, published in the English language with PubMed as the primary search engine. Recent preclinical studies have documented an effect of PTH to stimulate lipolysis in both adipocytes and liver cells and to cause browning of adipocytes. PTH also reduces bone marrow adiposity and hepatic steatosis. Although clinical studies are limited, disease models of PTH excess and PTH deficiency lend support to these preclinical findings. This review supports the concept of PTH as a polyfunctional hormone that influences energy metabolism as well as bone metabolism.

Machine learning-based prediction models for parathyroid carcinoma using pre-surgery cognitive function and clinical features

Patients with parathyroid carcinoma (PC) are often diagnosed postoperatively, due to incomplete resection during the initial surgery, resulting in poor outcomes. The aim of our study was to investigate the pre-surgery indicators of PC and try to develop a predictive model for PC utilizing machine learning. Evaluation of pre-surgery neuropsychological function and confirmation of pathology were carried out in 133 patients with primary hyperparathyroidism in Beijing Chaoyang Hospital from December 2019 to January 2023. Patients were randomly divided into a training cohort (n = 93) and a validating cohort (n = 40). Analysis of the clinical dataset, two machine learning including the extreme gradient boosting (XGBoost) and the least absolute shrinkage and selection operator (LASSO) regression were utilized to develop the prediction model for PC. Logistic regression analysis was also conducted for comparison. Significant differences in elevated parathyroid hormone and decreased serum phosphorus in PC compared to (BP). The lower score of MMSE and MOCA was observed in PC and a cutoff of MMSE < 24 was the optimal threshold to stratify PC from BP (area under the curve AUC 0.699 vs 0.625). The predicted probability of PC by machine learning was similar to the observed probability in the test set, whereas the logistic model tended to overpredict the possibility of PC. The XGBoost model attained a higher AUC than the logistic algorithms and LASSO models. (0.835 vs 0.683 vs 0.607). Preoperative cognitive function may be a probable predictor for PC. The cognitive function-based prediction model based on the XGBoost algorithm outperformed LASSO and logistic regression, providing valuable preoperative assistance to surgeons in clinical decision-making for patients suspected PC.

Effects of successful parathyroidectomy on neuropsychological and cognitive status in patients with asymptomatic primary hyperparathyroidism

PURPOSE

Besides typical clinical symptoms, primary hyperparathyroidism (pHPT) is associated with impaired quality of life and cognitive status. The aim of this study was to evaluate the quality of life and cognitive impairment in patients with pHPT, before and after parathyroidectomy.

METHODS

We conducted a panel study, which included asymptomatic pHPT patients scheduled for parathyroidectomy. Besides demographic and clinical data, patients' quality of life and cognitive capacity were recorded before, 1 month, and 6 months following parathyroidectomy using the Short Form 36 questionnaire (RAND-36), Beck Depression Inventory (BDI), Depression Anxiety Stress Scales (DASS), Mini-Mental State Examination (MMSE), and Symptom Check List 90-revised version (SCL90R).

RESULTS

During a 2-year follow-up, 101 patients entered the study (88 women), with an average age of 60.7 years. The Global score of RAND-36 test ameliorated by almost 50% 6 months after parathyroidectomy. The most sustained subscores of the RAND-36 test were role functioning/physical and health change, with an improvement of more than 125%. According to the BDI, DASS depression subscore, and SCL90R depression subscore, the extent of depressive symptoms reduction was approximately 60% 6 months postoperatively. The level of anxiety was reduced by 62.4%, measured by both the DASS and SCL90R anxiety subscores. The stress level was almost halved according to the DASS stress subscore (from 10.7 to 5.6 points). The results of the MMSE test showed a significant improvement postoperatively, for 1.2 points (4.4%). A worse preoperative score of each tool was related to the higher magnitude of improvement 6 months after parathyroidectomy.

