p.measures: Calculate grand average and individual peak amplitude and...

Description Usage Arguments Value Author(s) Examples

View source: R/Peaks.R

Description

p.measures calculates local or simple peak amplitude and latency for each condition in the data frame. Values are calculated for grand average waveforms, as well as for each individual subject. Values are based on the electrode, or electrode cluster for dense arrays, provided in electrodes.

Usage

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p.measures(data, electrodes, window, num.pts = 10, pol = "abs")

Arguments

data

A data frame in the format returned from load.data

electrodes

A single value or concatenation of several values (to be averaged) indicating which electrodes to include in generating the plot. At this time, if the raw data files imported using load.data) do not have a header, you must include a capital "V" in front of the number and enclose each electrode in quotes. (For example, electrodes = "V78", or electrodes = c("V78", "V76").)

window

The beginning and end points of a time window of interest; this is different from the beginning and ending times epoch.st and epoch.end defined in load.data (you only need to define the epoch once upon importing the data).

num.pts

The number of bins to check for local peak measures. If no local peaks are found, the simple peak will be returned. To force the simple peak, set num.pts to 0.

pol

The polarity of peaks to favor when multiple peaks are present. Entering "pos" will locate the most positive peak. Entering "neg" will locate the most negative peak. Entering "abs" will find the greatest deviation from 0, regardless of the polarity (i.e., the absolute value). If a single peak is located, it will be selected regardless of polarity specified. To avoid this, set num.pts to 0 (for simple peak measures).

Value

A data frame with columns labeled:

A plot indicating the time window and identified peak(s)

Author(s)

Travis Moore

Examples

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# Calculate peak latency and amplitude
p.measures(ERPdata, electrodes = "V78", window = c(1000, 1500), num.pts=10, pol="abs")

erp.easy documentation built on May 29, 2017, 11:39 p.m.