BME100 f2014:Group31 L3

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Owwnotebook icon.png BME 100 Fall 2014 Home
Lab Write-Up 1 | Lab Write-Up 2 | Lab Write-Up 3
Lab Write-Up 4 | Lab Write-Up 5 | Lab Write-Up 6
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Name: Charles Bolton
Name: Andy Chang
Name: Michael Chatarachanwong
Name: Afshin Isadvesta
Name: Andrew Liu
Name: Jimmy Xu


Descriptive Statistics

Temperature Readings

PreWalk Gold Standard Mean: 97.43860606, Std. Dev (Farenheit)0.782922836, Count:164, Std. Error 0.061136002

Walk Gold Standard Mean: 97.41843434, Std. Dev (Farenheit)0.882974589, Count:395, Std. Error 0.044427273

CD Gold Standard Mean: 97.87127273, Std. Dev (Farenheit)0.801682045, Count:164, Std. Error 0.06260085

PreWalk Spree Mean: 101.4727273, Std. Dev (Farenheit)2.621588693, Count:164, Std. Error 0.204711684

Walk Spree Mean: 104.4292929, Std. Dev (Farenheit)3.027728481, Count:395, Std. Error 0.152341553

CD Spree Mean: 102.8909091, Std. Dev (Farenheit)1.993948717, Count:164, Std. Error 0.155701236

Pulse Readings

Prewalk Gold Mean: 79.78195489, Std. Dev (bpm): 13.34242399, Count: 133, Std. Error: 1.156934886

Prewalk Spree Mean: 80.70676692, Std. Dev (bpm): 14.95943097, Count: 133, Std. Error: 1.297147174

Walk Gold Mean: 100.6028571, Std. Dev (bpm): 21.38310644, Count: 350, Std. Error: 1.142975117

Walk Spree Mean: 101.1628571, Std. Dev (bpm): 21.57506501, Count: 350, Std. Error: 1.153235734

Cooldown Gold Mean: 85.10204082, Std. Dev (bpm): 18.02461585, Count: 147, Std. Error: 1.486645259

Cooldown Spree Mean: 84.14965986, Std. Dev (bpm): 17.2873989, Count: 147, Std. Error: 1.42584063

  • Note: For the Pulse Readings, some data was not included from groups 5, 8, 9, 10, 11, 13, 15, 26, 29, and 31 due to partially complete or incorrectly entered data. If one value (for example, Spree) was incorrectly entered or missing, its corresponding (Gold Standard) value was omitted.


Gold vs Spree Temp.jpg

Gold vs Spree Heart Rate.jpg

Dataset and Statistics

Because the experiment compared only two data sets (the gold standard and the Spree device), a t-test was used. The t-test itself was uncoupled because the data sets were not directly sequential to each other. In other words, there were no (before-and-after measurements).

Pulse Overall T Test: 0.909374538

Pulse Overall Pearson's Correlation: 0.805209108

Temperature Overall T Test: 0.0

Temperature Overall Pearson's Correlation: 0.028772406

Since the Temperature T-Test produced a result that was less than 0.05, we conclude that there is a statistically significant difference between the Gold Standard and Spree measurements. That isn't good for the Spree because if it were a good and accurate device, then it would yield results similar to the Gold Standard and thus there would be no significant difference between the two devices.

Since the Pulse T-Test produced a result that was greater than 0.05, we conclude that there is no statistically significant difference between the Gold Standard and Spree measurements. That is good for the Spree, because it means it is almost on par with the Gold Standard in terms of accuracy.

Because the Temperature Pearson's correlation test produced a value that was close to 0, we conclude that there is no correlation between the two sets of measurements.

Because the pulse Pearson's correlation test produced a value that was close to 1, we conclude that there is positive correlation between the two sets of measurements.


In the comparison between the gold standard and the Spree health monitor, there were significant differences found between the temperature measurements. These differences can be attributed to the general scale used to measure temperature, ranging only from 1 to 4. With such little accuracy, discrepancies are guaranteed. This inaccuracy is exacerbated by the fact that body temperature is inaccurately measured on the surface. External temperature is often swayed by outside sources of heat, while internal temperature can be more accurately measured through oral or rectal exams, such as the mouth thermometer used as the gold standard in this experiment. The Spree exam, in order to improve accuracy in measuring temperature, should adopt a more detailed scale than the current 1-4 scale. Also, to improve accuracy, making the device more compact and able to fit within the mouth would allow for more accurate readings. However, this would inconvenience the user, so another method may be necessary. However, the current level of uncertainty is unacceptable in a final product.

