Biofeedback system

1. An apparatus for providing muscular biofeedback, comprising:

facewear supporting biosensors arranged such that, in use, the biosensors are situated for detecting activity of a predetermined set of facial muscles;

a feedback unit integral with the facewear for providing biofeedback to a wearer of the facewear; and

a control unit coupled to the biosensors and the feedback unit and arranged to identify patterns in the signals from the biosensors characteristic of one or more predefined imbalances in muscle activity between the left and right sides of the face; wherein the control unit is configured to identify a pattern in the signals from the biosensors characteristic of a first predefined imbalance in muscle activity between the left and right sides of the face by comparing the activity of predetermined corresponding facial muscles on the left and right sides of the face, and responsive to identifying the first predefined imbalance, cause the feedback unit to provide different biofeedback to each side of the face in correspondence with the first predefined imbalance, the biofeedback provided to a particular side of the face being provided only to that respective side of the face.

2. The apparatus as claimed in claim 1 , wherein the facewear comprises eyewear and the feedback unit comprises corrective or non-corrective lenses arranged so as to in use be located over the eyes of the wearer, the lenses being configured to provide visual biofeedback by means of changes in the color or transmittance of one or both of the lenses.

3. The apparatus as claimed in claim 1 , wherein the predetermined set of facial muscles includes the posterior auricular muscle and the control unit is configured to infer the activity of a zygomaticus muscle from the activity of the posterior auricular muscle on the same side of the face.

4. The apparatus as claimed in claim 3 , wherein the control unit is configured to identify a pattern in the signals from the biosensors characteristic of a first predefined facial expression and to, on identifying the pattern in the signals from the biosensors characteristic of the first predefined facial expression, cause the feedback unit to provide biofeedback indicative of the first predefined facial expression.

5. The apparatus as claimed in claim 1 , wherein the control unit is configured to identify that the pattern in the signals from the biosensors is characteristic of the first predefined imbalance in muscle activity if the signals from the biosensors indicate that the asymmetry between the activity of the predetermined corresponding facial muscles on the left and right sides of the face exceeds a predetermined threshold for at least a predetermined minimum duration.

6. The apparatus as claimed in claim 5 , wherein, if the duration of time when the control unit causes the feedback unit to provide biofeedback falls below a predetermined duration, the control unit is configured to automatically decrease the predetermined threshold.

7. The apparatus as claimed in claim 5 , wherein the control unit is configured to store information defining which side of the face the first predefined imbalance is primarily associated with and to, in use, provide biofeedback at least primarily to that defined side of the face.

8. The apparatus as claimed in claim 5 , wherein, if the frequency of occurrence of periods of time when the control unit causes the feedback unit to provide biofeedback falls below a predetermined frequency of occurrence, the control unit is configured to automatically decrease the predetermined threshold.

9. The apparatus as claimed in claim 5 , wherein the control unit is configured to provide one or more of visual, auditory or vibrational biofeedback to the eye or ear of each side of the face in correspondence with the first predefined imbalance.