Presumably the accucheck is for measuring changes in circulating glucose? I think the problem that you face with this approach and similarly if you decide to use salivary cortisol measures - in combination with an ELISA detection method is variability. Both end points vary enormously within individuals. This can really mess with the power of the experiment - so in moving forward with this consider as a primary question what your effect size is. Probably the best and highest quality way is to insert an indwelling cathether and draw blood for radioimmunoassay measurements of your hormone of interest every 15-60 minutes throughout the procedure. If you search through the human literature on those using the trier stress test you will find some excellent examples of this approach.

Hi Andrea, I think there are two different ways to go, and I think the best option it to cover both. One is the biomarker route and the other is an instrument. If you are going to ask the subjects to do a swab for a biomarker, it certainly isn't a big deal to have them fill out an inventory at the same time. I am no great expert on cortisol, but the biggest problem is that it has normal variation throughout the day and also responds relatively quickly to stress. So for starters, you'd probably need cortisol swabs upon aweakening to have as much as a standardized measure as possible, but you'd have to look to other studies to see how many assays they do and when to detect long-term trends. Off the top of my head, I can't think of an instrument to pick up relatively chronic stress, but there are numerous measures out there, several used in standard longitudinal study and with few items, that you could chose from. You'd probably want one phrased in something like a one-week time frame to pick up changes in the stress level. Bob

Aside from Biomarkers you can always survey subjective measures of stress. Use a questionnaire like the Perceived Stress Questionnaire PSQ: http://www.ncbi.nlm.nih.gov/pubmed/15673628

(or the POMS http://www.ncbi.nlm.nih.gov/pubmed/10100834)

It's done in 4 minutes, it's free (as far as I know) and it could catch increases in stress during an exam period in one of my ongoing studies. Of course you have to discuss social desirability bias etc...

We use an important method that soon will be also ready as commercial software. In detail I use HRV . We examine subjects under suitable experimental-psychological conditions recording the R-R signal. We obtain direct and valuable quantification of the stress by an index ranging from 0 to 1. The normal value is in the range 0.6-1 so that decreased values enable to estimate the index of dynamic stress in a very satisfactory manner.Let me know if you are interested.

I have not done clinical testing yet, only experiments using neonatal rats. However, I read somewhere that an easy way to measure stress in humans is to measure the length of hair. Hair grows at a rate of ca. 1 cm per month, so putatively stress should affect hair growth and thus its length. Whilst this approach would be non-invasive and very cost-efficient, I do not know how scientifically sound may be, but you could run a simple experiment and, depending on your results, see whether you can progess from that. Good luck.

There is a lot of variability in salivary cortisol, but repeated samples can be very useful. Take one at waking, one 30-min post wake, and one at bedtime, as well as one at the time of day you plan on running your stress experiment. Do this three times in a week and average those values.

Under chronic stress, you should see a flattening of the daily curve because of the rise in evening cortisol. The biggest problem I have had with this measure is the reliability of the participants in providing saliva at the appropriate times.

In acute stress, salivary cort can peak anywhere from 15-40 minutes after the stressor. Doing the stressor in the afternoon will help avoid the huge morning fluctuation.

Galvanic skin response is also always an option for acute stress.

I do not agree . It is well known that cortisol dosage gives only problems at the end. It is well known that R-R reflects the actual condition and , having a good method, it gives valuable results.

Only problems that result in a solid publication record.

I'm not arguing with HRV. I've used it myself. I'm presenting an option, as requested.

We now as the problem of the stress is so important in treatment of a subject. I only say that psychophysiological studies may help us in a so important sector for the patients and for the service. Psychophysiology has delineated in the last years the great role of the analysis of the R-R signal with particular enphasis in psychological disorders. Of course R-R has also a basic theoretical foundations and to day may be estimaed with high accuracy. Still, a lot of research has been developed. So, my indication is that we cannot lose this new and important advance . We have to ove in this direction. Of course this is only my modest opinion but based on several years of research and service.

You can look at diurnal changes in salivary cortisol, which is quite non-invasive. Stress changes the diurnal rhythm, which is relatively easy to capture. You can also look at beta-amylase activity in saliva, which is an indirect measure of noradrenergic activity in the body.

Why do you not inform us about your direct experience. Inform us on the methodology and on the results and you and we will see finally with the eyes how good are th e results that you are obtaining

Simply ask the human :-)

there are some issues with self reports, but this should not discourage you from using a method that is comparatively noninvasive and cost effective

my question is as it follows. Cortisol dosage while responding actually to basic valid principles, gives problems in the dosage and , in addition, is not so valuable in giving a ceratin index of stress. Si I would like to select other methods. HRV is dominant in psychophysiology as certainly you well know.

