Mild Cognitive Impairment (MCI) in Type 2 Diabetes: Healthy Aging? or Transitional State to Dementia

Diabetes mellitus is a global epidemic that has preclinical sequelae with different types of complications, some known and others emerging. Mild cognitive impairment, otherwise known as central neuropathy, is an emerging complication. It is termed as a "new diabetic complication." Cognitive function is a comprehensive term that refers to memory and non-memory functions such as attention, concentration, executive function, abstract thinking, language, calculation, and visuospatial skills. These non-memory functions are thought to help initiate, sustain, and complete complex tasks.

There are studies that mention that in diabetics, non-memory functions are affected first, followed by memory functions. This leads to a dilemmatic problem where the patient doesn't understand that they are suffering from cognitive impairment because these problems are less pronounced at that time. These problems, such as lack of interest and shorter attention span, are mild and don't have a significant impact on daily lifestyle. Therefore, mild cognitive impairment remains hidden like an iceberg. Unfortunately, it becomes bothersome when it has already progressed to a higher level, and the patient starts experiencing memory problems and forgetfulness, which then alarms them to visit a doctor.

There is various published literature about the risk of mild cognitive impairment in diabetics and non-diabetics. The risk of cognitive impairment is two times higher in hyperglycaemic individuals compared to normoglycemic individuals. An increase in circulating blood sugar levels has an impact on blood circulation within the brain. It leads to damage to the vessels supplying the area responsible for cognition, specifically the prefrontal cortex, commonly known as vascular dementia. Annually, 10-15% of patients with diabetes and cognitive decline convert to dementia. Therefore, prompt detection of cognitive problems at an early stage is essential.

A common question arises regarding the early-stage cognitive impairment, as it is not that evident. By the time it progresses, it reaches the preclinical stages of dementia. So, what are the appropriate signs to report to a healthcare professional? One should understand and consider four factors when reporting cognitive impairment to a doctor. First, the duration of diabetes, as the longer the duration, the higher the risk. Second, prolonged hyperglycaemia despite being on oral medication. Third, age, as older adults are at higher risk. Fourth, patients with insulin-dependent diabetes are at a higher risk of developing cognitive impairment. The treatment of cognitive impairment is a holistic approach. Family and caregivers should understand that patients with diabetes are not being irresponsible or forgetful on purpose. We should maintain an empathetic approach towards such behaviour, as they might be developing cognitive impairment.

Initially, various regulatory bodies did not recommend screening for cognitive decline in older adults, as it didn't have any effect on patient-related health outcomes. However, according to the American Diabetes Association 2021 guidelines, screening of older adults with diabetes has been added. This will help prevent the transition of mild cognitive impairment to dementia. As mentioned earlier, the treatment of cognitive impairment in diabetes is a holistic approach. A consulting physician plays an important role in monitoring glucose levels at regular intervals, which has a positive impact on cognition.

Cognitive physiotherapy also plays an essential role in such patients. There are many treatment options available these days, including brain gym training, the application of transcranial direct current stimulation, cognitive-behavioural therapy, etc. Unfortunately, patients with diabetes and cognitive decline, along with physicians and diabetologists, are less aware of physiotherapeutic approaches in managing cognitive impairment.

However, at Dr. D. Y. Patil College of Physiotherapy, we practice various methods of cognitive rehabilitation, including the application of Transcranial Direct Current Stimulation (TDCS), general motor coordination exercises, brain gym training, aerobic exercises, and yoga therapy. At our OPD, we routinely screen diabetic patients using physiotherapy methods.

Key Message:

Be patient if any diabetic patients are forgetful, irresponsible, or less attentive. They might have problems with cognition. Do not overlook or ignore mild signs such as forgetting to take medicine or not being able to concentrate in the workplace. Slowed speed in thoughts is an alarming sign to visit a doctor.

Regular screening for cognition should be conducted by physicians and diabetologists to prevent further progression of this mild cognitive impairment to neurodegenerative disorders. Additionally, physiotherapy consultation is essential for the rehabilitation of such patients. A comprehensive treatment that includes controlling glucose levels with physiotherapy would yield excellent results in managing and preventing the transition from mild cognitive impairment to dementia.

References:

1. Mohammad Abdul Hannan Hazari et al., "Cognitive Impairment in Type 2 Diabetes Mellitus," International Journal of Diabetes Mellitus, 2011.
2. Eileen M. Moore et al., "Increased Risk of Cognitive Impairment with Diabetes is Associated with Metformin," Journal of Diabetes Care, 2013.
3. Susan B. O'Sullivan, "Physical Rehabilitation," Chapter 15, 5th edition, pages 1222-1414.
4. Natalia Sokolowska et al., "Diagnosis of Mild Cognitive Impairment," July 2015.
5. Hancock et al., "Short Dementia Screening Tests Suitable for Primary and Secondary Care," 2011.
6. Vijay Pratap Singh, "Psycho-neuro-endocrine-immune Mechanisms of Action of Yoga in Type 2 Diabetes," Indian Council of Medical Research, ICMR.
7. Valenzuela and Sachdev et al., "Cognitive Training Approaches to Protect Brain Health in Later Life: Case-control Studies," 2011.
8. Husseini Fatemeh, "Effect of Brain Training on Cognitive Performance in Elderly Women Diagnosed with Mild Cognitive Impairment," Caspian Journal of Neurological Sciences, 2016; 2(7): 25-31.
9. Zimerman M. et al., "Modulation of Training by Single-Session Transcranial Direct Current Stimulation to the Intact Motor Cortex Enhances Motor Skill Acquisition of the Paretic Hand," Stroke, 2012; 43(8): 2185-2191.