Hippocampal Volume and Memory Functions in Aneurysmal Subarachnoid Hemorrhage

Long-term or even permanent neuropsychological impairments are frequently observed after aneurysmal subarachnoid hemorrhages (aSAH). Among the most common impairments after aSAH are memory deficits. Volumetric MRI studies suggest an association of memory dysfunctions with temporal atrophy, especially of the hippocampus. In a previous study, 77 patients with good or moderate clinical outcome after aSAH were examined one year after discharge (Bendel et al., 2006). Temporomesial atrophy was detected without direct brain damage, e.g. by secondary ischemia. Due to the effects of complex cognitive impairments on the quality of life and participation in social and professional life, this relationship will be examined in more detail in the planned study. Specifically, we will investigate to what extent the frequently observed discrepancy between severe memory impairment and normal structural imaging results (no focal lesions in temporomesial areas) is due to hippocampal atrophy. In contrast to Bender and colleagues, this question will be investigated in the acute phase of the disease, immediately after admission to inpatient neurological rehabilitation.

Over a period of 24 months, 29 neurological rehabilitation patients with aSAH (Hunt & Hess grade I and II) are going to be included. Within the first week (day 1 to 7) after study enrollment, a native MRI examination (without contrast agent) is performed, in which a high-resolution 3D-MPRAGE sequence (T1 weighting) is measured in the sagittal plane. After checking the data quality of the 3D-MPRAGE sequence, especially with regard to its suitability for hippocampal volume determination, a comprehensive neuropsychological examination is performed, in which specific memory and attentional functions are tested.

Inclusion criteria

• neurological rehabilitation patients in phase B - D
• at minimum eight weeks after disease onset
• aneurysmal subarachnoid hemorrhage (Hunt & Hess grade I or II)
• written consent from the patient's legal representative
• exclusion of pregnancy

Exclusion criteria

• insufficient cardiorespiratory stability
• previous brain damage
• mental disorders (dementia, depression)
• colonization with multi-resistant pathogens
• MRI contraindications
• claustrophobia
• weight > 120 kg