CONCLUSION

A considerable number of pHPT patients, even without other typical symptoms, show signs of impaired quality of life and neurocognitive status preoperatively. After a successful parathyroidectomy, there is an improvement in quality of life, declined levels of depression, anxiety, and stress, as well as amelioration of cognitive status. Patients with more impaired quality of life and pronounced neurocognitive symptoms may expect more benefits from the surgery.

Secondary Hyperparathyroidism and Cognitive Decline

Purpose of Review

Secondary hyperparathyroidism (SHPT) likely contributes to the high prevalence of cognitive decline found among individuals with end-stage kidney disease (ESKD). Our objective is to critically evaluate the recent literature regarding the association between SHPT and cognitive decline and identify potential mechanisms.

Recent Findings

Nine studies assessing the relationship between SHPT and cognition have been published in the last two decades, each showing that elevated parathyroid hormone (PTH) levels were associated with cognitive decline. One also found structural changes within the brain related to SHPT. Additionally, two found that SHPT treatment decreases the risk of cognitive decline in ESKD patients.

Summary

SHPT is associated with cognitive impairment. However, the severity of SHPT associated with these changes and the specific cognitive domains affected remain unclear. Future studies are needed to focus on specific cognitive domains, the trajectory of cognitive decline, and optimal treatment strategies including the impact of kidney transplant and tertiary hyperparathyroidism.

Parathyroid Hormone (PTH)-Related Peptides Family: An Intriguing Role in the Central Nervous System

Parathyroid Hormone (PTH) plays a crucial role in the maintenance of calcium homeostasis directly acting on bone and kidneys and indirectly on the intestine. However, a large family of PTH-related peptides exists that exerts other physiological effects on different tissues and organs, such as the Central Nervous System (CNS). In humans, PTH-related peptides are Parathyroid Hormone (PTH), PTH-like hormones (PTHrP and PTHLH), and tuberoinfundibular peptide of 39 (TIP39 or PTH2). With different affinities, these ligands can bind parathyroid receptor type 1 (PTH1R) and type 2 (PTH2R), which are part of the type II G-protein-coupled-receptors (GPCRs) family. The PTH/PTHrP/PTH1R system has been found to be expressed in many areas of the brain (hippocampus, amygdala, hypothalamus, caudate nucleus, corpus callosum, subthalamic nucleus, thalamus, substantia nigra, cerebellum), and literature data suggest the system exercises a protective action against neuroinflammation and neurodegeneration, with positive effects on memory and hyperalgesia. TIP39 is a small peptide belonging to the PTH-related family with a high affinity for PTH2R in the CNS. The TIP39/PTH2R system has been proposed to mediate many regulatory and functional roles in the brain and to modulate auditory, nociceptive, and sexual maturation functions. This review aims to summarize the knowledge of PTH-related peptides distribution and functions in the CNS and to highlight the gaps that still need to be filled.

Quality of Life in Primary Hyperparathyroidism

Quality of life is impaired in primary hyperparathyroidism (PHPT), regardless of the severity of the disease. Clinical studies have employed different instruments, including standardized and disease-specific questionnaires, and including patients with different phenotypes of PHPT. Neuropsychiatric symptoms and decline in cognitive status are common in PHPT. Patients may complain of these issues or they can be ascertained by questionnaires; they include depression, anxiety, impaired vitality, social and emotional functions, sleep disturbances, and altered mental function. Randomized controlled trials on the effects of surgical versus non-surgical treatments have collectively shown improvement in quality of life after parathyroidectomy, but results have been heterogeneous.

