Three-Level Hypothesized Explanation of the IM effect (McGrew, 2012)

Interactive Metronome® (IM) is believed to improve the resolution and efficiency of an individual’s internal brain clock(s) and temporal processing. In turn, it is hypothesized that this results in more efficient brain connectivity, communication, and synchronization via increased integrity of the brains white matter tract communication system, producing more efficient communication between critical brain networks. In particular, research and theory suggests that IM training increases the efficacy of the parietal-frontal brain network, the brain network most associated with general intellectual functioning, working memory, controlled attention and executive functions.

The primary conclusions from the detailed scientific explanation of the IM are:

1. The diversity of performance domains positively impacted by IM technology is due to IM improving the function of crucial brain-based domain-general neurocognitive mechanisms.
2. The precise, real-time IM millisecond feedback impacts the temporal processing resolution of the internal brain clock, which in turn improves neural efficiency—and thus, more efficient temporal and information processing in the brain.
3. The IM effect appears to be the result of increased efficiency and synchronization of communication between the primary brain structures that comprise the functional brain networks involved in performing both the cognitive and motor demands of IM training.
4. IM technology may be improving brain network communication, especially within the major brain networks at the core of the P-FIT (parietal-fontal integration) model of general intelligence. IM technology may be improving the efficiency of the parietal-frontal brain network which is critical to general intellectual functioning, working memory, controlled attention, and overall cognitive efficiency.
5. One of the most important IM training outcomes (but not the only outcome) is improved focus via increased efficiency of the attentional control system (ACS) that maintains goal related information active in working memory in the presence of internal (mind wandering) and external distractions. Improvement in efficiency of executive functions and working memory results in more efficient complex cognitive processing and learning.