3 limoli, ciocchetti, silari di corato, effect of intermittent light stimulation mnemosline on visua

TITLE: Effect of Intermittent Light Stimulation MNEMOSLINE on visually impaired patients AUTHORS (LAST NAME, FIRST NAME): Ciochetta Ilaria1 ; Solari, Roberta1 ; Di Corato, Riccardo 1 ; Limoli, Paolo G. 2 INSTITUTIONS (ALL): 1 Orthoptic, Centro Studi Ipovisione, Milan, Mi, Italy Centro Studi Ipovisione, Milan, Mi, Italy

INTRODUCTION Visual rehabilitation is a therapeutic approach that has been applied to different ocular diseases characterized by visual deterioration and loss of visual acuity.

Nowadays the Effects of neural photostimulation during visual rehabilitation are well know.

Neuroelectrical information can by–pass disfunctional retinal cells reaching indirectly visual cortex. Visual training, through reiterated stymuli, activates existing synapses, increases the identification of these stimuly allows the formation of new synapsis. 1 The neural photostimulation contributes to the creation of neurovisual nets, causing an amplification of visual perception when compared with visual perception obtained with previous retinal conditions.1 The principle is to electrically stimulate neurons along the visual pathway. Ocular approaches target the remaining retinal cells whereas brain stimulation aims at stimulating higher visual structures directly.2 The classical Visual Training is a set of methods aimed at optimising residual vision, or improving fixation quality and stability (sound healing biofeedback), or visual field sensitivity (photostimulation) by stabilizing and/or relocating the preferential retinal location (PRL) in a much more useful area of the retina thus increasing fixation stability, probably using the residual cerebral plasticity in the adult visual cortex.3 The neural photostimulation methods use cerebral plasticity and neurosensorial adaptation to the central scotoma of patients with macular diseases to improve their visual abilities and more manageable visual aids.

2

Ophthalmology,

Audio feedback and pattern stimulus facilites transmission between intraretinal neurons as well as between the retina and the brain, where the highest degree of stimuli processing takes place, thereby supporting a “remapping phenomenon”.4 Microperimetric biofeedback trains the neurotrasmission chain to increase intercellular neurotransmitters and to restore neuro-brain connections faster than in normal conditions.5-6 In addition to the classic systems of visual training there are news home device.

The aim of these home devices is to continue the visual stimulation at home strenghthen the traditional outcomes and facilitate the visual training of visually impaired patients One of the first news home devices available is Mnemosline®, use in neurology.

PRUPOSE: To evaluate the effects of intermittent light stimulation delivered by therapeutic glasses MNEMOSLINE ® on Visually Impaired patients.

The mnemosline device is an eye mask which in place of the lenses contains two red LEDs (650 nanometres, 7 uW of radiant power at 2 cm, pulsed) with flash frequency centred on the frequencies of the brain's alpha rhythm.

Over Time, this prolonged stimulation causes an increase in the amplitude and a shift in the frequency of the apha waves of the person subjected to pulsed radiation 7-8 The statistical data collected showed that whit this stimolation it was possibile to obtain an improvement of memory and, simultaneously, an icrease in the amolitude and regularity of the alpha rhythm(measured through spectral density).9-10-11

The aim of this work is to demonstrate if the light stimulation MNEMOSLINE ® are able to promote an increase in visual performance.

METHODS: We included in the research 7 patients (13 eyes) visually impaired for different diseases (dry AMD, RP, Best, stroke, glaucoma and high myopia) (mean age 66.7 range 48-85 aa) For each patient was evaluated before stimulation with MNEMOSLINE ® (T0) BCVA (logMAR) , close up visione (cp) and reading speed (p / m) with a magnifying aid.

Each patient wore the glasses MNEMOSLINE ® for a complete cycle of intermittent stimulation (10 minutes) so (T1) BCVA, close up visus and reading speed have been revalued (reading text was different from the previous one, same pts).

We also asked patients a subjective comment about the immediate results post-stimulation.

RESULT: Functional changes following MNEMOSLINE stimolation are:

BCVA: from 0.71 to 0.53 logMAR (33.96 % ) increasing in 12 of 13 eyes (92,3%) Close up visus: from 30.31 pts to 25.28 pts (19.90% ) increasing in 11 of 13 eyes (84,6%) vl : from 56 to 79 p/m (41.07%) increasing in 7 of 7 patients (100%) 4 patients note subjectively improved of visual performances after stimulation 100% of patients reported an improvement of one of the parameters considered.