Classical and Nonclassical Manifestations of Primary Hyperparathyroidism

This narrative review summarizes data on classical and nonclassical manifestations of primary hyperparathyroidism (PHPT). It is based on a rigorous literature search, inclusive of a Medline search for systematic reviews from 1940 to December 2020, coupled with a targeted search for original publications, covering four databases, from January 2013-December 2020, and relevant articles from authors' libraries. We present the most recent information, identify knowledge gaps, and suggest a research agenda. The shift in the presentation of PHPT from a predominantly symptomatic to an asymptomatic disease, with its varied manifestations, has presented several challenges. Subclinical nephrolithiasis and vertebral fractures are common in patients with asymptomatic disease. The natural history of asymptomatic PHPT with no end organ damage at diagnosis is unclear. Some observational and cross-sectional studies continue to show associations between PHPT and cardiovascular and neuropsychological abnormalities, among the different disease phenotypes. Their causal relationship is uncertain. Limited new data are available on the natural history of skeletal, renal, cardiovascular, neuropsychological, and neuromuscular manifestations and quality of life. Normocalcemic PHPT (NPHPT) is often diagnosed without the fulfillment of rigorous criteria. Randomized clinical trials have not demonstrated a consistent long-term benefit of parathyroidectomy (PTX) versus observation on nonclassical manifestations. We propose further refining the definition of asymptomatic disease, into two phenotypes: one without and one with evidence of target organ involvement, upon the standard evaluation detailed in our recommendations. Each of these phenotypes can present with or without non-classical manifestations. We propose multiple albumin-adjusted serum calcium determinations (albumin-adjusted and ionized) and exclusion of all secondary causes of high parathyroid hormone (PTH) when establishing the diagnosis of NPHPT. Refining the definition of asymptomatic disease into the phenotypes proposed will afford insights into their natural history and response to interventions. This would also pave the way for the development of evidence-based guidance and recommendations. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Cognitive deficits in primary hyperparathyroidism - what we know and what we do not know: A narrative review

Classic symptoms of primary hyperparathyroidism (PHPT) are seen in approximately 20% of patients. While features such as kidney stones and skeletal disease are often highlighted as directly related to the disease, others can be even more prevalent. For example, cognitive dysfunction and reduced quality of life are common complaints in many patients, even among those who are classified as being asymptomatic. The pathophysiology of PHPT involves the impact of excess parathyroid hormone (PTH) on calcium metabolism. Referencing putative neurocognitive issues, many animal studies have illustrated the potential roles of PTH and PTH receptors in the brain. Functional imaging and pre-and post-parathyroidectomy studies have suggested a link between the neuronal impact of elevated PTH levels on specific functional aspects of the central nervous system, such as cognition. Confounding a direct role for PTH are hypercalcemia and vitamin D deficiency, both of which could conceivably alter CNS function in PHPT. The lack of strong evidence that parathyroidectomy improves cognition in patients with PHPT raises the question as to whether parathyroid surgery should be recommended on this basis alone. This narrative review summarizes the available literature on neurocognitive function in PHPT.

The impact of age on quality of life and frailty outcomes after parathyroidectomy in patients with primary hyperparathyroidism

OBJECTIVE

Parathyroidectomy (PTx) improves quality of life (QoL) in patients with primary hyperparathyroidism (PHPT). Whether this effect is modified according to the patients' age is unknown. The aim of this study was to evaluate the impact of age on the effect of PTx on QoL and frailty in patients with PHPT, six months post-PTx.

METHODS

This was a prospective cohort study, including patients with PHPT, admitted from January 2016 to December 2019, divided into two categories: younger (≤ 65 years old) and older (> 65 years old). QoL was assessed with the Pasieka questionnaire (PAS-Q) two days pre- and six months post-operatively. Frailty was also assessed at the same time intervals, with the Frailty Index (FI).

RESULTS

One hundred and thirty-four patients (younger group: 96 patients, mean age 50.4 ± 9.8 years; older group: 38 patients, mean age 72.1 ± 4.9 years) were included. PTx resulted in a significant reduction in PAS-Q score in both groups. Notably, a greater reduction in "mood swings", "irritability", "itchy skin" and "feeling thirsty" PAS-Q domains was observed in the younger group. In contrast, a greater decrease in "bone pain", "tiredness", "weakness", "joint pain", "getting off chair" and "headaches" items was observed in the older group. Moreover, PTx led to a decrease in FI only in this group.

