1 Erratum to: Med Biol Eng Comput DOI 10.1007/s11517-009-0473-9

Unfortunately, several errors occurred in Sect. 2.3.2 Statistical analysis, second paragraph.

The corrected paragraph is given below.

When considering a parameter X, the variability between the heartbeats of each measurement was evaluated by the intra-registration variability \(\sigma_{h},\) which can be written as follows:

$$ \sigma_{h}=\sqrt{\frac{\sum_{v}\sum_{m}\sum_{b}(X_{v,m,b}- \overline{X}_{v,m})^2}{\sum_{v}\sum_{m}(b_{v,m})-m}} $$
(1)

X v,m,b being the parameter value for the volunteer v, in measurement m at heartbeat b, \(\overline{X}_{v,m}\) the average parameter for measurement m of volunteer v, and, b v,m and m being the number of heart beats of the measurement m for the volunteer v and the total number of measurements, respectively.

The inter-registration variability σ m that evaluates the variability between the measurements of the volunteer can be written as:

$$ \sigma_m=\sqrt{\frac{\sum_{v}\sum_{m}(X_{v,m}- \overline{X}_v)^2}{\sum_{v}(m_v)-v}}. $$
(2)

In this equation, X v,m is the parameter value of measurement m for volunteer v and \(\overline{X}_v\) the average parameter for each volunteer v. The number of measurements for the volunteer v and the number of volunteers are represented by m v and v respectively.