According to Dr. Ridha Arem in his book The Thyroid Solution, low thyroid can leave one unable to remember details, names or even events. An imbalance of thyroid hormones in the brain cause a definite change in how the brain processes information and in one's ability to comprehend and retain information. Even a mild imbalance can effect mental processes. Depression also effects cognitive function. Those with thyroid disease are often depressed.
Seniors are also often depressed and grieving over losses in their lives.
See your medical practioner and request that thyroid function tests are included in the diagnostic process. Used under License.