CONCLUSIONS

PTx leads to an improvement in QoL both in older (> 65 years) and younger (≤ 65 years) patients with PHPT, attributed to a differential effect on PAS-Q items. Frailty improves only in the older group.

Successful parathyroidectomy improves cognition in patients with primary hyperparathyroidism: A prospective study in a tertiary medical center and comprehensive review of the literature

CONTEXT

The recent American and European guidelines on management of patients with primary hyperparathyroidism (PHPT) did not endorse neurocognitive evaluation as part of standard work-up and did not consider it as a surgery criterion.The neurocognitive deleterious effects of hyperparathyroidism and impact of parathyroidectomy on PHPT patients is yet to be elucidated.

OBJECTIVE

To evaluate specific neurocognitive functions in PHPT patients prior to parathyroidectomy and describe the changes during follow-up with serial evaluations.

DESIGN

A prospective case-control study including parathyroidectomy candidates evaluated at a tertiary teaching university hospital. Thorough neurocognitive evaluation was conducted before and 1- & 6-months following parathyroidectomy: Rey Auditory Verbal Learning Test (RAVLT), Rey-Osterrieth Complex Figure Test (ROCF), Trail Making Test A, Trail Making Test B, Addenbrooke's Cognitive Examination-III (ACE), Frontal Assessment Battery (FAB), Beck Depression Inventory (BDI).

RESULTS

18 consecutive patients underwent successful parathyroidectomy. Various neurocognitive functions improved significantly after successful parathyroidectomy: long term auditory memory (RAVLT, p=0.008), short- and long-term visual memory (ROCF, p=0.006 and p=0.002 respectively), visual attention and complex concentration skills (trail making A, p<0.001) and executive abilities (trail making B, p=0.005). No change was identified in frontal-lobe abilities. Depression symptoms were absent or minimal prior to surgery and no significant change was observed after surgery.

CONCLUSIONS

PHPT is associated with significant various neurocognitive dysfunctions when mindfully evaluated before surgery. Successful parathyroidectomy results in several neurocognitive aspect improvements. The data suggest that neurocognitive deterioration may be considered an added parathyroidectomy criterion when surgical decision is not straightforward.

Nontraditional Aspects of Sporadic Primary Hyperparathyroidism

Nontraditional aspects of primary hyperparathyroidism refer to the condition's rheumatic, gastrointestinal, cardiovascular, and neuropsychological effects. Although gastrointestinal and rheumatic symptomatology were features of classical primary hyperparathyroidism, they do not seem to be a part of the modern presentation of primary hyperparathyroidism. In contrast, neuropsychological symptoms such as altered mood and cognition, as well as cardiovascular disease, have been associated with the form of primary hyperparathyroidism seen today, but the relationship is not clearly causal. Evidence does not support reversibility after parathyroidectomy and therefore none of the nontraditional manifestations are considered sole indications for recommending surgery at this time.

Effects of Parathyroidectomy on Normocalcemic Primary Hyperparathyroidism and the Role of Intraoperative PTH Measurement

BACKGROUND

Normocalcemic primary hyperparathyroidism (NCpHPT) and normohormonal primary hyperparathyroidism (NHpHPT) are recently recognized variants of primary hyperparathyroidism. Current guidelines for the management hyperparathyroidism recognize NCpHPT as one of the areas that are recommended for more research due to limited available data.

METHODS

A retrospective review of patients who had parathyroidectomy between 2014 and 2019. We excluded patients with multiple endocrine neoplasia syndromes and secondary and tertiary hyperparathyroidism. Included patients were classified based on the biochemical profile into classic or normocalcemic hyperparathyroidism group. Collected data included demographics, preoperative localizing imaging, intraoperative parathyroid hormone levels, and postoperative cure rates.

