Neuropsychologists in a clinical setting use assessments involving interviews and a wide range of tests to determine cognitive abilities. Other ways to study include...

Electroencephalography (EEG) & magnetoencephalography (MEG) record the electrical or magnetic brain activity. They are used to test anomalies in cognitive processes while a person is at rest.

Transcranial magnetic stimulation (TMS) & Transcranial direct current stimulation (tDCS) can be used to interfere with a function or facilitate it. Has been used to improve function in patients with Alzheimer's.

Computerized tomography (CT scan) studies the brain structure.

Positron Emission Tomography (PET) is used to research the links between the brain and cognition.