Detect secondary sleep periods (naps) using the Crespo algorithm

Identifies naps — secondary sleep periods — in an actigraphy recording using the nap variant of the Crespo algorithm. This function should be run after detect_sleep_crespo().

Usage

detect_naps_crespo(
  x,
  epoch_h = NULL,
  median_filter_h = 8,
  pad_h = 1,
  nap_median_thr = 2,
  nap_zero_prop_thr = 0.5,
  nap_zero_prop_hws = 5L,
  use_and = FALSE
)

Arguments

x: A tibble as returned by detect_offwrist_bimodal() (or prepare_actigraphy() if off-wrist detection is skipped), containing columns datetime, activity, and state.
epoch_h: numeric(1). Number of epochs per hour. If NULL (default), estimated automatically from the median inter-epoch interval in datetime.
median_filter_h: numeric(1). Length of the preprocessing median filter window in hours. Default is 8.
pad_h: numeric(1). Padding length in hours added before the adaptive median filter. Default is 1.
nap_median_thr: numeric(1). Epochs with a rolling median activity below this value may be scored as nap sleep. Default is 2.0.
nap_zero_prop_thr: numeric(1). Epochs with a rolling zero-activity proportion above this threshold may be scored as nap sleep. Default is 0.5.
nap_zero_prop_hws: integer(1). Half-window size (epochs) for the rolling zero-proportion filter. Default is 5L.
use_and: logical(1). If TRUE, both the median activity AND zero-proportion criteria must be met. If FALSE (default), either criterion is sufficient.

Value

The input tibble x with state and sleep columns updated. Nap epochs have state == 7 and are merged into sleep as value 1.

Details

The nap algorithm combines two criteria: a low rolling median activity threshold and a high zero-activity proportion around each epoch. Epochs satisfying either (or both, if use_and = TRUE) criteria are scored as nap sleep.

References

Crespo, C., Aboy, M., Fernández, J. R., & Mojón, A. (2012). Automatic identification of activity-rest periods based on actigraphy. Journal of Medical and Biological Engineering, 32(4), 249–256. doi:10.5405/jmbe.1033

Examples

if (FALSE) { # \dontrun{
rec  <- read_acttrust("recordings/P001.txt")
prep <- prepare_actigraphy(rec)
prep <- detect_offwrist_bimodal(prep)
prep <- detect_sleep_crespo(prep)
prep <- detect_naps_crespo(prep)
} # }