RESULTS

261 patients were included: 160 patients in the classic and 101 patients in the normocalcemic group. Patients in the normocalcemic group had significantly more negative sestamibi scans (n = 58 [8.2%] vs 78 [51.3%], P = <.01), smaller parathyroid glands (mean weight 436.0 ± 593.0 vs 742.4 ± 1109.0 mg, P = .02), higher parathyroid hyperplasia rates (n = 51 [50.5%] vs 69 [43.1%]), and significantly higher intraoperative parathyroid hormone at 10 minutes (78.1 ± 194.6 vs 43.9 ± 62.4 1, P = .04). Positive predictive value of both intraoperative parathyroid hormone and cure rate was lower in the normocalcemic group (84.2% vs 95.7%) and (80.5% vs 95%), respectively.

CONCLUSION

Normocalcemic hyperparathyroidism is a challenging disease. Surgeons should be aware of the lower cure rate in this group, interpret intraoperative parathyroid hormone with caution, and have a lower threshold for bilateral neck exploration and 4 glands visualization.

Parathyroidectomy slows renal function decline in patients with primary hyperparathyroidism

PURPOSE

Primary hyperparathyroidism has deleterious effects on health and causes nephrolithiasis and osteoporosis. However, it remains unclear whether parathyroidectomy benefits kidney function among patients with primary hyperparathyroidism.

METHODS

In this retrospective study, patients with primary hyperparathyroidism receiving parathyroidectomy in a tertiary medical center between 2003 and 2017 were followed up until December 31 2017, death, or requiring renal replacement therapy. Impact of parathyroidectomy on kidney function was examined using longitudinal estimated glomerular filtration rate (eGFR) change scales: single, average, absolute difference, percent change, annual decline rate, and slope. We applied linear mixed-effect model to determine the effect of parathyroidectomy on kidney function.

RESULTS

During study period, 167 patients with primary hyperparathyroidism were identified from 498 parathyroidectomized patients, and finally, 27 patients fulfilled our stringent criteria. Median follow-up duration was 1.50 years (interquartile range 1.05-1.81) before surgery and 2.47 years (1.37-6.43) after surgery. Although parathyroidectomy did not affect amount of proteinuria and distribution of eGFR, parathyroidectomy significantly slowed decline rate of eGFR compared with that before surgery (- 1.67 versus - 2.73 mL/min/1.73 m²/year, p < 0.001). More importantly, parathyroidectomy made more beneficial effects on kidney function in patients with age < 65 years and those without chronic kidney disease or hypertension.

CONCLUSIONS

Our study showed that parathyroidectomy slows renal function decline irrespective of age or comorbidities, which offers novel insight into the revision of guidelines for surgical indications in primary hyperparathyroidism. Given small sample size, further large-scale controlled studies are warranted to confirm our findings.

The Associations of Serum Osteocalcin and Cortisol Levels With the Psychological Performance in Primary Hyperparathyroidism Patients

OBJECTIVES

The aim of this study was to investigate factors responsible for the psychological performance in primary hyperparathyroidism (PHPT) patients.

METHODS

A group of 38 PHPT patients receiving questionnaires, including Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), and 36-Item Short Form Survey (SF-36), was evaluated. The relationships between scores of questionnaires and clinical biomarkers were examined. Collinearity and linear regression model were applied to examine variables determining the scores of the questionnaire. In 192 PHPT patients, bivariate and partial correlation were used to analyze the relationships between serum concentrations of parathyroid hormone (PTH), calcium, osteocalcin (OCN), and cortisol.

