The most common neurodegenerative diseases worldwide are Alzheimer's and Parkinson's. These diseases occur when the brain and peripheral nervous system gradually lose their function or result in the death of nerve cells.  Thus, a healthy life depends on the early detection of neurodegenerative illnesses. Because of the high expense, limited sensitivity, and drawbacks of conventional diagnostic techniques, currently available biosensor technologies enable the development of alternative techniques for the early identification of neurodegenerative illnesses. Biosensors make it possible to quickly, sensitively, and usually non-invasively identify biomarkers of certain neurodegenerative disorders by using bioreceptors and transducers (optical, piezoelectric and electrochemical techniques). Together with these biomarkers, exosomal microRNA and Tau oligomer biomarkers also make effective detection possible. A thorough analysis of research employing biosensor technology for the early detection of neurodegenerative illnesses is provided in this section. These include discussion of several biosensor kinds, their operation, clinical uses with various immobilization techniques, and upcoming advancements.