CONCLUSION: We can say that the stimulation by Mnemosline carried out ten minutes before the assessment is effective in increasing the functional parameters considered.

It remains to consider a larger sample size and duration of the effectiveness of the stimulation.

In addition, there are differences depending on the category rehabilitative considered that should be better analyzed.

Mnemosline could be an alternative or addition to the usual home-visual training techniques used in visual rehabilitation centers.

REFERENCES 1.

Limoli PG, Vingolo EM, D'Amato L, Giacomotti E, Solari R, Costanzo P, Ribecca A, Venturi N. Effects of neural photostimulation on reading performances during visual rehabilitation. Proceedings ARVO 2004 - USA. 2.

Lorach H1, Marre O, Sahel JA, Benosman R, Picaud S. Neural stimulation for visual rehabilitation: advances and challenges. J Physiol Paris. 2013 Nov

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Vingolo EM, Salvatore S, Limoli PG.MP-1 Biofeedback: Luminous Pattern Stimulus Versus Acoustic Biofeedback in Age Related Macular degeneration (AMD). Appl. Psychophysiol. Biofeedback. 2013 Mar;38(1):11-6. doi: 10.1007/s10484-0129203-4.

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Vingolo EM, Limoli PG, Fragiotta S, De Rosa V, Domanico D. BCEA evaluation after pattern stimulation in wet AMD patients. Proceedings of ARVO 2013 – USA. 5.

Vingolo EM, Salvatore S, Domanico D, De Rosa V, Limoli PG. Visual performance recovery after retinal Detachment surgery with microperimetric biofeedback. Proceedings of ARVO 2012 – USA 6.

Limoli PG, Vingolo EM, D'Amato L, Giacomotti E, Solari R, Costanzo P, Ribecca A, Di Corato R, Gilardi E. Integrated neural photo-stimulation and microperimetry fixation analysis, clinical experience of the Low Vision Research Centre of Milan. Proceedings ARVO 2006 – USA 7.

Babiloni C., F.Babiloni, F.Carducci et Al.: Human cortical EEG rhythms during long term episodic memory task. A highresolution EEG study of the HERA model.Neuroimage, 21:1576-84, 2004. “…high resolution study of brain rhythmicity during visual episodic memory recognition task…the strict relation between gamma response and perception suggest that retrieval processes of long term memory deeply impinged upon sensory representation of the stored material…”

8.

Ferro Milone F., V. Nofrate, A. Porro: Enduring intermittent photic stimulation enhances dynamic activity of the EEG and memory processes. Rivista Ital. Neurobiol., (4), 209-218, (2004). “…spectral analysis in AD patients shows a nonsignificative difference between photo-stimulated and non photo-stimulated EEG at the initial stage, but significative between the last stage and more significative between the initial and final stage of stimulation (ANOVA p<0,01)… Rivermead test application (double form) shows significative improvement of the behavioural memory between initial and final stage (6 month SLI)(ANOVA p<0,01)…”

9.

Balduzzo,M., F. Ferro Milone, T.A. Minelli, I. Pittaro Cadore and L. Turicchia: Mathematical phenomenology of neural synchronization by periodic fields, Nonlinear Dynamics, Psychology and Life Sciences 7, 115-137 ,2003. “…Neuron synchronization has been hypothesized as the basic mechanism leading neurological phenomena like low electroencephalographic rhythm dimension and high coherence….cognitive processes such as associative memory can also b explained in term of neuron synchronization…”

10.

Angeleri, F., F. Ferro Milone and S. Parigi: Electrical activity and reactivity of the rhynencephalic, pararhynencephalic and thalamic structure: prolonged implantation of electrodes in man, EEG Clin. Neurophysiology, 16: 100129,1964. “…gli AA.presentano il primo risultato, in Italia, di registrazione e stimolazione di strutture profonde dell’encefalo umano in una prospettiva di terapia chirurgica con metodo stereotassico, di alcune forme di epilessia del lobo temporale…”

11.

Klimesch, W.: EEG-alpha rhythms and memory processes. Intern. J. Psychophysiol., 26 (1997) ”…the calculation of changes in band power indicate further that the upper alpha band is particularly sensitivwe to semantic memory demands….the lower alpha band seems to reflect attentional processes…these findings are discussed on the basis of an hypothesis, which assumes that EEG frequences within the alpha band, stem at least in part from the thalamus, and that the activity of the thalamo-cortical networks reflects processes that are related to searching, accessing and retrieving information from semantic long term memory…”