Amnesia Research Today is a free monthly online journal that collates and summarizes the latest research about Amnesia, including details on memory loss, causes, treatment, brain injury,.

Internal jugular vein valve incompetence is highly prevalent in transient global amnesia.

Cejas C, Cisneros LF, Lagos R, Zuk C, Ameriso SF

Institute for Neurological Research, FLENI, Neurology Department, Montañeses 2325, C1428AQK, Buenos Aires, Argentina.

BACKGROUND AND PURPOSE: Transient global amnesia (TGA) is the inability to retain new information and to recall past events during a period of minutes or hours. Its etiology is unclear, and flow disturbances in the mesial temporal lobes secondary to venous congestion have been proposed as a potential cause. Ultrasonographic evaluation of the internal jugular vein (IJV) has demonstrated valvular insufficiency in TGA. The prevalence of valvular insufficiency in the IJV in patients with TGA was assessed. Subjects without TGA of similar sex, age, and vascular risk factor profiles served as controls. METHODS: A group of 142 patients with a clinical diagnosis of TGA within 7 days of the clinical event and 40 controls were prospectively evaluated. Venous Doppler examination of both IJVs was performed at baseline and after a manometer-controlled Valsalva maneuver. Valvular insufficiency was diagnosed when there was reflux for >0.8 seconds during the Valsalva maneuver. RESULTS: Valve insufficiency was found in at least one jugular vein in 113 of 142 patients with TGA (79.5%) and in 10 of 40 controls (25.0%), P<0.01. The right side was affected more often than the left side, P<0.01, and 26.8% of the patients had bilateral incompetence. CONCLUSIONS: Patients with TGA have a high prevalence of IJV valve insufficiency. This finding may have pathophysiologic implications. Doppler evaluation of the IJVs with dynamic maneuvers may help in the evaluation of this usually benign condition.

Published 29 December 2009 in Stroke, 41(1): 67-71.
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Articles on Amnesia published 18 December 2009:

A multicentre study on the clinical utility of post-traumatic amnesia duration in predicting global outcome after moderate-severe traumatic brain injury.   J Neurol Neurosurg Psychiatry, 81(1): 87-9.

BACKGROUND: Past research shows that post-traumatic amnesia (PTA) duration is a particularly robust traumatic brain injury (TBI) outcome predictor, but low specificity limits its clinical utility. OBJECTIVES: The current study assessed the relationship between PTA duration and probability thresholds for Glasgow Outcome Scale (GOS) levels. METHODS: Data were prospectively collected in this multicentre observational study. The cohort was a consecutive sample of rehabilitation patients enrolled in ... [Abstract] [Full-text]

Articles on Amnesia published 20 November 2009:

Gamma-aminobutyric acid type A receptor alpha 4 subunit knockout mice are resistant to the amnestic effect of isoflurane.   Anesth Analg, 109(6): 1816-22.

BACKGROUND: General anesthesia produces multiple end points including immobility, hypnosis, sedation, and amnesia. Tonic inhibition via gamma-aminobutyric acid type A receptors (GABA(A)-Rs) may play a role in mediating behavioral end points that are suppressed by low concentrations of anesthetics (e.g., hypnosis and amnesia). GABA(A)-Rs containing the alpha4 subunit are highly concentrated in the hippocampus and thalamus, and when combined with delta subunits they mediate tonic inhibition, ... [Abstract] [Full-text]

Articles on Amnesia published 29 September 2009:

Thalamic contributions to anterograde, retrograde, and implicit memory: a case study.   Clin Neuropsychol, 23(7): 1232-49.

Learning and memory deficits are typically associated with damage or dysfunction of medial temporal lobe structures; however, diencephalic lesions are another common cause of severe and persistent memory deficits. We focus specifically on the thalamus and review the pathological and neuropsychological characteristics of two common causes of such damage: Korsakoff's syndrome and stroke. We then present a patient who had sustained bilateral medial thalamic infarctions that affected the medial ... [Abstract] [Full-text]

Articles on Amnesia published 18 September 2009:

White matter hyperintensities and medial temporal lobe atrophy in clinical subtypes of mild cognitive impairment: the DESCRIPA study.   J Neurol Neurosurg Psychiatry, 80(10): 1069-74.

BACKGROUND: Clinical subtypes of mild cognitive impairment (MCI) may represent different underlying aetiologies. METHODS: This European, multicentre, memory clinic based study (DESCRIPA) of non-demented subjects investigated whether MCI subtypes have different brain correlates on MRI and whether the relation between subtypes and brain pathology is modified by age. Using visual rating scales, medial temporal lobe atrophy (MTA) (0-4) and white matter hyperintensities (WMH) (0-30) were assessed. ... [Abstract] [Full-text]

Articles on Amnesia published 9 September 2009:

Conversion of amyloid positive and negative MCI to AD over 3 years: an 11C-PIB PET study.   Neurology, 73(10): 754-60.

BACKGROUND: Patients with amnestic mild cognitive impairment (MCI) represent an important clinical group as they are at increased risk of developing Alzheimer disease (AD). (11)C-PIB PET is an in vivo marker of brain amyloid load. OBJECTIVE: To assess the rates of conversion of MCI to AD during a 3-year follow-up period and to compare levels of amyloid deposition between MCI converters and nonconverters. METHODS: Thirty-one subjects with MCI with baseline (11)C-PIB PET, MRI, and ... [Abstract] [Full-text]

Articles on Amnesia published 3 September 2009:

Impaired category fluency in medial temporal lobe amnesia: the role of episodic memory.   J Neurosci, 29(35): 10900-8.

Memory tasks are often classified as semantic or episodic, but recent research shows that these types of memory are highly interactive. Category fluency, for example, is generally considered to reflect retrieval from semantic memory, but behavioral evidence suggests that episodic memory is also involved: participants frequently draw on autobiographical experiences while generating exemplars of certain categories. Neuroimaging studies accordingly have reported increased medial temporal lobe ... [Abstract] [Full-text]

Articles on Amnesia published 25 August 2009:

Implicit false memory in the DRM paradigm: effects of amnesia, encoding instructions, and encoding duration.   Neuropsychology, 23(5): 635-48.

Recent studies with the Deese/Roediger-McDermott (Deese 1959; Roediger & McDermott, 1995) paradigm have revealed that amnesic patients do not only show impaired veridical memory, but also diminished false memory for semantically related lure words. Due to the typically used explicit retrieval instructions, however, this finding may reflect problems at encoding, at recollection, or both. Therefore, the present experiments examined implicit as well as explicit false memory in patients ... [Abstract] [Full-text]

Delaying interference enhances memory consolidation in amnesic patients.   Neuropsychology, 23(5): 627-34.

Some patients with amnesia are able to retain new information for much longer than expected when the time that follows new learning is devoid of further stimuli. Animal work shows that the absence or delaying of interference improves long-term memory consolidation. Our study suggests that this is also true for at least some patients with amnesia. Retention of new verbal material was significantly higher in a sample of patients with amnesia (N = 12) when interference occurred at the end of a ... [Abstract] [Full-text]

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