# Triangular Neural Synchronization Patterns in Visual Impairment: A Comprehensive Case Series Exploring Multi-node Network Dynamics and the Neural Triangle Index

## TL;DR

This study explores triangular brain activity patterns in visually impaired individuals, introducing a new biomarker called the Neural Triangle Index to better understand compensatory brain changes.

## Contribution

The study introduces the Neural Triangle Index as a novel biomarker for multi-node neuroplasticity in visual impairment.

## Key findings

- Congenitally blind participants showed significantly higher Neural Triangle Index values compared to acquired blind individuals and sighted controls.
- Alpha-band coherence and phase-locking values were enhanced in congenitally blind participants, indicating stronger frontal synchronization.
- Distinctive triangular timing patterns were observed in congenital blindness, showing tight frontal and extended fronto-parietal coordination.

## Abstract

Background: Compensatory neural plasticity in visual impairment involves complex reorganization of multi-node networks that goes beyond conventional bilateral connection analysis. Triangular synchronization patterns, representing coordinated activity among three cortical sites simultaneously, remain unexplored despite their potential to reveal fundamental mechanisms underlying compensatory neuroplasticity.

Objective: This study aimed to conduct a case series examining triangular neural synchronization patterns in visual impairment and introduce the Neural Triangle Index (NTI) as a proof-of-concept biomarker for multi-node neuroplasticity.

Methods: We studied seven participants: four with congenital blindness, two with acquired blindness, and one sighted control. Participants performed simulated navigation tasks during EEG recording from AF3, AF4, and Pz electrodes. We computed coherence across frequency bands, phase-locking values (PLVs), and the newly developed NTI, integrating temporal delays and spectral coherence.

Results: Congenitally blind participants demonstrated elevated NTI values (range: 10.5-16.8, mean: 13.37±2.6) compared to acquired blind individuals (6.2-8.4, mean: 7.30±1.6) and sighted controls (1.07). Alpha-band coherence between frontal electrodes was enhanced in congenital cases (0.84±0.08) versus acquired cases (0.55±0.18) and controls (0.34). Phase-locking demonstrated exceptional stability in congenital blindness (PLV: 0.85±0.04) with distinctive triangular timing patterns characterized by tight frontal synchronization and extended fronto-parietal coordination.

Conclusions: This case series provides the first evidence for distinctive triangular neural synchronization patterns in visual impairment. The NTI demonstrates promise as a neuroplasticity biomarker, capturing multi-node network dynamics invisible to conventional pairwise analyses. While limited by sample size, these findings establish methodological foundations and generate hypotheses for large-scale validation studies.