Cognitive Impairment (CI)

The goal of this clinical trial is to examine if non-invasive brain stimulation (NIBS) can enhance cognitive function with chronic obstructive pulmonary disease (COPD) population. The main questions it aims to answer are: * What is the possibility effect of using the NIBS on cognitive functions as well as the cardiopulmonary parameters in COPD population? * What is the relation between cognitive function parameters and cardiopulmonary parameters in COPD population who suffer from cognitive impairment (CI)? Researchers will compare NIBS to a sham-NIBS to see if NIBS works to improve cognitive function in COPD population. Participants will: Receive NIBS or a sham-NIBS 5 sessions/week for 3 weeks for 20 min each session. Visit the clinic at the beginning for baseline assessment then after the completion of the 3 weeks to reassess them. Outcome measures for cognitive parameters and pulmonary parameters will be taken pre and post NIBS intervention