diff --git a/lib/crypto/algorithms/megolm.js b/lib/crypto/algorithms/megolm.js
index 695cb615d..b156d5d59 100644
--- a/lib/crypto/algorithms/megolm.js
+++ b/lib/crypto/algorithms/megolm.js
@@ -171,9 +171,9 @@ MegolmEncryption.prototype._prepareNewSession = function(room) {
  * @param {string} session_id
  *
  * @param {Object<string, Object<string, boolean>|boolean>} shareMap
- *    Map from userid to true (meaning this is a new user in the room, so all
- *    of his devices need the keys), or a map from deviceid to true (meaning
- *    this user has one or more new devices, which need the keys).
+ *    Map from userid to either: true (meaning this is a new user in the room,
+ *    so all of his devices need the keys); or a map from deviceid to true
+ *    (meaning this user has one or more new devices, which need the keys).
  *
  * @return {module:client.Promise} Promise which resolves once the key sharing
  *     message has been sent.