D. Robles-Camarillo et al. / J. Biomedical Science and Engineering 6 (2013) 1-7 7

Table 5. Linear regression results for VA: Diagnosis type.

Group Linear model

r r2 StdError

RP VA = 0.0038 t + 0.4919 0.8915 0.9442 0.0251

Usher I VA = 0.0022 t + 0.2550 0.7602 0.8719 0.0236

Stimulated

Usher II VA = 0.0034 t + 0.5257 0.8384 0.9156 0.0281

RP VA = −0.0012 t + 0.6205 0.4674 0.6837 0.0233

Usher I VA = −0.0007 t + 0.3045 0.5167 0.7188 0.0134

Non stimulated

Usher II VA = −0.0004 t + 0.6053 0.0471 0.2170 0.0331

cient modeled, because their correlation coefficient (r)

and coefficient of determination (r2) are so close to 1

(Table 4), followed by the group of SE of patients be-

tween 31 and 50 years old, with the same characteristics

(Table 3). This means that the variability of measure-

ments (VA) is low enough to describe the statistical

modeled tendency, making the model accurate for statis-

tical validation.

With those estimations it is possible to affirm the

safety of the proposed TES waveform and parameters as

well as a partial effect of recovery and in some cases the

improvement of VA characteristics. It is more challenging

to prove the efficacy of treatment and establish methods

of comparison between similar treatments [3] in a disease

such as RP, due to the natural course of disease pro-

gression in these patients, it can be highly variable [3].

We acknowledge that our trial is small and most results

are not statistically significant, but in further proposed

protocols we will consider correcting the statistical va-

lidation.

5. ACKNOWLEDGEMENTS

The authors thank Prof. Domenica Petulla (Culver Academies, IN,

USA), for her writing assistance, to Consejo Nacional de Ciencia y

Tecnología (CONACyT, México), the Universidad Politécnica de Pa-

chuca (UPP, México), the Instituto Politécnico Nacional (IPN, México)

and “Hospital Dr. Luis Sánches Búlnes” (APEC, México) for their

support in this research.

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