From Paper to Silicon Chips - EEG Standardization in the Digital Age (1990-2010)

The Digital Transition: When Paper Became Obsolete

The last decade of the 20th century and the early years of the new millennium marked a historic turning point in clinical neurophysiology. While the 1970s and 1980s had introduced the digitalization of the EEG, it was during the 1990s and 2010s that this technology fully matured, transforming not only the way brain activity is recorded, but also the way it is interpreted, reported, and shared medical knowledge.

The Pioneers of Digital Standardization

The First Computerized Reporting Systems

Contrary to what many believe, the first attempts at computerized standardization of EEG reporting began surprisingly early. As early as the 1980s, Robert R. Young and Keith H. Chiappa at Massachusetts General Hospital developed a homegrown software package for reporting EEG findings, where fixed terms could be selected and reports generated semi-automatically.

But it was Harald Aurlien and his colleagues who took the most significant step. Starting in 1998, they began using a software package called "Holberg" to report EEG findings and automatically generate databases. This system allowed for the reporting of more than 36,000 EEG studies by 2013, laying the groundwork for what would eventually become the SCORE system.

The Johns Hopkins Legacy

In parallel, at Johns Hopkins, Ronald Lesser and his colleagues developed a software package called "Reporter" starting in 1998 that standardized terms in EEG descriptions, allowing keyword searches. By 2013, they had prepared more than 38,000 reports using this software.

The IFCN Standards Revolution

The 1998 Digital Standards

A pivotal moment came with the publication of the "IFCN standards for digital recording of clinical EEG" in 1998. These standards, developed by the International Federation of Clinical Neurophysiology, established for the first time the minimum technical specifications for the digital recording of clinical EEG, addressing key aspects such as:

• Standards for digital electroencephalography

• Shape and recording control

• Computer-aided signal processing

• Standardized terminology

The High-Density Era

The 1990s saw the development of high-density EEG (HD-EEG) systems that provided much finer spatial resolution. These technological improvements not only increased diagnostic accuracy but also created an urgent need for new standardization protocols to handle the additional complexity of the data.

The Digital Tower of Babel Problem

The Crisis of Interpretation

By the early 2000s, an unexpected problem had emerged: the fragmentation of terminology. While digitalization had solved many technical problems, it had created a new and fundamental one. As the researchers noted, "In practice, a wide variety of local terminologies flourish, where the same term is used with different meanings in different centers, and the same characteristic is described with different terms in different centers."

This terminological Babel potentially contributed to the previously described low inter-observer agreement for EEG. However, when electroencephalographers had to assess specific EEG characteristics by choosing from a list of predefined terms, inter-observer agreement was significantly higher.

The Need for Computerized Tools

Specialists realized that computerized tools were needed to:

1. Improve the quality of EEG evaluation and interpretation

2. Increase inter-rater agreement in the reporting of findings

3. Build large databases for clinical research

4. Constitute a valuable tool for education

The First Steps Toward SCORE

The Consensus Workshops (2010-2011)

The turning point came with the consensus workshops held in Dianalund, Denmark, in 2010 and 2011. A working group of EEG experts participated in these workshops, with the faculty approved by the European Affairs Committee of the International League Against Epilepsy (ILAE).

The SCORE working group, composed of 25 clinical neurophysiologists/epileptologists from 15 European countries, developed a consensus proposal intended to reflect the needs and practices in different countries and centers.

Software Development (2010-2013)

Based on consensus, the SCORE software was developed by a group of programmers at Holberg EEG AS. The process was iterative, taking three years of development, with successive versions tested by scoring EEG recordings in clinical practice. In total, more than 2,000 recordings were included in this process, with four major revisions made.

The First Version of SCORE (2013)

The Consensus European

In 2013, the first version of SCORE was published as a European consensus, endorsed by both the IFCN European Chapter and the International League Against Epilepsy (ILAE) - European Affairs Committee. This template helped develop unified terminology and criteria for non-convulsive status epilepticus.

Key Elements of the System

SCORE incorporated the following main elements:

• Patient's personal data

• Indication data

• Recording conditions

• Modulators/procedures

• Background activity

• Drowsiness and sleep

• Interictal findings

• "Episodes" (clinical or subclinical events)

• Physiological patterns

• Patterns of uncertain significance

• Artifacts

• Polygraphic channels

• Diagnostic significance

Big Databases: The Power of Standardization

The Danish Epilepsy Center

A modified version of the Holberg software was used to report all standard EEG reports at the Danish Epilepsy Center since 2009. The automatically generated database during reporting made it possible to address specific questions related to certain aspects of the EEG, leading to three additional publications.

International Expansion

By 2013, when the first version of SCORE was published, it had already demonstrated its practical value. More than 36,000 EEG studies had been reported using Holberg software, and the Reporter system at Johns Hopkins had generated more than 38,000 reports.

The Impact on Clinical Practice

Improved Diagnostic Quality

Digital standardization from 1990 to 2010 brought significant improvements:

1. Reduced subjectivity: Standardized systems forced clinicians to use accurate and consistent terminology.

2. Improved traceability: Digital databases enabled longitudinal patient follow-ups.

3. Facilitated research: Standardized data made large-scale multicenter studies possible.

4. Improved education: The systems provided consistent training tools.

Persistent Challenges

Despite the advances, significant challenges remained:

• Technological variability: Different laboratories used equipment with divergent specifications.

• Lack of widespread adoption: Systems remained primarily in local use.

• Diverse cultural needs: Different medical traditions require adaptive approaches.

The Legacy of the 1990-2010 Period

Preparing for the Global Era

The work done during these two decades laid the fundamental foundations for What would become the international SCORE system. Pioneers such as Harald Aurlien, Ronald Lesser, and the teams at Massachusetts General Hospital created not only technical tools but also a culture of standardization in clinical neurophysiology.

The Cultural Transformation

Perhaps the most important change was not technological, but cultural. The neurophysiology community began to recognize that standardization did not limit medical expertise, but rather enhanced it, allowing for more accurate comparisons, more robust research, and better patient care.

Conclusion: The Foundations of Modern Medicine

The period 1990–2010 represents a pivotal chapter in the history of medicine. During these two decades, clinical neurophysiology transformed from a discipline dependent on paper and subjective interpretation to a science based on standardized digital data.

This history reminds us that the most transformative medical advances are not always the most visible. While the public celebrates new medications or surgical techniques, it is often improvements in standardization, documentation, and information systems that truly revolutionize medical practice and improve patient outcomes globally.