Description Usage Arguments Details Value Author(s)

View source: R/edge_asymmetry.R

Calculate an *asymmetry index*, a ratio of intra-hemispheric edges in
the left to right hemisphere of a graph for brain MRI data.

1 | ```
edge_asymmetry(g, level = c("hemi", "vertex"))
``` |

`g` |
An |

`level` |
Character string indicating whether to calculate asymmetry for
each region, or the hemisphere as a whole (default: |

The equation is:

*A = \frac{E_{lh} - E_{rh}}{0.5 \times (E_{lh} + E_{rh})}*

where *lh* and *rh* are left and right hemispheres, respectively.
The range of this measure is *[-2, 2]* (although the limits will only be
reached if all edges are in one hemisphere), with negative numbers
indicating more edges in the right hemisphere, and a value of 0 indicating
equal number of edges in each hemisphere.

The `level`

argument specifies whether to calculate asymmetry for each
vertex, or for the whole hemisphere.

A data table with edge counts for both hemispheres and the asymmetry
index; if `level`

is *vertex*, the data table will have
`vcount(g)`

rows.

Christopher G. Watson, [email protected]

brainGraph documentation built on May 29, 2018, 9:03 a.m.

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