pyActigraphy.sleep.ScoringMixin.SleepRegularityIndex

ScoringMixin.SleepRegularityIndex(freq='15min', bin_threshold=None, algo='Roenneberg', *args, **kwargs)

Sleep regularity index

Likelihood that any two time-points (epoch-by-epoch) 24 hours apart are in the same sleep/wake state, across all days. This index is originally defined in [1] and validated in older adults in [2].

Parameters

• freq (str, optional) – Resampling frequency. Default is ‘15min’

• bin_threshold (bool, optional) – If bin_threshold is not set to None, scoring data above this threshold are set to 1 and to 0 otherwise. Default is None.

• algo (str, optional) – Sleep scoring algorithm to use. Default is ‘Roenneberg’.

• *args – Variable length argument list passed to the scoring algorithm.

• **kwargs – Arbitrary keyword arguements passed to the scoring algorithm.

Returns

sri

Return type

float

Notes

The sleep regularity index (SRI) is defined as:

\[SRI = -100 + \frac{200}{M(N-1)} \sum_{j=1}^M\sum_{i=1}^N \delta(s_{i,j}, s_{i+1,j})\]

with:

\(\delta(s_{i,j}, s_{i+1,j}) = 1\) if \(s_{i,j} = s_{i+1,j}\) and 0 otherwise.

References

1

Phillips, A. J. K., Clerx, W. M., O’Brien, C. S., Sano, A., Barger, L. K., Picard, R. W., … Czeisler, C. A. (2017). Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing. Scientific Reports, 7(1), 1–13. https://doi.org/10.1038/s41598-017-03171-4

2

Lunsford-Avery, J. R., Engelhard, M. M., Navar, A. M., & Kollins, S. H. (2018). Validation of the Sleep Regularity Index in Older Adults and Associations with Cardiometabolic Risk. Scientific Reports, 8(1), 14158. https://doi.org/10.1038/s41598-018-32402-5

Examples