**5. Results and discussions**

The IOS data collected from 47 children in 2008 and Model Parameters calculated from them, under pre-bronchodilation and post-bronchodilation conditions were analyzed. The eRIC and aRIC Model Parameters were calculated over the frequency range of 5 to 25 Hz.

Impulse Oscillometric Features and Respiratory System Models Track Small Airway Function in Children 125

Range Mean±SD Range Mean±SD

**IOS Measurements and Model Parameters PSAI Group N=4 Pre-Bronchodilation Post-Bronchodilation** 

**R3** (kPa/l/s) 0.47-0.99 0.67±0.25 **R3** (kPa/l/s) 0.37-0.96 0.60±0.27 **R5**(kPa/l/s) 0.39-0.84 0.57±0.21 **R5**(kPa/l/s) 0.30-0.87 0.50±0.26 **R3-R20**(kPa/l/s) 0.14-0.44 0.30±0.15 **R3-R20**(kPa/l/s) 0.14-0.39 0.26-0.12 **R5-R20**(kPa/l/s) 0.07-0.29 0.19±0.11 **R5-R20**(kPa/l/s) 0.07-0.30 0.17±0.10 **X3**(kPa/l/s) -0.43 -0.28±0.11 **X3**(kPa/l/s) -0.12 -0.24±0.06 **X5**(kPa/l/s) -0.18 -0.22±0.09 **X5**(kPa/l/s) -0.11 -0.17±0.05 **AX** (kPa/l) 0.57-2.57 1.31±0.95 **AX** (kPa/l) 0.43-2.20 1.11±0.82 **Fres** (1/s) 15.53-17.36 16.44±0.92 **Fres** (1/s) 12.47-17.19 15.37±2.54 **eRIC Cp** (l/kPa) 0.0445-0.1616 0.0963±0.0556 **eRIC Cp** (l/kPa) 0.0243-0.1636 0.0978±0.0621 **Rp** (kPa/l/s) 0.4398-0.6730 0.5443±0.1211 **Rp** (kPa/l/s) 0.3539-0.6174 0.4886±0.1180 **aRIC Cp** (l/kPa) 0.0389-0.1616 0.0858±0.0572 **aRIC Cp** (l/kPa) 0.0077-0.1636 0.0861±0.0690 **Rp** (kPa/l/s) 0.3561-0.6730 0.5116±0.1403 **Rp** (kPa/l/s) 0.3539-0.8784 0.5339±0.2423

> **IOS Measurements and Model Parameters SAI Group N=11 Pre-Bronchodilation Post-Bronchodilation**

**R3** (kPa/l/s) 0.55-0.91 0.73±0.12 **R3** (kPa/l/s) 0.50-0.92 0.67±0.14 **R5**(kPa/l/s) 0.46-0.72 0.61±0.09 **R5**(kPa/l/s) 0.43-0.78 0.57±0.12 **R3-R20**(kPa/l/s) 0.25-0.57 0.38±0.10 **R3-R20**(kPa/l/s) 0.16-0.51 0.30±0.10 **R5-R20**(kPa/l/s) 0.17-0.38 0.26±0.06 **R5-R20**(kPa/l/s) 0.07-0.37 0.20±0.08 **X3**(kPa/l/s) -0.32 -0.32±0.11 **X3**(kPa/l/s) -0.27 -0.26±0.08 **X5**(kPa/l/s) -0.27 -0.25±0.09 **X5**(kPa/l/s) -0.2 -0.20±0.07 **AX** (kPa/l) 1.10-2.73 1.87±0.52 **AX** (kPa/l) 0.54-2.61 1.36±0.59 **Fres** (1/s) 17.37-23.15 19.47±1.95 **Fres** (1/s) 16.8-23.41 19.44±2.26 **eRIC Cp** (l/kPa) 0.0356-0.0710 0.0533±0.0105 **eRIC Cp** (l/kPa) 0.0358-0.1485 0.0733±0.0291 **Rp** (kPa/l/s) 0.3126-0.9167 0.5885±0.1990 **Rp** (kPa/l/s) 0.3082-0.8075 0.5023±0.1651 **aRIC Cp** (l/kPa) 0.0150-0.1007 0.0409±0.0230 **aRIC Cp** (l/kPa) 0.0185-0.1485 0.0485±0.0404 Rp (kPa/l/s) 0.3486-0.7291 0.4992±0.1100 Rp (kPa/l/s) 0.3243-0.5810 0.4359±0.0982

