Method of Detecting Neurological Disease

A method for providing a differential diagnosis of a patient with progressive supranuclear palsy (PSP) from a patient with Parkinson's disease (PD) that comprises the steps of:

• a) identifying in a patient to be diagnosed with one or the other of PSP or PD a plurality of at least partially repetitive eye movements that over time define square wave jerks within a sequence of eye movements, each square wave jerk of the plurality of square wave jerks being defined by a first horizontal saccadic movement that moves the eye away from a fixation target that is followed by a corrective saccadic movement towards the target shortly thereafter;
• b) determining the saccade rate of the patient;
• c) comparing the saccade rate with a threshold value for normal healthy subjects or other patients with PD;
• d) identifying the presence of PSP or PD in the patient to be diagnosed based upon the comparison of the saccade rate with the threshold value whereby a saccade rate statistically different from the threshold value of normal subjects or PD patients identifies the patient to be diagnosed as having PSP, whereas a saccade rate that is statistically different from the threshold value of normal subjects or PSP patients identifies the patient as having PD.

An apparatus that detects and characterizes eye movements of a subject, for the differential diagnosis of a patient with progressive supranuclear palsy (PSP) from a patient with Parkinson's disease (PD) comprising:

• a processor that processes a sequence of repetitive, involuntary eye movements, each of the plurality of involuntary eye movements defined by a first horizontal saccadic movement that moves the eye away from a fixation target followed by a corrective saccadic movement towards the target shortly thereafter;
• a processor that measures vertical components associated with the plurality of repetitive eye movements;
• a processor that compares the vertical components with a threshold value;
• and
• a processor that differentially identifies progressive supranuclear palsy from Parkinson's disease based upon the comparison of the vertical component with the threshold value.

A system that detects and characterizes eye movements of a patient, for the differential diagnosis of a patient with progressive supranuclear palsy (PSP) from a patient with Parkinson's disease (PD) comprising:

• eye movement processing apparatus that identifies a plurality of square wave jerks within a sequence of repetitive eye movements, each of the plurality of square wave jerks defined by a first horizontal saccadic movement that moves the eye away from a fixation target followed by a corrective saccadic movement towards the target shortly thereafter;
• a processor that measures vertical components associated with the plurality of square wave jerks;
• a processor that compares the vertical components with a threshold value or the saccade rate;
• and
• a processor that identifies PSP or PD based upon the comparison of the vertical component with the threshold value.