Brain Circulation during Panic Attack: A Transcranial Doppler Study with Clomipramine Challenge.

Introduction. Cerebral blood flow has been well studied in patients with panic disorder, but only few studies analyzed the mechanisms underlying the onset of a panic attack. The aim of the present study was to monitor the cerebral hemodynamics modifications during a panic attack. Materials and Methods. 10 panic disorder patients with recent onset, fully drug naïve, were compared to 13 patients with panic disorder with a previous history of treatment and to 14 controls. A continuous bilateral monitoring of mean flow velocities in right and left middle cerebral arteries was performed by transcranial Doppler. Clomipramine was chosen as challenge. Results. Eight out of 10 patients drug naïve and 6 control subjects out of 13 had a full blown panic attack during the test, whereas none of the patients with a history of treatment panicked. The occurrence of a panic attack was accompanied by a rapid decrease of flow velocities in both right and left middle cerebral arteries. Discussion. The bilateral acute decrease of mean flow velocity during a panic attack suggests the vasoconstriction of the microcirculation of deep brain structures perfused by middle cerebral arteries and involved in the so-called "fear circuitry," thus suggesting that cerebral homeostatic dysfunctions seem to have a key role in the onset of a panic attack.

The relevance of early TCD monitoring in the intensive care units for the confirming of brain death diagnosis.

Brain death (BD) diagnosis is the clinical assessment of the irreversible loss of function of the entire brain, including the brainstem. Transcranial Doppler (TCD) examination is used in several countries as a confirmatory test to assess cerebral circulatory arrest (CCA). A total of 1,400 TCD examinations were performed in 623 patients (pts) admitted to intensive care units (ICUs) of our hospital during the last 6 years. Oscillating flow, systolic spikes and the absence of any TCD signal were considered as diagnostic patterns of irreversible CCA. TCD patterns of CCA were detected in 56 pts. In 25 pts, deeply sedated with barbiturate therapy, TCD was employed as confirmatory test for BD diagnosis and 14 of them could become organ and/or tissue donors. TCD is a safe and inexpensive tool that can be performed at the bedside, and it allows to shorten the diagnostic process of BD, which is the prerequisite for organ donation.

Cerebral hemodynamic lateralization during memory tasks as assessed by functional transcranial Doppler (fTCD) sonography: effects of gender and healthy aging.

INTRODUCTION: Previous neuropsychological, lesional and functional imaging studies deal with the lateralization of memory processes, suggesting that they could be determined by the stage of processing (encoding vs retrieval) or by content (verbal vs non-verbal stimuli). The aims of the present study were: 1) to investigate if tasks that can be carried out using different strategies depending on the verbalizability of the material induce a lateralization of the mean cerebral blood flow velocity (mCBFV) in the middle cerebral arteries (MCAs), as monitored by a functional transcranial Doppler (fTCD); 2) to evaluate if these patterns of cerebral activation differ in relation to age, gender and task performance. METHOD: Using TCD bilateral monitoring, we recorded mCBFV variations in 35 male and 35 female healthy, right-handed volunteers, classified as "young" (age range 21-40 years, n=35) or "old"(age range 41-60 years, n=35), performing four different cognitive tasks: encoding and recognition of Geometric Figures (GF), encoding and recall of Object Localization (OL) on a picture, encoding of a verbal Room Description (RD) and Arithmetic Skill (AS). RESULTS: We found a significant right lateralization for the OL recall phase, and a significant left lateralization for RD and AS. When we took into consideration gender, age and performance, there was a strong effect of age on both OL encoding and recall phase, with significant right lateralization in young volunteers not seen in the older ones. No difference in gender was detected. We found a gender×performance interaction for RD, with poor performance females showing significant left lateralization. CONCLUSIONS: According to our findings, hemispheric lateralization during memory encoding is material specific in both men and women, depending on the verbalizability of the material. mCBFV right lateralization during scene encoding and recall appears lost in older people, suggesting that healthy elderly could take advantage of mixed verbal and non-verbal strategies.