Range Mean±SD Range Mean±SD

**Table 8.** PSAI children IOS and Model Parameters Pre- and Post-B (N=4)

**Table 9.** SAI children IOS and Models Parameter Pre- and Post-B (N=11)

The IOS and Model Parameters selected for analysis were selected from our previous publications as they produced significant results to differentiate between Healthy and Impaired as well as, between Pre- and Post- bronchodilation conditions. These parameters were chosen due to their ability to evaluate respiratory system's properties and impairments. The IOS, eRIC and aRIC Model Parameters analyzed were: R3, R5, R3-R20, R5- R20, X3, X5, AX, Fres, eRIC Cp, eRIC Rp, aRIC Cp and aRIC Rp. In addition to our previous published results, we included IOS parameters at 3 Hz (R3, X3, R3-R20) to our analysis here to evaluate their performance.

After quality assurance by our expert clinician, the collected IOS data from all 47 children were classified into four groups: 6 Healthy (or Normal), 4 PSAI, 11 definite SAI and 24 Asthmatics. Children in these four groups were either Anglo or Hispanic based upon their parent's declarations in the questionnaires.

Mean ± standard deviation and range values (Pre- and Post-B data collected in 2008) for each IOS and Model Parameters analyzed are presented in Table 7 for Healthy children, in Table 8 for PSAI children, in Table 9 for children with SAI, and in Table 10 for those with Asthma.


**Table 7.** Healthy children IOS and Model Parameters Pre- and Post-B (N=6)



**5. Results and discussions** 

to evaluate their performance.

parent's declarations in the questionnaires.

The IOS data collected from 47 children in 2008 and Model Parameters calculated from them, under pre-bronchodilation and post-bronchodilation conditions were analyzed. The eRIC and aRIC Model Parameters were calculated over the frequency range of 5 to 25 Hz.

The IOS and Model Parameters selected for analysis were selected from our previous publications as they produced significant results to differentiate between Healthy and Impaired as well as, between Pre- and Post- bronchodilation conditions. These parameters were chosen due to their ability to evaluate respiratory system's properties and impairments. The IOS, eRIC and aRIC Model Parameters analyzed were: R3, R5, R3-R20, R5- R20, X3, X5, AX, Fres, eRIC Cp, eRIC Rp, aRIC Cp and aRIC Rp. In addition to our previous published results, we included IOS parameters at 3 Hz (R3, X3, R3-R20) to our analysis here

After quality assurance by our expert clinician, the collected IOS data from all 47 children were classified into four groups: 6 Healthy (or Normal), 4 PSAI, 11 definite SAI and 24 Asthmatics. Children in these four groups were either Anglo or Hispanic based upon their

Mean ± standard deviation and range values (Pre- and Post-B data collected in 2008) for each IOS and Model Parameters analyzed are presented in Table 7 for Healthy children, in Table 8 for PSAI children, in Table 9 for children with SAI, and in Table 10 for those with Asthma.

> **IOS Measurements and Model Parameters Healthy Group N=6 Pre-Bronchodilation Post-Bronchodilation**

