Writing errors in ALS related to loss of neuronal integrity in the anterior cingulate gyrus

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by loss of motor neuron and various cognitive deficits including writing errors. 11C-flumazenil (FMZ), the positron emission tomography (PET) GABAA receptor ligand, is a marker of cortical dysfunction. The objective of this study was to investigate the relationship between cognitive deficits and loss of neuronal integrity in ALS patients using 11C-FMZ PET. Ten patients with ALS underwent both neuropsychological tests and 11C-FMZ-PET. The binding potential (BP) of FMZ was calculated from 11C-FMZ PET images. There were no significant correlations between the BP and most test scores except for the writing error index (WEI), which was measured by the modified Western Aphasia Battery - VB (WAB-IVB) test. The severity of writing error was associated with loss of neuronal integrity in the bilateral anterior cingulate gyrus with mild right predominance (n = 9; x = 4 mm, y = 36 mm, z = 4 mm, Z = 5.1). The results showed that writing errors in our patients with ALS were related to dysfunction in the anterior cingulate gyrus.