Electrotactile Frequency, Amplitude, and Temporal Gap Discrimination in Young Adults, Older Adults, and Stroke Survivors

Inclusion Criteria: * Young Adult Group: * Age 19 to 54 years. * Has tactile sensation in the hands and fingers. * Provides voluntary written informed consent personally or through a legally authorized representative, if applicable. Older Adult Group: * Age 55 to 70 years. * Has tactile sensation in the hands and fingers. * Provides voluntary written informed consent personally or through a legally authorized representative, if applicable. Stroke Patient Group: * Age 19 years or older. * Diagnosis of ischemic or hemorrhagic stroke. * Stroke confirmed by CT or MRI. * Stroke accompanied by proprioceptive sensory impairment. * Residual tactile sensation in the fingertip. * Provides voluntary written informed consent personally or through a legally authorized representative, Exclusion Criteria: * Young and Older Adult Groups: * Absence of tactile sensation in the hands or fingers. * Congenital deformity of the hands or fingers. * Presence of a major pre-existing neurogenic disease. * Presence of a major psychiatric disorder, such as major depressive disorder, schizophrenia, bipolar disorder, or dementia. * Implanted pacemaker. Stroke Patient Group: * Difficulty communicating due to K-MMSE score \< 23, severe language impairment, or similar condition. * Absence of tactile sensation in the hands or fingers. * Congenital deformity of the hands or fingers. * Severe pain during elbow joint or finger movement. * Progressive or unstable stroke. * Presence of hemispatial neglect…