**R3** (kPa/l/s) 0.34-0.59 0.41±0.09 **R3** (kPa/l/s) 0.30-0.54 0.38±0.08 **R5**(kPa/l/s) 0.29-0.51 0.35±0.08 **R5**(kPa/l/s) 0.25-0.48 0.33±0.08 **R3-R20**(kPa/l/s) 0.05-0.12 0.09±0.02 **R3-R20**(kPa/l/s) 0.03-0.13 0.08±0.04 **R5-R20**(kPa/l/s) -0.08 0.03±0.03 **R5-R20**(kPa/l/s) -0.1 0.03±0.04 **X3**(kPa/l/s) -0.12 -0.16±0.05 **X3**(kPa/l/s) -0.13 -0.15±0.05 **X5**(kPa/l/s) -0.06 -0.10±0.02 **X5**(kPa/l/s) -0.05 -0.10±0.02 **AX** (kPa/l) 0.18-0.36 0.26±0.06 **AX** (kPa/l) 0.16-0.36 0.24±0.07 **Fres** (1/s) 10.26-13.46 11.18±1.15 **Fres** (1/s) 9.6-13.74 10.99±1.76 **eRIC Cp** (l/kPa) 0.2073-0.2816 0.2346±0.0284 **eRIC Cp** (l/kPa) 0.1894-0.2892 0.2297±0.0362 **Rp** (kPa/l/s) 0.2163-0.8016 0.5665±0.2788 **Rp** (kPa/l/s) 0.2227-0.5801 0.3501±0.1630 **aRIC Cp** (l/kPa) 0.1851-0.2331 0.2091±0.0169 **aRIC Cp** (l/kPa) 0.1436-0.2411 0.2087±0.0366 **Rp** (kPa/l/s) 0.1891-0.7206 0.3922±0.2057 **Rp** (kPa/l/s) 0.1992-0.6173 0.3151±0.1710

**Table 7.** Healthy children IOS and Model Parameters Pre- and Post-B (N=6)

Range Mean±SD Range Mean±SD


**Table 9.** SAI children IOS and Models Parameter Pre- and Post-B (N=11)


Impulse Oscillometric Features and Respiratory System Models Track Small Airway Function in Children 127

Figures 5, 6, 7, 8, 9, 10 and 11 show in a more graphical fashion the changes in the most

significant IOS and Model Parameters mean values for each of the four groups.

**Figure 5.** R3 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B

**Figure 6.** R5 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B

**Figure 7.** R3-R20 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B

conditions.

conditions.

conditions.

**Table 10.** Asthmatic children IOS and Model Parameters Pre- and Post-B (N=24)

With the tabulation of IOS and Model Parameters we achieved one of the goals of this research, to present baseline (Pre-) and Post-bronchodilation IOS parameters in Anglo and Hispanic children, classified in four groups: Healthy (table 7), Probable Small Airway Impairment (PSAI) (table 8), Small Airway Impairment (SAI) (table 9) and Asthma (table 10).

As expected, in the Healthy group (table 7), comparing Pre- and Post-bronchodilation IOS and Model Parameters mean values, there are almost no differences between Pre- and Postbronchodilation measurements. In table 8, for the PSAI group we observe a modest difference between the mean IOS and Model Parameters during the Pre and Postbronchodilation conditions. In contrast, in tables 9 and 10 we observe a noticeably bigger difference between the IOS and Model Parameters mean values, comparing Pre and Postbronchodilation conditions. Also as expected, the biggest difference between Pre- and Postbronchodilation conditions exists (table 10), in the Asthmatic children group, for all the IOS and Model Parameters mean values.

Our expert clinician confirmed that the range of values of all analyzed features: R3, R5, R3- R20, R5-R20, X3, X5, AX, Fres, eRIC Cp, eRIC Rp, aRIC Cp and aRIC Rp obtained for the SAD and Asthmatic groups were comparable to those values he has observed over many years in other asthmatic children of the same age range. Going to increasingly abnormal levels of "diagnostic classification," R3, R5, R5-R20, AX, Fres and Rp continue to increase from Normal to PSAI to SAI to Asthma, while X3, X5 and Cp decreased in this progression.

Figures 5, 6, 7, 8, 9, 10 and 11 show in a more graphical fashion the changes in the most significant IOS and Model Parameters mean values for each of the four groups.

126 Practical Applications in Biomedical Engineering

(table 10).

and Model Parameters mean values.

