Your Nerve Health Score (NHS) or Electrodermal Activity Score (EDA) can fluctuate based on the conditions when taking your measurement. When your scale is not able to accurately assess your score based on these fluctuations, a Guided Scan might be required in order to get a reading. A Guided Scan replicates the environment of a medical consultation to ensure optimal weigh-in conditions. 

A Guided Scan can be launched at any time from the application. To do this, follow these steps:

1. Open the Withings App.
2. Select your most recent NHS or EDA measurement in the Home tab to access its measurement graph.
   You can also select the Measure tab, scroll down, and then select either Nerve Health or Electrodermal Activity to access the graph. 
3. Scroll to the bottom of the measurement graph screen to 'Options' and select Take a Guided Scan.

A Guided Scan will provide the following instructions: 

1. You should have been on your feet throughout the past hour.
2. Remove your shoes prior to taking a measurement, but ensure that you are not barefoot for more than 10 minutes before weighing yourself.
3. Make sure that the scale & your feet are dust-free.

Note: To get the most accurate measurements, always take them under the conditions described in the Guided Scan instructions. Ignoring guidelines can impact your result.