Affiliations: Department of Psychology, University of New Mexico,
Albuquerque, NM, USA | Department of Neurosciences, University of New Mexico,
Albuquerque, NM, USA
Note: [] Corresponding author: Dennis M. Feeney, Ph.D., The Department of
Psychology, The University of New Mexico, Albuquerque, NM 87131-1161, USA.
Tel.: +1 505 277 7751; Fax: +1 505 277 1394; E-mail: [email protected]
Abstract: This review presents data from laboratory studies and clinical
trials indicating the efficacy of the "Noradrenergic Strategy" for enhancing
recovery after cortical injury. Short-term acute treatment combining Physical
Therapy (PT) with drugs increasing noradrenaline (NA) levels enhances recovery
of hemiplegia in both laboratory studies and clinical trials which also report
improved aphasia recovery. Importantly these effects endure even when treatment
is initiated months after stroke onset. The hypothesized mechanisms included
modulation of neuronal processes underlying "spontaneous" recovery since
drugs reducing NA levels slow spontaneous recovery. The effect of some drugs
change with time after sensorimotor cortex (SMCx) injury. Drugs reducing NA
levels, including clonidine and prazosin, and GABA receptor agonists at doses
having little effect early after injury, when administered to animals or stroke
patients after "complete recovery" transiently reinstate the original
symptoms. Reinstatement by prazosin remains unchanged after repeated testing
for over six months in rat, and the deficits can be as severe as the first days
after injury. This suggests "completed" recovery is an inaccurate label for
an enduring "fragile" state. This transient reinstatement of symptoms may be
useful for distinguishing causal from corollary relationships between symptoms
and physiological processes proposed as mechanisms for recovery of
function.
Keywords: noradrenaline, norepinephrine, recovery of function, rehabilitation, brain injury, diaschisis
