Cognitive decline with hypoparathyroidism linked to changes in brain structure
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Key takeaways:
- Adults with hypoparathyroidism had worse processing speed and visual and auditory memory than healthy controls.
- Most subcortical brain structures were smaller among the hypoparathyroidism group.
Adults with hypoparathyroidism experience declines in cognitive function that may be due to structural changes in the brain, according to findings published in the Journal of Bone and Mineral Research.
“In this exploratory study, we have shown that there is a difference in brain structure between patients with hypoparathyroidism and healthy controls,” Tanja Sikjaer, MD, PhD, of the departments of endocrinology and internal medicine at Aarhus University Hospital in Denmark, and colleagues wrote. “We have found a smaller hippocampus in patients with postsurgical hypoparathyroidism or nonsurgical hypoparathyroidism and a correlation between disease duration and a smaller bilateral thalamus in patients with postsurgical hypoparathyroidism.”
Researchers conducted a cross-sectional study recruiting 36 adults aged 18 to 80 years with hypoparathyroidism who received care at the endocrinology outpatient clinic of Aarhus University Hospital. The hypoparathyroidism group included 26 adults with postsurgical hypoparathyroidism and 10 with nonsurgical hypoparathyroidism. Those with postsurgical hypoparathyroidism were matched by age, sex and education level with a control group of adults without hypoparathyroidism who were recruited from the Danish National Population Register. Participants completed the SF-36 version 2 to self-report quality of life, the WHO-5 Well-Being Index, the 28-item Hypoparathyroid Patient Questionnaire to assess cognitive function and symptoms related to hypoparathyroidism, and the Hypoparathyroidism Symptom Diary to determine the degree of hypoparathyroidism symptoms and their impact. All participants underwent MRI scans and neuropsychological testing to assess cognitive performance. Blood samples were collected on the day of the MRI.
Depression, cognitive decline reported
On the WHO-5 Well-Being Index, 23% of the postsurgical hypoparathyroidism group and 40% of those with nonsurgical hypoparathyroidism had a score of less than 28, indicating symptoms of depression. No control group participants had a score of less than 28. Adults with postsurgical hypoparathyroidism had worse scores on both the physical and mental components of the SF-36 and the nonsurgical hypoparathyroidism group had worse scores on seven subdomains of the questionnaire compared with controls.
Adults with postsurgical hypoparathyroidism reported more neurovegetative symptoms, loss of vitality, pain and cramps, depression and anxiety, heart palpitations and numbness and tingling than the control group. Those with nonsurgical hypothyroidism had more loss of vitality, pain and cramps and numbness and tingling than controls. On the Hypoparathyroidism Symptom Diary, adults with postsurgical hypoparathyroidism reported a higher degree of symptoms than the control group, and participants with nonsurgical hypoparathyroidism reported more muscle spasms and tiredness than controls. The most troublesome symptom for both hypoparathyroidism groups was physical fatigue, reported by 54% of those with postsurgical hypoparathyroidism and 40% of people with nonsurgical hypoparathyroidism.
Both hypoparathyroidism groups had worse processing speed, visual memory and auditory memory on cognitive performance assessments than controls. Longer disease duration was associated with worse visual memory for adults with postsurgical hypoparathyroidism. Adults with nonsurgical hypoparathyroidism also had a lower performance for executive functions than the control group.
Brain changes with hypoparathyroidism
With the exception of the caudate nucleus for postsurgical hypoparathyroidism adults and the putamen for those with nonsurgical hypoparathyroidism, all subcortical brain structures were smaller for hypoparathyroidism participants than controls. Adults who reported severe brain fog with hypoparathyroidism had smaller hippocampi than those reporting mild or moderate brain fog.
“Interestingly, the hippocampus was the only structure that could be associated with self-reported brain fog when dichotomizing the hypoparathyroidism groups into mild and severe brain fog,” the researchers wrote. “This indicates that the cognitive impairment experienced may be related to changes in brain structure even though neither brain fog nor hippocampal volume could be associated with performances on cognitive tests.”
When both hypoparathyroidism groups were combined, thalamus volume was bilaterally correlated with auditory memory, whereas caudate volume was bilaterally correlated with executive function and computerized accuracy. Left putamen volume was negatively correlated with processing speed. Those correlations were not observed among adults in the control group.
Cortical thickness did not differ between the hypoparathyroidism and control groups. Cortical thickness in the superior temporal sulcus and parietooccipital sulcus was bilaterally correlated with executive functions for those with hypoparathyroidism.
Researchers said longitudinal studies should be conducted in which adults with hypoparathyroidism are evaluated before surgery and at least 1 year after surgery to better assess changes in cognitive performance and brain structure.
“Moreover, such a longitudinal design could also include parathyroid hormone replacement therapy in a randomized controlled study to reveal whether cognitive decline and cortical and subcortical atrophy can be diminished — thus improving the quality of life for hypoparathyroidism patients,” the researchers wrote.
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