**IOS Measurements and Model Parameters Asthma Group N=24 Pre-Bronchodilation Post-Bronchodilation** 

**R3** (kPa/l/s) 0.45-1.77 0.82±0.26 **R3** (kPa/l/s) 0.37-1.31 0.62±0.20 **R5**(kPa/l/s) 0.39-1.28 0.68±0.19 **R5**(kPa/l/s) 0.32-1.04 0.52±0.16 **R3-R20**(kPa/l/s) 0.14-1.24 0.44±0.22 **R3-R20**(kPa/l/s) 0.10-0.78 0.30±0.14 **R5-R20**(kPa/l/s) 0.07-0.75 0.30±0.14 **R5-R20**(kPa/l/s) 0.05-0.52 0.20±0.10 **X3**(kPa/l/s) -0.74 -0.34±0.15 **X3**(kPa/l/s) -0.55 -0.27±0.13 **X5**(kPa/l/s) -0.69 -0.29±0.14 **X5**(kPa/l/s) -0.47 -0.21±0.11 **AX** (kPa/l) 0.45-6.61 2.24±1.23 **AX** (kPa/l) 0.28-4.35 1.38±0.90 **Fres** (1/s) 14.44-24.19 19.48±2.64 **Fres** (1/s) 12.76-20.86 17.68±2.35 **eRIC Cp** (l/kPa) 0.0200-0.1782 0.0593±0.0347 **eRIC Cp** (l/kPa) 0.0047-0.2466 0.0848±0.0527 **Rp** (kPa/l/s) 0.2925-1.8113 0.6749±0.2949 **Rp** (kPa/l/s) 0.2318-1.2561 0.5050±0.2148 **aRIC Cp** (l/kPa) 0.0148-0.1522 0.0570±0.0390 **aRIC Cp** (l/kPa) 0.0047-0.2087 0.0776±0.0519 **Rp** (kPa/l/s) 0.2250-1.6536 0.5840±0.2848 **Rp** (kPa/l/s) 0.1604-1.1443 0.4288±0.2033

With the tabulation of IOS and Model Parameters we achieved one of the goals of this research, to present baseline (Pre-) and Post-bronchodilation IOS parameters in Anglo and Hispanic children, classified in four groups: Healthy (table 7), Probable Small Airway Impairment (PSAI) (table 8), Small Airway Impairment (SAI) (table 9) and Asthma

As expected, in the Healthy group (table 7), comparing Pre- and Post-bronchodilation IOS and Model Parameters mean values, there are almost no differences between Pre- and Postbronchodilation measurements. In table 8, for the PSAI group we observe a modest difference between the mean IOS and Model Parameters during the Pre and Postbronchodilation conditions. In contrast, in tables 9 and 10 we observe a noticeably bigger difference between the IOS and Model Parameters mean values, comparing Pre and Postbronchodilation conditions. Also as expected, the biggest difference between Pre- and Postbronchodilation conditions exists (table 10), in the Asthmatic children group, for all the IOS

Our expert clinician confirmed that the range of values of all analyzed features: R3, R5, R3- R20, R5-R20, X3, X5, AX, Fres, eRIC Cp, eRIC Rp, aRIC Cp and aRIC Rp obtained for the SAD and Asthmatic groups were comparable to those values he has observed over many years in other asthmatic children of the same age range. Going to increasingly abnormal levels of "diagnostic classification," R3, R5, R5-R20, AX, Fres and Rp continue to increase from Normal to PSAI to SAI to Asthma, while X3, X5 and Cp decreased in this progression.

**Table 10.** Asthmatic children IOS and Model Parameters Pre- and Post-B (N=24)

Range Mean±SD Range Mean±SD

**Figure 5.** R3 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B conditions.

**Figure 6.** R5 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B conditions.

**Figure 7.** R3-R20 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B conditions.

Impulse Oscillometric Features and Respiratory System Models Track Small Airway Function in Children 129

**Figure 11.** aRIC Cp mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B

Similarities between Normal and PSAI groups and between SAI and Asthmatic groups were

