|Yerba Buena Island, San Francisco Bay|
Within days of Williamson's disappearance, Brooks gave three confessions to friends. He provided graphic details of how he bludgeoned her to death with a hammer after a drunken quarrel. He even took one friend to the location where he had tossed her body into the Bay; there, police later recovered blood samples that matched Williamson's DNA.
The couple’s 16-year relationship had always been tumultuous, but it was deteriorating in the weeks before the killing. Brooks had resumed smoking crack cocaine and had openly threatened to kill Williamson if she left him, according to trial testimony.
|Bruce Brooks. Photo credit: M. Macer, S.F. Chronicle|
A defense-retained neuropsychologist, Myla Young, testified that Brooks had frontal lobe damage that might cause him to begin a repetitive act like hitting and not stop until worn out. The impairment also made him prone to amnesia, she said.
But the jury wasn't buying. After three days of deliberations, jurors convicted Brooks of second-degree murder. He was sentenced to 15 years to life.
Appeal: Unfair to exclude SPECT evidence
Brooks appealed, citing the trial judge's exclusion of Single Photon Emission Computed Tomography (SPECT) evidence. He had hoped to introduce the colorful brain scans to convince the jury he had organic brain damage that made it impossible for him to premeditate a murder, or even form a conscious intent to kill. Psychiatrist Daniel Amen was prepared to testify that Brooks' scan, which measures blood flow to certain regions of the brain, looked "very abnormal."
San Francisco trial judge Cindy Lee excluded the SPECT testimony based on concerns about both the method and the messenger.
|Daniel Amen promotes his Amen Clinics|
Regarding the method, the judge ruled that research has not established that SPECT scans can accurately determine cognitive impairment, much less impairment so severe as to preclude the requisite mental states for premeditated murder. While the scans were "pretty glitzy" and "high tech," their colors lacked meaning and had a high potential to confuse the jury, she said.
As to the messenger, the judge had "a 'considerable question' ... as to whether [Amen] is an independent and unbiased expert and truly represents a cross-section of the relevant scientific community," according to a just-issued appellate ruling.
The First District Court of Appeal upheld the trial judge's ruling, endorsing her concerns about both the method and the messenger.
The appellate justices were unable to find any published appellate decision on the issue of whether SPECT evidence is admissible in a criminal trial to support a theory that a defendant's ability to form a specific intent was impaired by organic brain damage. So they conducted their own independent review of the scientific status of SPECT evidence. They were ultimately under-impressed.
[W]e agree with the trial court that defendant failed to establish that SPECT was generally accepted by the scientific community as showing brain injuries that were relevant to the defense theory that he did not form the intent necessary to commit murder. Defendant did not establish a generally accepted correlation between blood flow to a particular part of the brain and any particular behavior…. [A]s the trial court correctly summarized the testimony, "[T]here’s a lack of any testimony that there’s any quantitative percentage of blood flow, specific cognitive functions or other factors that will be impaired or even affected."
Regarding the messenger, the appellate justices said it was within the trial judge's discretion to raise "serious questions about Amen’s qualifications to testify as an expert witness. The court doubted that he could be independent and unbiased in light of his long engagement in significant entrepreneurship activities regarding SPECT via the Amen Clinics and activities as a proponent of the utility of SPECT scan imaging."
Amen's methods questioned
Judge Lee and the appellate panel were not alone in viewing Amen's activities with suspicion.
Amen, a graduate of the now-defunct Oral Roberts University School of Medicine, has said he was "led by God to pursue this work." And the missionary zeal with which he promotes SPECT for everything from depression and anxiety to aggression and drug abuse has raised concerns among other medical professionals.
In 2005, Amen's unconventional treatments had caught the attention of Quackwatch, an international network dedicated to exposing medical "frauds, myths, fads, fallacies, and misconduct." Three years later, Salon ran a piece by neurologist Robert Burton, criticizing PBS for running Amen's "self-produced infomercial" touting his unproven intervention for Alzheimer's disease:
It’s hard to dismiss the religious undertones of Amen’s work…. And yet Amen’s sense of calling hasn't led him to undertake the high-quality clinical investigations that would lend scientific credence to his claims…. Amen states that he has read more than 40,000 SPECT scans and holds himself up as a world expert. But a brief quote from his TV special quickly reveals a very peculiar method of determining what constitutes a normal SPECT scan…. Using Amen’s figures from his TV program, only 3 percent of those he has studied have been interpreted by himself and his staff as being normal. Put another way, 97 percent of patients who attend Amen’s clinic can expect to be told that their SPECT brain scan is abnormal.
But the controversies surrounding neuroimaging in court go far beyond those swirling around Amen and his SPECT scans. Echoing the trial judge's concerns in the Brooks case, the UK Royal Society just this week warned that jurors may be far too impressed with brain images, not recognizing their limited applicability to real-world legal questions.
POSTSCRIPT: On Feb. 29, 2012, the California Supreme Court denied review of the case.