Temporal Disorders in Left and Right Brain-Damaged Patients

Time is an important function that permeates our everyday activities but it has been so far significantly under-investigated in neurological patients.

For instance, it is known that right brain damaged (RBD) patients with spatial attentional deficit (neglect) are impaired in both the ability to estimate the duration of an event (Time Estimation), showing a time underestimation, and the ability of mentally moving in past and future time (Mental Time Travelling), showing a deficit in processing future events when they are projected in the past. After a leftward shift of spatial attention induced by prismatic adaptation (PA), both the underestimation and the ability to travel in time ameliorate. However, less is known about these abilities in left brain damaged (LBD) patients.

Aims of this study are to investigate:

i) the performance (in terms of accuracy and reaction times) of LBD and RBD patients on Mental Time Travelling; ii) the correlation between Mental Time Travelling and Time Estimation abilities; iii) the efficacy of a single session of PA inducing a leftward (L-PA) and a rightward (R-PA) attentional shift on Mental Time Travelling and Time Estimation abilities.

A group of control subjects will be involved for comparison among groups.

Time processing involves different abilities - i.e. estimating the duration of an event (Time Estimation) and moving in past and future time (Mental Time Travelling) - and it is a fundamental ability in everyday life. However, in neuropsychology, time processing is routinely neglected in the assessment of cognitive deficits in brain-damaged patients. This is surprising since time is an important function that permeates our activities: it is involved in perceiving mismatches in lip reading (milliseconds), estimating how long it takes to be ready for work (minutes), and planning how long it will take a manuscript to be accepted (usually months). Thus, impairment in processing time has important consequences in daily life.

For instance, it is known that right brain damaged (RBD) patients with spatial attentional deficit (neglect) underestimate durations of milliseconds and show a deficit in processing future events when they are projected in the past.

Moreover, previous studies have demonstrated that a leftward shift of spatial attention induced by prismatic adaptation (PA) determines an amelioration of both, time underestimation and the deficit in mental travel in time.

The Mental Time Travelling, in particular, seems to involve different cognitive functions, among others, episodic memory and the ability to anticipate the future. Recent evidence suggests that these functions are mediated by neural circuits localized in the left hemisphere but no studies have investigated the ability of mentally moving in past and future time in left brain damaged (LBD) patients.

Aims of this study are to investigate:

i) the performance (in terms of accuracy and reaction times) of LBD and RBD patients on Mental Time Travelling; ii) the correlation between Mental Time Travelling and Time Estimation abilities; iii) the efficacy of a single session of PA inducing a leftward (L-PA) and a rightward (R-PA) attentional shift on Mental Time Travelling and Time Estimation abilities.

A group of control subjects will be involved for comparison among groups.

Eligibility Criteria:
Inclusion Criteria:

* patients with focal (right or left) brain-damage

Exclusion Criteria:

* generalized cognitive impairment (score lower than 24 at the Mini Mental State Examination)
* psychiatric disorders
* additional neurological disorders
* abusive use of alcohol or illicit drugs