RESULTS

Among 38 patients receiving questionnaire tests, 50% (19/38) of the patients developed state anxiety, 60.5% (23/38) of the patients had the trait of developing anxiety. In addition, 18.4% (7/38) of the patients developed mild to severe depression. Serum cortisol at 8:00 was negatively and significantly correlated with social function (r = -0.389, p = 0.041) after controlling for age, sex, disease duration, serum PTH, calcium, phosphorus, and 25-hydroxyvitamin D [25(OH)D] concentration. OCN was significantly and negatively correlated with score of STAI-S (r = -0.426, p = 0.027). In the linear regression model for BDI score, variables with statistical significance were serum OCN (β = -0.422, p = 0.019) and cortisol at 0:00 (β = 0.371, p = 0.037). In 192 PHPT patients, the serum concentration of OCN (r = 0.373, p = 0.000) was positively correlated with PTH level. After controlling for age, sex, disease duration, serum 25(OH)D, phosphorus, and calcium concentration, the positive correlation between OCN and PTH was still statistically significant (r = 0.323, p = 0.000). The serum concentration of cortisol at 0:00 was significantly and positively correlated with serum calcium (r = 0.246, p = 0.001) in bivariate correlation analysis. After controlling for age, sex, disease duration, serum PTH, 25(OH)D, and phosphorus concentration, serum cortisol at 0:00 was still positively and significantly correlated with serum calcium (r = 0.245, p = 0.001).

CONCLUSION

Serum levels of OCN and cortisol, rather than PTH and calcium, are associated with the development of anxiety and depression symptoms in PHPT patients.

Normocalcemic Hyperparathyroidism: A Heterogeneous Disorder Often Misdiagnosed?

Normocalcemic primary hyperparathyroidism (NHPT) was first described over 10 years ago, but uncertainties still remain about its definition, prevalence, and rates of complications. As a result, consensus management guidelines for this condition have not yet been published. Several hypotheses have been proposed for the pathophysiology of NHPT, but it may be a heterogeneous disorder with multiple causes, rather than a single etiology that explains this biochemical phenotype. A common clinical concern is whether NHPT should be treated surgically when complications are already present at first recognition of the disorder, rather than following patients clinically over time. The literature on NHPT is based mostly on larger studies of population‐based cohorts and smaller studies from referral centers. Lack of rigorous diagnostic criteria and selection bias inherent in populations seen at tertiary referral centers may explain the heterogeneity of reported rates of bone and renal complications in relation to consistently mild laboratory alterations. Unresolved questions remain about the significance of NHPT when it is diagnosed biochemically without evident bone or kidney complications. Moreover, its natural history remains to be elucidated because a proportion of what is classified as NHPT may revert to normal spontaneously, thus revealing previously unrecognized secondary hyperparathyroidism. These issues indicate that caution should be used in recommending surgery for NHPT. This review will focus on recent issues regarding the pathophysiology, evaluation, and management of NHPT. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Functional magnetic resonance imaging in primary hyperparathyroidism

OBJECTIVE

The neurophysiological mechanisms underlying cognitive dysfunction in primary hyperparathyroidism (PHPT) and the brain regions affected are not clear. We assessed neural activation during cognitive testing (matrix reasoning, paired associates, and logical memory) using functional MRI (fMRI) in 23 patients with PHPT and 23 healthy controls. A subset with PHPT was re-assessed 6 months post-parathyroidectomy (PTX).

DESIGN

This is an observational study comparing neural activation by fMRI in patients with PHPT to normative controls. Postmenopausal women were studied at a tertiary referral center.

RESULTS

There were no between-group differences in cognitive task performance. Patients with PHPT had lower neural activation vs controls (max Z = 4.02, all P < 0.01) during matrix reasoning in brain regions involved in executive function (left frontal lobe (k = 57) and right medial frontal gyrus (k = 72)) and motor function (right precentral gyrus (k = 51)). During paired associates (verbal memory), those with PHPT had greater activation in the right inferior parietal lobule (language/mathematical operations; k = 65, P < 0.01). Greater activation in this region bilaterally correlated with higher PTH (k = 96, P < 0.01). Post-PTX, activation decreased during matrix reasoning, but in different regions than those affected pre-PTX.

CONCLUSIONS

PHPT is associated with differences in task-related neural activation patterns, but no difference in cognitive performance. While this may indicate compensation to maintain the same cognitive function, there was no clear improvement in neural activation after PTX. Larger, longitudinal studies that include PHPT patients followed without surgery are needed to determine if PTX could prevent worsening of altered neural activation patterns in PHPT.