As for errors in heart rate measurements, there was no significant difference between the pulse ox and the Spree device. However, measurements were sporadic, with the device often unavailable when the timer sounded. As a result, there is enormous room for inaccuracies due to uneven measuring intervals, which could result in understating high heart rate measurements or overstating low heart rate measurements. This would also undermine consumer utility; if the device itself is unable to establish a connection when it is needed, much of its usefulness is diminished. In order to address this, the technology itself must be improved. The application should be able to maintain a consistent connection with any nearby device and display constant measurements. In this way, while measurements may be accurate to a certain degree compared to the gold standard, they will also be consistent and readily available.

Finally, the physical design of the device itself was clunky and inconvenient. The test subject often readjusted the device, feeling uncomfortable due to the lack of a size-adjusting strap. Also, matted hair would block the device itself, causing discrepancy in the data. Positioning of the band would influence the readings and the reception to the application. All of these are disadvantages of using a headband as the final product. In order to create a more practical design, placement in a less conspicuous location may be in order, such as the wrist or around the waist.

Altogether, the Spree monitoring device possesses many design errors and provides inaccurate measurements. A reform of the design is necessary, and will be the only way that a convenient, pragmatic, and effective device can be manufactured.


Target Population and Need

The target population of the Strush toothbrush is anyone with health conditions that can be exacerbated by stress. Those with cardiovascular issues or high blood pressure would benefit from the use of this product. In addition, asthmatics whose asthma can be triggered by stress would benefit from knowing how high their stress levels are. In general, anyone with health conditions that can be affected by stress levels would benefit from being able to accurately measure their stress levels because there is no easy method for the average patient to do so in their own home. This type of device is needed in order to help monitor those with potentially fatal health problems related to stress. Many patients are constantly at risk of reoccurring health problems that result from stress. Although brushing teeth only occurs several times during the day, the device can be used at any time, because saliva is the only needed substance to measure cortisol levels. By simply placing the head of the toothbrush on the tongue, cortisol levels can be determined.

Research articles that helped determine possibility of salivary cortisol measurement.

Device Design

The device is an electric toothbrush that has been modified to include a sensor that detects cortisol levels in saliva. These levels would be displayed on an LED monitor located on the front face of the toothbrush handle. Furthermore, we are including a rubber stress grip to help relieve the stress of individuals who have consistently high cortisol levels. Also, at the bottom of the toothbrush is a bluetooth speaker, which can play calming music by simply synching to the phone of the user. In doing so, the device can not only monitor, but also mitigate stress symptoms.


Dataset and Statistics

2014-10-14 22 44 59-.png 2014-10-14 22 45 35-.png 2014-10-14 22 45 57-.png

Gold Standard Morning: Mean - 19.78571429, Standard Deviation - 2.9902307950, Standard Error - .32822047

Strush Morning: Mean - 19.82142857, Standard Deviation - 3.311756038, Standard Error - 0.363512451

Gold Standard Afternoon: Mean - 6.202380952, Standard Deviation - 2.619573045, Standard Error - 0.287535497

Strush Afternoon: Mean - 6.416666667, Standard Deviation - 3.189622984, Standard Error - 0.350106606

Gold Standard Night: Mean - 3.369047619, Standard Deviation - 1.588966186, Standard Error - 0.174411698

Strush Night: Mean - 3.904761905, Standard Deviation - 1.942666455, Standard Error - 0.213235346


Morning T-Test: 0.9416086

Afternoon T-Test: 0.634821844

Night T-Test: 0.052102711

Overall T-Test: 0.698218419

Pearson's R Correlation: 0.984092502



Morning T-Test was 0.9416086, which is greater than .05, so there is no statistically significant difference between the gold standard and Strush.

Afternoon T-Test was 0.634821844, which is greater than .05, so there is no statistically significant difference between the gold standard and Strush.

Evening T-Test was 0.052102711, which is greater than .05, so there is no statistically significant difference between the gold standard and Strush.