Paroxysmal delta waves of awake EEG in childhood adrenoleukodystrophy: Possible indicator of the hematopoietic stem cell therapy (HSCT)

Background: Childhood cerebral type of Adrenoleukodystrophy (CC-ALD) is fatal without hematopoietic stem cell transplantation (HSCT). We consider whether EEGs showing focal paroxysmal delta waves can be a candidate of early detector of the apparent ALD and HSCT therapy.

Methods: Twenty-two male children with ALD (5-16 years; 10.4 ± 2.8) were evaluated. Fourteen children were diagnosed as CC-ALD and the rest 8 were yet asymptomatic both clinical and MRI findings. CC-ALD patients with frontal or occipital MRI main lesions were classified as Types F and O (4 and 10 patients). Asymptomatic patients were classified as Type A whose clinical types had not been known. Awake electroencephalogram was recorded during cognitive tasks and analyzed using fast Fourier transform (FFT). Eight children (1/4 F, 3/10 O and 4/8 A patients) were evaluated pre- and post-HSCT.

Results: FFT analysis revealed the high voltage slow wave characterized by an increased delta band wave power volume (DBPV) in all children. The DBPV of Type F and O patients showed anterior and posterior dominance in 4/4 and 9/10 patients. Dominant DBPV in Type A patients were anterior and posterior in 6/8 and 1/8, respectively. We classified them as Type F' and O'. DBPV decreased in all (8/8) patients after HSCT therapy.

Conclusion: All patients showed paroxysmal delta wave. In symptomatic patients, abnormal delta wave appeared in their corresponding cortical lesions and decreased after therapy. In asymptomatic patients it may be the first sign of the apparent ALD onset and suggesting when to consider HSCT therapy.