Patients with chronic hypoparathyroidism following surgery for thyroid cancer do not show significant cognitive impairment overall, but those with lower blood calcium levels have shown disturbances in function cognitive, according to one study.
Specifically, patients with lower calcium levels had impairments in visuospatial attention, semantic memory (general knowledge memory), and executive function – a set of cognitive skills used to manage daily life. .
The study, “Serum calcium levels are associated with cognitive function in hypoparathyroidism: a neuropsychological and biochemical study in an Italian cohort of patients with chronic post-surgical hypoparathyroidismwas published in the Endocrinological Investigation Journal.
Hypoparathyroidism is characterized by a deficiency of parathyroid hormone (PTH), an important regulator of calcium levels in the blood.
As a result, patients suffer from hypocalcemia, or low calcium levels, which cause a range of symptoms including kidney problems, poor bone quality, muscle problems and mental health issues.
Cognitive symptoms, such as brain fog, trouble concentrating, memory loss, depression, anxiety, and fatigue may also occur. It is thought that these symptoms may stem from a calcium deficiency in the brain, where calcium is essential for the proper functioning of nerve cells.
Study investigates relationship between blood calcium levels and cognition
Researchers in Italy wanted to assess cognition in people with chronic hypoparathyroidism and determine the relationship between blood calcium levels and cognition.
The study participants had all undergone surgery for thyroid cancer at the researchers’ hospital and were in remission. All were stable on thyroid hormone replacement therapy. Individuals were assessed once for blood calcium levels and cognition between March 2018 and July 2020.
The analysis included 33 people – 69.7% female – with a median age of 52 who suffered from chronic hypoparathyroidism after their surgery. These patients were all receiving standard treatment consisting of calcium and vitamin D supplementation.
Also included were 24 people – 83.3% female – with a median age of 53 who did not develop hypoparathyroidism after surgery and served as a control group.
Cognitive assessment revealed no significant differences between groups when data were adjusted for age and education, indicating post-surgical hypoparathyroidism is not generally related to dysfunction cognitive.
In people with hypoparathyroidism, lower blood calcium levels have been observed to be associated with poorer visual-spatial attention, as measured by a Trail Making Test-A (TMT-A), and less good semantic memory and executive function, as measured by the semantic test. fluidity test. This association was not observed in the control group.
Overall, patients with hypoparathyroidism with calcium levels at or below a median of 8.9 milligrams per deciliter (mg/dl) had lower test performance in TMT-A and semantic fluency compared to to those with levels above 8.9 mg/dl. Likewise, those below this median had lower performance in the TMT-A compared to the control group.
“We show that patients with chronic diseases [post-surgical hypoparathyroidism] treated with conventional therapy do not show severe cognitive impairment,” the researchers wrote.
“Nevertheless, certain cognitive functions such as visuo-spatial attention, executive function and semantic memory seem to be modulated by [blood calcium] and threatened by its low levels,” they added.
The lack of general cognitive impairment seen in patients with post-surgical hypoparathyroidism contrasts with previous findings, the researchers noted. However, these studies included patients with hypoparathyroidism with no known (idiopathic) cause, which could explain the difference, the team suggested.
Calcium performs a number of essential functions in the brain that could explain the cognitive symptoms seen in patients with low levels.
For example, calcium enables a group of cells called astrocytes to take over information processing. Such integration of information may be disrupted in patients with low calcium levels, leading to cognitive problems, the team theorized.
Alternatively, a growing body of evidence suggests that disturbances in PTH itself could affect cognition, they noted.
Future studies with more patients and follow-up assessments could help broaden the findings, the researchers noted, adding that subtle cognitive changes “could be better studied using more complex tools, such as MRI.”