Benign focal amyotrophy: a longitudinal study (13-15 years) in 3 cases

Area of Science:

• Neurology
• Neurophysiology
• Muscle Diseases

Background:

• Hirayama disease, also known as benign focal amyotrophy (BFA), is a rare motor neuron disorder.
• Previous studies have described its occurrence in various countries, characterized by specific clinical and neurophysiological patterns.

Observation:

• This report details three young Italian patients (two male, one female) diagnosed with BFA.
• Clinical and neurophysiological follow-up, including muscle biopsies in two patients, spanned 13-15 years.
• The study confirms the presence of Hirayama disease in Italy, consistent with international descriptions.

Findings:

• BFA exhibits a mild progression of muscle atrophy over the initial two years, followed by a period of stabilization.
• Neurophysiological studies revealed no significant differences between BFA and other forms of motor neuron disease, apart from its segmental nature.
• The findings support the hypothesis that BFA may represent a segmental transitional form of amyotrophic lateral sclerosis (ALS).

Implications:

• The confirmation of Hirayama disease in Italy expands its known geographical distribution.
• Understanding the 'delaying' factor in BFA's progression could offer insights into motor neuron disease pathogenesis.
• Further research into the neurophysiological characteristics may aid in differentiating BFA from other motor neuron disorders.