This published article by Cohen (Dermatol Surg, 2008) describes a device and method for measuring hair loss and growth. It details the prototype device upon which the HairCheck device was based, and contains a comprehensive list of alternative hair measuring methods. It describes the multiple tests performed on the Trichometer to establish its sensitivity, precision, accuracy, and its ability to discriminate changes in diameter and density. It also compares the device's accuracy with that of dry hair weight measurement -- the industry gold standard. A commentary by Dow Stough, MD follows the article. Note: The term Trichometric Index (TI) is used in this text. This term has since been replaced by the term Hair Mass Index (HMI).
In this comprehensive article by Wikramanayake et al, (Inter J of Trichology, 2012) the authors evaluate the commercial HairCheck trichometer, with the same bench-testing methods used by Cohen to test his original prototype device (Derm Surg 2008). The authors conclude that the HairCheck device has the same accuracy (as validated by comparison to dry hair weight), precision, and reproducibility as the prototype, but with slightly lower sensitivity. They further conclude: Cross Section Trichometery (CST) generates meaningful and quantitative guidelines that can be used in the everyday management of male and female patients with alopecia and hair breakage. CST can be used to monitor progressive hair loss, regardless of etiology. CST has the unique ability to measure a patient’s response to minoxidil, finasteride, and laser therapy; and detect the response to dosage changes and combinations treatments. A summary poster of this article is available below.
This poster was prepared by the authors of the above article and summarizes the findings that the authors published in the International Journal of Trichology. It was prepared for display at various hair science meetings.
This chapter (Chapter 11, Hair Transplantation, Unger and Shapiro, Informa, 5th Edition) from the foremost textbook on hair restoration surgery, describes the theory of cross section trichometry, the device itself, and its clinical applications. Although somewhat brief, it provides an introductory overview of the subject and contains excellent photographs.
In this published article Hendriks, et al (Derm Surg, 2012) evaluate the no-tattoo locating device that is provided in the HairCheck hair measuring system when used in combination with the bundle-measuring trichometer device. The authors report that multiple Hair Mass measurements of a non-tattooed site by multiple operators can be performed with "high reproducibility."
In this published article by Vleut, et al (Support Cancer Care, 2013) the HairCheck device is used by a group of cancer specialists to measure chemotherapy induced alopecia (CIA). They compare Hair Mass Index (HMI) values with three other parameters that are commonly used to quantify hair loss in CIA patients. They conclude that HMI values are quantitatively more precise than the other three non-mechanical measuring methods. Fearing pattern hair loss might be also be present in their CIA patients, they did not measure along the midline (as per protocol) , but in the temporal area instead. Interestingly, they demonstrated that the HairCheck device may be used in the temporal area with minimal regard to its exact positioning. Apparently there is little variation in the HMI within the general temporal region of the scalp.
CROSS SECTION TRICHOMETRY USED TO MEASURE THE EFFECT OF A NUTRITIONAL SUPPLEMENT ON FEMALE PATTERN HAIR LOSS
In this published article by LeFloc'h, et al, J Cosmet Dermatol, 2015) the HairCheck device was used in tandem with trichograms, anagen telogen ratios, and patient self evaluation. The study was designed to measure the efficacy of supplemental omega 3&6 and antioxidants as a treatment for female androgenetic alopecia.
This published article (in Hair Transplant Forum 2009, also Hair Transplantation, Unger & Shapiro, Informa, 5th Edition) describes a simple visual method to quantify hair loss. It uses no more than a pencil and printed graphic. It provides a map with 8 numbered scalp zones and generates a bar graph that defines the distribution of the loss and its severity in each zone. The system addresses the limitations of the Hamilton-Norwood classification, and clarifies the ambiguity of terms used to describe scalp topography and hair loss severity.