Prismatic lenses refers to a device that allow a controlled deviation of the visual
field. Prismatic lenses are commonly used in the treatment of stroke patients with
neglect symptoms. Neglect is a neuropsychological disorder characterised by an asymmetric
processing of bodily and sensory information in which patients fail to attend to stimuli
in the contralesional space. Prismatic lenses are considered as a bottom-up approach in
the rehabilitation of neglect, inducing a temporary automatic shift of the attention
towards the neglected space. While wearing goggles with prismatic lenses, patients are
asked to perform a pointing task requiring the reorganization of visuo-motor coordinates
to point to the target correctly. During the initial phase of the pointing task, patients
typically misreach the target in the direction of the visual displacement (direct
effect). After a few trials, normal accuracy is restored. After removing the prisms,
subjects typically misreach the target in the direction opposite to that of the original
deviation. This phenomenon is known as after effect (AE). The whole process of
sensori-motor adaptation is called prism adaptation (PA). Some studies estimates that a
single session of PA can mitigate neglect symptoms for almost 1 hour, and a treatment
with PA for 2 weeks can ameliorate symptoms for 6 months. Recently, prismatic lenses have
been used also in the healthy population as a tool to induce non-invasive neuromodulation
of brain networks. Indeed, PA is thought to increase cortical excitability of frontal and
parietal regions ipsilateral to the induced deviation. PA effects been studied using
electrophysiological and neuroanatomical techniques. In the first case, Bracco and
colleagues (2018) found a modulation of EEG activity implied in motor preparation during
PA. In the second case, Wilf and colleagues (2019) observed a more efficient switch
between default mode network and attentive network following PA. Moreover, a recent study
reported that PA could affect also motor outcomes, such as plantar pressure and handgrip
strength.
Recently, Restorative Neurotechnologies S.r.l. created Mindlenses Professional, a new
digital tool that combines PA with serious games for cognitive rehabilitation. Both PA
and seirous games are performed using a tablet. Concerning PA administration, black
squares are presented in the centre, on the left or on the right of the screen. Patients
are required to touch the black square with rapid and precise movements. Mindlenses
combines the neuromodulatory potential of PA to increase the rehabilitative outcomes of
the digital exercises. Preliminary results showed that the combination of these two
techniques can ameliorate attention and executive function.
Mindlenses professional includes 12 assessment tasks and 7 rehabilitation exercises,
which encompass 6 cognitive domain: attention, visual search, memory, learning, working
memory and language. The 12 assessment tasks do not replace a full neurpsyhcological
evaluation, but can be informative on the patient's cognitive functioning and allow the
clinician to identify patient's difficulties. From the perfoemances at these tasks, the
clinician can schedule a rehabilitation program tailored on the patient's need. The
treatment consists in 10 sessions in which the patient performs both PA and serious
games.
The aim of this project is to validate Mindlenses Professional in patients with stroke or
with mild cognitive impairment (MCI).
Mindlenses efficacy will be evaluated in terms of changes in cognitive and motor
performance before and after the treatment, compared to a treatment using only serious
games and to conventional cognitive rehabilitation. Moreover, patients' neuroimaging data
will be acquired to explore whether vascular lesions or atrophy in specific brain regions
could affect the PA performance and the efficacy of the treatment. Lastly, changes in
brain plasticity, assessed as plasma levels of the brain derived neurotrophic factor
(BDNF), before and after the treatment will be investigated.
