Partial withdrawal of levothyroxine treated disease leads to brain activations and effects on performance in a working memory task: A pilot study

J Neuroendocrinol. 2019 Apr;31(4):e12707. doi: 10.1111/jne.12707. Epub 2019 Apr 10.


Hypothyroidism is associated with memory impairments. The present study aimed to evaluate the effects of partial withdrawal of levothyroxine on working memory tasks and brain function. Fifteen subjects under long-term levothyroxine substitution as a result of complete hypothyroidism participated in the present study. Functional magnetic resonance imaging (MRI) was performed using a working memory task (n-back task) and neuropsychological tests were performed before and 52-54 days after the induction of subclinical hypothyroidism by reducing the pretest levothyroxine dosage by 30%. Reaction time of subjects under partial levothyroxine withdrawal was significantly longer and less accurate with respect to solving the working memory tasks. Functional MRI revealed significant activation changes after medication withdrawal in the cerebellum, insula, parietal, frontal, temporal and occipital lobes, lingual gyrus, and the cuneus. Partial withdrawal of levothyroxine may lead to deficits in a working memory task and to an activation of brain areas associated with working memory ability.

Keywords: functional MRI; hypothyroidism; memory; n-back task; thyroid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / physiopathology*
  • Female
  • Humans
  • Hypothyroidism / complications
  • Hypothyroidism / drug therapy*
  • Hypothyroidism / physiopathology*
  • Magnetic Resonance Imaging
  • Male
  • Memory / physiology*
  • Memory Disorders / etiology
  • Memory Disorders / physiopathology
  • Middle Aged
  • Neuropsychological Tests
  • Pilot Projects
  • Reaction Time / physiology
  • Thyroid Hormones / blood
  • Thyroxine / administration & dosage*


  • Thyroid Hormones
  • Thyroxine