Dimensional Analysis: An Alternative Method for Converting between Interrelated Units of both Timebase and Sensitivity in EEG

ABSTRACT

Neurodiagnostics professionals expected to perform EEG calculations involving timebase and sensitivity may benefit from an additional method in which to solve for the answers. Dimensional analysis (DA) is an efficient, organized method that generates answers in a consolidated context. Its coherent, streamlined mechanism allows for efficient computations involving sets of values with diametric units. One of its key advantages is its ability to emphasize conceptualization, which may be attractive to those with that mathematical personality. Its usefulness beyond neurodiagnostics is profound and includes assisting domestically inclined individuals with mathematical conversions related to home projects and proper cooking times. Several examples of both EEG and home-life applications are provided to assist with acclimation.

KEY WORDS:

• Dimensional analysis
• EEG
• sensitivity
• timebase
• scale legend

Notes

^1. The entire span of the horizontal component within the cross performs as a vinculum.

^2. The width is representative of the length of 1 second as viewed on the EEG screen.

^3. Within this publication, it is advised to use the frequency and duration equations separately; they are not involved in DA crosses.

^4. Note that as the vertical and horizontal components of the scale legend change, proportionally so do the dimensions of the EEG waveform (Kelly 2009), as long as the height and width ratio of the epoch containing the wave is maintained. Thus, the answer (wave duration, amplitude) can always be found if the wave height(s) and width(s) are measured along with the scale legend.

^5. The author suggests that once the reader has reviewed the entire article, they revisit Figures 9B and 9C and use DA to solve for the amplitude of the PDR wave (49 µV).

^6. A quick Internet search can provide ratios such as “cups per tablespoon.” In addition, many cookbooks and home reference texts contain comprehensive conversion tables.