function t = updateCheck(filename)
d = dir(filename);
lastdate = d.date;
dt = 2;

t = timer('TimerFcn',{@checkFile, filename, lastdate}, 'Period', dt, ...
    'ExecutionMode', 'FixedDelay');
start(t)

function checkFile(t, foo2, filename, lastdate) %#ok<INUSL>
d = dir(filename);
if ~strcmp(d.date, lastdate)
    disp('File was updated')
    % Process for processing new file goes here
end
set(t, 'TimerFcn',{@checkFile, filename, d.date}) % set new modification date