diff --git a/Documentation.md b/Documentation.md
index 072cc07..7192ff1 100644
--- a/Documentation.md
+++ b/Documentation.md
@@ -79,6 +79,7 @@ Builds a trial with a onscreen message, optional buttons and optional phtodiode
 | duration | <code>number</code> | The trial duration in milliseconds. |
 | config | <code>object</code> | The configuration object for USE_PHOTODIODE, IS_ELECTRON and USE_MTURK flags. |
 | message | <code>string</code> | Onscreen message to be shown in the trial, if not set default text is empty. |
+| onstart | <code>boolean</code> | True if the message is to be display on start of the trial. False if the message needs to be in the stimulus.(default: false) |
 | responseEndsTrial | <code>boolean</code> | True if the trial ends on response,false if the trial waits for the duration, by default false value. |
 | taskCode | <code>number</code> | Task code to be saved into data log and for pdSpotEncode, which by default is null and is passed when config has USE_PHOTODIODE set true. |
 | numBlinks | <code>number</code> | Number of times the pulse needs to be repeated for photodiode box, when USE_PHOTODIODE is set true. If not set, by default is 1. |