From tables 7,8,9, and10 and figures 7,8,9, 10 and 11 we can observe that the most significant IOS and Model Parameters for children classified as Healthy or PSAI were comparable, as these parameters showed a modest difference between these groups. However, these same parameters exhibited clear increases in R3, R5, R3-R20, R5-R20, AX, Fres, and Rp, and a clear decrease in X3, X5 and Cp going from Normal to PSAI. Going to increasingly abnormal levels of "diagnostic classification," R5, R5-R20, AX, Fres and Rp continue to increase from Healthy to PSAI to SAI to Asthmatic conditions, while X5 and Cp decrease in this

In the statistical analysis performed for this research comparing Pre- and Post-B IOS and eRIC and aRIC Model Parameters in the Normal or Healthy group, no significant

Healthy (Normal) Group

Comparing Pre- and Post-B IOS and eRIC and aRIC Model Parameters for the PSAI group

Comparing Pre- and Post-B IOS and eRIC and aRIC Model Parameters for the SAI group the following parameters showed significant differences: R3,R5,X3,X5,X10,X15,R3-R20,R5-

**All IOS and Model** Parameters >0.05

only R3, R35 and eRIC Rc showed significant differences (see Table 12.)

R20,AX,aRIC Rp, eRIC Rp, eRIC I and eRIC Cp (see Table 13).

**Pre-B vs Post-B p values** 

progression. Differences between SAI and Asthmatic children were also modest.

conditions.

also observed.

differences were observed (see Table 11).

**Table 11.** Healthy group p values.

**Figure 8.** R5-R20 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B conditions.

**Figure 9.** AX mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B conditions.

**Figure 10.** eRIC Cp mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B conditions.

**Figure 11.** aRIC Cp mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B conditions.

Similarities between Normal and PSAI groups and between SAI and Asthmatic groups were also observed.

From tables 7,8,9, and10 and figures 7,8,9, 10 and 11 we can observe that the most significant IOS and Model Parameters for children classified as Healthy or PSAI were comparable, as these parameters showed a modest difference between these groups. However, these same parameters exhibited clear increases in R3, R5, R3-R20, R5-R20, AX, Fres, and Rp, and a clear decrease in X3, X5 and Cp going from Normal to PSAI. Going to increasingly abnormal levels of "diagnostic classification," R5, R5-R20, AX, Fres and Rp continue to increase from Healthy to PSAI to SAI to Asthmatic conditions, while X5 and Cp decrease in this progression. Differences between SAI and Asthmatic children were also modest.

In the statistical analysis performed for this research comparing Pre- and Post-B IOS and eRIC and aRIC Model Parameters in the Normal or Healthy group, no significant differences were observed (see Table 11).


**Table 11.** Healthy group p values.

128 Practical Applications in Biomedical Engineering

conditions.

conditions.

conditions.

**Figure 8.** R5-R20 mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B

**Figure 9.** AX mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B

**Figure 10.** eRIC Cp mean values for the H, PSAI, SAI and Asthmatic children under Pre- and Post-B

Comparing Pre- and Post-B IOS and eRIC and aRIC Model Parameters for the PSAI group only R3, R35 and eRIC Rc showed significant differences (see Table 12.)

Comparing Pre- and Post-B IOS and eRIC and aRIC Model Parameters for the SAI group the following parameters showed significant differences: R3,R5,X3,X5,X10,X15,R3-R20,R5- R20,AX,aRIC Rp, eRIC Rp, eRIC I and eRIC Cp (see Table 13).


Impulse Oscillometric Features and Respiratory System Models Track Small Airway Function in Children 131

**Pre-B vs Post-B p value** 

Post-B, only Fres showed a significant difference. Finally comparing SAI Pre-B vs Asthma