I too am very interested in HRV. There is an inexpensive recording instrument which has been authenticated called the eMotion HRV, BY Mega Electronics; it needs no chest strap and can store 5 days data, which can be downloaded to computer by a cable. Comes with own software for analysis of time- or frequency-domain. Be aware that there is a recent article by Billings which is critical of the measure; as well as suggestions (Vaschillo) that measures of "coherence" between breath rate and R-R may give useful info on stress levels.

Peter , you certainly know that the R-R represents one of the most complex biological signals in medicine. We have to day a lot of instruments able to perform psychophysiological measurements. The problem I see , generally speaking, is that psychophysiology is valuable if and only if at the basis we realize robust methods.of investigation Certainly you know that by the R-R we are in presence of a signal that is not periodic, not stationary and non linear.. We need robust methods to investigate it in normal subjects. It becomes an hard problem in pathological conditions and /or in presence of psychological or psychiatric disorders. This is the reason because we , first of all, have realized a robust method of investigation and consequently a proper designed device able to solve the problems. To quantify VLF,LF,HF bands using proper methodologies for evaluation of dynamic stress. The result of course is given on line using plethysmography.

Hi Andrea

Colleagues of mine at the Westmead Psychotherapy Centre, led by Anthony Korner have been looking at HRV in the very delicate situation of the Psychotherapy interview and found that subjects were ok with using a band around the chest as interface. However I also am aware the My Brain Solutions have the simple ear clip device for ECGs to determine HRV for using their breathing strategy Mycalmbeat and this is quite a non-invasive interface.

As to analysing the data, the colleagues above have found a simpler analysis model for the RR - see: Comput Methods Programs Biomed. 2012 Oct;108(1):53-67. doi: 10.1016/j.cmpb.2012.01.002. Epub 2012 Feb 10.

Increasing sensitivity in the measurement of heart rate variability: the method of non-stationary RR time-frequency analysis.

Melkonian D, Korner A, Meares R, Bahramali H.

I also agree that in parallel asking the human subject is a good idea (say the DASS by Lovibond and Lovibond) and then to correlate with the physiological data. However you might also consider an attachment assessment as people who are dismissive tend to downplay or be unaware of their stress. Pen and paper measures are different to the gold standards (which are interview-based, the AAI) but if your study population is normative the data could still be useful. Consider the RSQ or derivatives (Bartholomew and Horowitz, 1991)

good luck with your project!

The HeartMath as well as the Breath Heart people all use ear-or finger-clips for their biofeedback devices; I have been told by an expert here that these clips are not reliable enough for clinical data. The eMotion HRV sensor I mention above is clinical quality, and is the only such sensor I was able to find which does not require a chest strap.

Dear Layola, you are right following tachogram during psychotherapy. Unfortunately this is the custom of psychotherapist to follow the subject during his/her dialogue but it should be so , I suggest. To have an on line indication of psychophysiological factors is always a very satisfactory methodology if we all agrre to give credit to such discipline. I suggest always also monitoring GSR during psychotherapy in tone and phase and evaluate with satisfactory methodlogies.

Concerning the stress our methodology is obviously non invasive . The part9icular advantage of our method is that , in order to quantify a good index of dynamic sterss, you have to record two tachograms .. and this is the basic and important feature of our method. Soon after, sorry if I repeat, the other basic requirement is that you must have a robust method for investigation and analysis and this in fact has been the basic effort by us in these years. We have in fact to rememebere that R-R signal records all the psychological disorders and thus you have the possibility to discriminate with care the true component that is due to the stress condition.

Breath. As we know in the R-R PSD spectrum we have three bands, the VLF, the LF that is due mainly to sympathetic and vagal modulations and the HF that is due to vagal modulation. It is related to breath. Consequently controlled respiration gives increasde in vagal modulation. To reach this objective to increase vagal activity obviously one must operate under suitable condition so that respiration results in phase with HR and in opposition of phase with SBP. In thsi conditions also BRS give their opyimum contribution. And we know that BRS are so important. Consequently, also in this case a robust methodology is required that in fact we use.

Sorry to be ignorant, what are SBP and BRS?

I understand vagal control results in correct RSA, manifested in increased HF power; I understand that paced breathing will increase HF power. This must be at least partly an effect independent of change in vagal tone, since as the breath is more rhythmic any HR modulation linked to it will narrow its frequency peak. This does not per se indicate increased vagal tone. Is there independent evidence (from other indications such as GSR, EEG, EMG, BP) that paced breathing (or biofeedback-guided 'coherent breathing practice') actually changes vagal tone, or is this merely an artifact? If this does happen (and I suspect it does), what is the actiually mechanism?

I also wonder about using a plethysmograph to measure both chest and abdominal breathing, I speculate the ratio might indicate sympathetic/parasympathetic balance?

SBP : Systolic Blood Preassure. BRS : BaroReflexSenitivity.