Prospective memory impairment and executive dysfunction in prefrontal lobe damaged patients: is there a causal relationship?
BACKGROUND
The prospective memory (PM) construct is aimed at capturing cognitive operations involved in the successful accomplishment of delayed intentions. It is generally agreed that PM impairment occurs in patients with prefrontal lobes damage.


OBJECTIVE
To evaluate if there is a causal role of a deficit of executive abilities (failures of planning, set-shifting, selective attention, or working memory) over the PM impairment.


METHODS
We report a detailed investigation of PM and executive abilities in two patients with posttraumatic damage to prefrontal lobes who complained from a reduced compliance with appointments and daily routines.


RESULTS
Laboratory tests confirmed a difficulty in fulfilling delayed intentions in response to the occurrence of critical events and elapsed time. In one patient, PM impairment was associated with poor performance on tests investigating planning, working memory, and mental shifting. The other patient performed in the normal range on all executive tests.


CONCLUSIONS
Despite the frequent claim of a dependence of PM deficits from executive dysfunction, the reported cases demonstrate that this is not necessarily the case. The results are discussed in the light of current hypotheses relating PM impairment to other deficits that commonly occur as a result of damage to the prefrontal lobes.
Clinica Neurologica, Università Tor Vergata, Via Orazio Raimondo 18, 00173 Rome, Italy ; Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy.
Giovanni A
GA
Carlesimo
Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy ; Dipartimento di Medicina Clinica, Sanitá Pubblica, Scienze della Vita e dell'Ambiente, Piazzale Salvatore Tommasi 1, L'Aquila, Italy.
Margherita
M
di Paola
Clinica Neurologica, Università Tor Vergata, Via Orazio Raimondo 18, 00173 Rome, Italy ; Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy.
Lucia
L
Fadda
Clinica Neurologica, Università Tor Vergata, Via Orazio Raimondo 18, 00173 Rome, Italy ; Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy.
Carlo
C
Caltagirone
Department of Clinical and Behavioural Neurology, IRCCS Santa Lucia Foundation, Via Ardeatina 306, 00179 Rome, Italy.
Alberto
A
Costa
D000293:Adolescent; D001288:Attention; D001930:Brain Injuries / Q000150:complications / Q000523:psychology*; D056344:Executive Function; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000523:psychology*; D061212:Memory, Episodic; D008570:Memory, Short-Term; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000293:injuries*; D055815:Young Adult