**Asthmatic Group** 

**R3** (kPa/l/s) <1.5E-9 **R5** (kPa/l/s) <1.6E-10 **R10** (kPa/l/s) <9.7E-08 **R15** (kPa/l/s) <0.0002 **R20** (kPa/l/s) <0.0002 **R25** (kPa/l/s) <3.9E-07 **R35** (kPa/l/s) <1.7E-06 **X3** (kPa/l/s) <0.005 **X5** (kPa/l/s) <0.002 **X10** (kPa/l/s) <0.0003 **X15** (kPa/l/s) <1.4E-6 **X20** (kPa/l/s) <0.0002 **X25** (kPa/l/s) <0.01 **X35** (kPa/l/s) <0.003 **R3-R20** (kPa/l/s) <5.6E-06 **R5-R20** (kPa/l/s) <2.5E-06 **AX** (kPa/l/s) <3.1E-08 **Fres** (1/s) <0.0002

**aRIC Rc** (kPa/l/s) <0.006

**eRIC Rc** (kPa/l/s) <0.002 **Rp** (kPa/l/s) <4.5E-06 **Cp** (l/kPa) <0.0003

**Table 14.** Asthmatic group p values

**Rp** (kPa/l/s) <4.5E-07 **I** (kPa/l/s2) <0.002 **Cp** (l/kPa) <0.0003

Pre-B, and SAI Post-B vs Asthma Post-B, no significant differences were found.

**Table 12.** PSAI group p values.


**Table 13.** SAI group p values

Comparing Pre- and Post-B IOS, eRIC and aRIC Model Parameters for the Asthmatic group all of the parameters showed significant differences with the exception of aRIC Ce and eRIC I (see Table 14).

Significant differences between these groups in the aforementioned IOS and Model Parameters were found. Comparing Normal Pre-B to PSAI Pre-B, all of the IOS and Model Parameters showed significant differences, with the exception of aRIC Rp and eRIC Rp. Comparing Normal (Healthy) Post-B and PSAI Post-B, the majority of the parameters showed significant differences with the exception of R3, R5, eRIC Rp and aRIC Rp. Comparing PSAI Pre-B and SAI Pre-B data, only three parameters showed significant differences between these groups: Fres, eRIC Cp and aRIC Cp. For PSAI Post-B and SAI Post-B, only Fres showed a significant difference. Finally comparing SAI Pre-B vs Asthma Pre-B, and SAI Post-B vs Asthma Post-B, no significant differences were found.


**Table 14.** Asthmatic group p values

130 Practical Applications in Biomedical Engineering

**Table 12.** PSAI group p values.

**Table 13.** SAI group p values

I (see Table 14).

**PSAI Group** 

**R3** (kPa/l/s) <0.05 **R35** (kPa/l/s) <0.03 **eRIC Rc** (kPa/l/s) <0.04

**SAI Group** 

**R3** (kPa/l/s) <0.02 **R5** (kPa/l/s) <0.05 **X3** (kPa/l/s) <0.02 **X5** (kPa/l/s) <0.005 **X10** (kPa/l/s) <0.001 **X15** (kPa/l/s) <0.005 **R3-R20** (kPa/l/s) <0.001 **R5-R20** (kPa/l/s) <0.005 **AX** (kPa/l/s) <0.0002 **aRIC Rp** (kPa/l/s) <0.01 **eRIC Rp** (kPa/l/s) <0.02 **I**(kPa/l/s2) <0.05 **Cp** (l/kPa) <0.03

Comparing Pre- and Post-B IOS, eRIC and aRIC Model Parameters for the Asthmatic group all of the parameters showed significant differences with the exception of aRIC Ce and eRIC

Significant differences between these groups in the aforementioned IOS and Model Parameters were found. Comparing Normal Pre-B to PSAI Pre-B, all of the IOS and Model Parameters showed significant differences, with the exception of aRIC Rp and eRIC Rp. Comparing Normal (Healthy) Post-B and PSAI Post-B, the majority of the parameters showed significant differences with the exception of R3, R5, eRIC Rp and aRIC Rp. Comparing PSAI Pre-B and SAI Pre-B data, only three parameters showed significant differences between these groups: Fres, eRIC Cp and aRIC Cp. For PSAI Post-B and SAI

**Pre-B vs Post-B p values**

**Pre-B vs Post-B p value** 

*These selected parameters seem to be sensitive and reliable indices of lung function for respiratory disease classification using Impulse Oscillometric data, eRIC and aRIC Model Parameters.* 

