  We perform a detailed study of the stellar populations in a sample of massive
Fornax dwarf galaxies using a set of newly defined line indices. Using data
from the Integral field spectroscopic data, we study abundance ratios of eight
dEs with stellar mass ranging from 10$^8$ to 10$^{9.5}$ M$_\odot$ in the Fornax
cluster. We present the definitions of a new set of high-resolution Lick-style
indices to be used for stellar population studies of unresolved small stellar
systems. We identify 23 absorption features and continuum regions, mainly
dominated by 12 elements (Na, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Y, Ba and Nd) in
the wavelength range 4700 - 5400 \r{A} and characterise them as a function of
age, metallicity and alpha element abundance ratios. We analyse eight dEs and
interpret the line strengths, measured in our new high resolution system of
indices, with the aid of stellar population models with high enough spectral
resolution. We obtain abundance ratio proxies for a number of elements that
have never been studied before for dwarf ellipticals outside the Local Group.
These proxies represent relative deviations from predicted index-strengths of
base stellar population models built-up following the abundance pattern of The
Galaxy. The abundance proxy trend results are compared to abundance ratios from
resolved stars in the Local Group, and indices from integrated light of larger
early-type galaxies. We find that all our dwarfs show a pattern of abundance
ratios consistent with the disk of the Milky Way, indicative of slow formation
in comparison to their high mass counterparts.
