On remand from the Supreme Court, on April 27, 2015, the Federal Circuit reassessed whether Biosig’s claims were indefinite, this time under the “reasonable certainty” test, and once again found the claims not indefinite under 35 U.S.C. § 112 ¶ 2.

Claims of the asserted patent are directed to a heart rate monitor that measures bioelectrical signals from two electrodes that are in “spaced relationship” with each other. The issue of indefiniteness, as framed by the court, hinged on whether the intrinsic record provided “some standard for measuring [the] degree” of “space relationship,” such that a person of ordinary skill in the art would be informed, with reasonable certainty, of its scope. Turing to the specification, the court found that the relationship could be “neither infinitesimally small nor greater than the width of a user’s hands.” The court then examined arguments made during prosecution – where the applicant argued that the spaced relationship must allow for “substantial removal of [a first particular signal type] from [another]” – and reasoned that a skilled artisan would be able to determine such a relationship by “calculating the point in which the [first] signals are substantially removed.” Thus, the could held, “a skilled artisan would understand the inherent parameters of the invention as provided in the intrinsic evidence,” reasoning “the term ‘spaced relationship’ does not run afoul of ‘the innovation-discouraging zone of uncertainty against which [the Supreme Court] has warned,’ and to the contrary, informs a skilled artisan with reasonable certainty of the scope of the claim.”

Biosig Instruments, Inc. v. Nautilus, Inc. No. 2012-1289 (Fed. Cir. April 27, 2015)(J. Wallach).