Impulse Oscillometric Features and Respiratory System Models Track Small Airway Function in Children 133

The statistical correlation between AX and both models' Cps, and R3-R20 and R5-R20 with both models' Rps were also evaluated. The best correlation observed was between AX and eRIC Cp with a value of r = 0.909. The correlation between AX and aRIC Cp had a lower r value equal to 0.760. For the correlation between R3-R20 and eRIC Rp, r was equal to 0.589. The correlation between R5-R20 and eRIC Rp was r = 0.516. For R3-R20 and aRIC Rp, r = 0.787. And finally the correlation between R5-R20 and aRIC Rp was r = 0.731. Figure 12 illustrates the best correlation observed. This was between AX and eRIC Cp.

While expert clinician diagnostic classification distinguished between children based on 4 levels of perceived normality or absence thereof of the visual patterns of IOS data, with the essential features characterizing the differences being associated with abnormalities group mean IOS and the aRIC model data appear to fall into two distinctly different groups: either Normal or Asthmatic, with the essential features characterizing the differences being

Our present and previous studies (52-61, 75), have demonstrated that equivalent electrical circuit Model Parameters of the human respiratory system are able to track changes in the respiratory system function after bronchodilation. Both the eRIC and aRIC models clearly distinguished between children who were Normal (Healthy) or possibly had mild SAI, who showed no significant changes with bronchodilation-BD), and those who were Asthmatic with SAI, both at baseline and at Pre- to Post-BD conditions. The eRIC model showed an apparently larger peripheral airway compliance (Cp) than the aRIC model, probably because it might include some of the "extrathoracic airway compliance" (Ce). On the other hand, the eRIC model is more parsimonious, and the parameter, Ce, that may be difficult for physicians to understand, appears to show no significant change Post-BD in the Asthmatic

It can be observed that children classified as Normal (Healthy) or possible SAI were relatively similar in both IOS and the aRIC model parameters. However, they showed clear increases in R3, R5, R3-R20, R5-R20, AX, Fres, and Rp, and a clear decrease in X3, X5 and Cp

Going to increasingly abnormal levels of "diagnostic classification," R3, R5, R5-R20, AX, Fres and Rp continue to increase from Healthy to PSAI to SAI to Asthma, while X3, X5 and Cp decrease in this progression. Differences between SAI and Asthmatic children

The features used in this work seem to be sensitive and reliable indices for automatic respiratory disease classification using Impulse Oscillometry data. The correlation between

Our expert clinician confirmed that the range of values of all analyzed features: R3, R5, R3- R20, R5-R20, X3, X5, AX, Fres, eRIC Cp, eRIC Rp, aRIC Cp and aRIC Rp obtained for the

AX and the eRIC Cp was the best correlation in both Pre-B and Post-B work.

**6. Conclusions** 

group.

were modest.

going from Normal to PSAI.

associated with abnormalities of peripheral airways.

The correlation coefficient (r) between children Heights and these IOS and Model Parameters was also analyzed. The parameters showed a good correlation, the best correlation was observed for R5 with R = 0.764, and the lowest r value (0.542) was observed for X5. In Table 15 the values for these correlations are presented.


**Table 15.** Correlation coefficients (r) between Height and IOS and respiratory system Model Parameters for 2008 data.

**Figure 12.** Correlation between AX and eRIC Cp for Pre- and Post-B data.

The statistical correlation between AX and both models' Cps, and R3-R20 and R5-R20 with both models' Rps were also evaluated. The best correlation observed was between AX and eRIC Cp with a value of r = 0.909. The correlation between AX and aRIC Cp had a lower r value equal to 0.760. For the correlation between R3-R20 and eRIC Rp, r was equal to 0.589. The correlation between R5-R20 and eRIC Rp was r = 0.516. For R3-R20 and aRIC Rp, r = 0.787. And finally the correlation between R5-R20 and aRIC Rp was r = 0.731. Figure 12 illustrates the best correlation observed. This was between AX and eRIC Cp.
