Refer to figure.
ICAO Annex 14 Volume I 
3. Calculation of declared distances 

3.5 Where a runway has a displaced threshold, then the LDA will be reduced by the distance the threshold is displaced, as shown in Figure A-1 (D). A displaced threshold affects only the LDA for approaches made to that threshold; all declared distances for operations in the reciprocal direction are unaffected.

A displaced threshold is a threshold that is not located at the extremity of a runway. The portion of the runway before the displaced threshold is not available for landing, but may still be used for take-off. Therefore, this portion remains included in the applicable take-off declared distances; it is not an extension of the TORA.

• TORA is the take-off run available.
• TODA is TORA plus clearway. 
• ASDA is TORA plus stopway.

Because the portion before the displaced threshold remains available for take-off, the displacement of the threshold does not reduce TORA, TODA or ASDA.

For landing, however, the LDA begins at the displaced threshold. Because the portion before the displaced threshold cannot be used for landing, the further the threshold is displaced into the runway, the shorter the LDA becomes.

The arrows preceding the displaced threshold identify the portion of runway before the threshold. They do not add any new length or constitute an extension to the declared take-off distances.

Therefore, in the regulatory terminology of ICAO Annex 14, a displaced threshold affects only the LDA for approaches made to that threshold.