diff --git a/epicardium/ble/hid_work.c b/epicardium/ble/hid_work.c
index 9f59b6cfe8e917203e4b22fb4478a00069e404ee..b0158feaa039af9fa2dbe35a6701c47a0ae95058 100644
--- a/epicardium/ble/hid_work.c
+++ b/epicardium/ble/hid_work.c
@@ -325,7 +325,7 @@ void epic_hid_keyboard_report_event(
  */
 /*************************************************************************************************/
 void epic_hid_mouse_report_event(
-	uint8_t buttonMask, uint8_t xDisplacement, uint8_t yDisplacement
+	uint8_t buttonMask, int8_t xDisplacement, int8_t yDisplacement
 ) {
 	dmConnId_t connId;
 
diff --git a/epicardium/epicardium.h b/epicardium/epicardium.h
index 80102ee44d990d294fe6442efa8c20aaff8dad47..2ca919c196b87a55ea5b7cffa518220fe1fce925 100644
--- a/epicardium/epicardium.h
+++ b/epicardium/epicardium.h
@@ -2334,8 +2334,8 @@ API(API_HID_KEYBOARD_REPORT, void epic_hid_keyboard_report_event(
 ));
 API(API_HID_MOUSE_REPORT, void epic_hid_mouse_report_event(
 	uint8_t buttonMask,
-	uint8_t xDisplacement,
-	uint8_t yDisplacement
+	int8_t xDisplacement,
+	int8_t yDisplacement
 ));
 #endif /* _EPICARDIUM_H */