Evaluation of the relationship between clinical findings and F responses and diffusion tensor tractography in patients with amyotrophic lateral sclerosis

Abstract

Purpose: The aim of this study is to show whether radiologically diffusion tractography imaging (DTI) and electrophysiologically F responses methods support clinical examination in Amyotrophic Lateral Sclerosis (ALS). It is to determine the relationships between these two methods.
 Materials and Methods: Patients with a definite diagnosis of ALS according to the Revised-El Escorial and Awaji criteria at any stage of the disease, who applied to the Electromyography (EMG) laboratory of the Neurology Clinic of Istanbul University Cerrahpaşa, Cerrahpaşa Medical Faculty, prospectively and cross-sectionally, were included in the study. The revised ALS functional rating scale (ALSFRS-R) was scored. Electrophysiological studies included routine nerve conduction studies, F responses and needle EMG. In radiological examinations, diffusion tractography imaging (DTI) maps were obtained in brain and cervical Magnetic Resonance Imaging (MRI) and diffusivity and fractional anisotropy (FA) values were compared. 
 Results: The mean age of the 12 volunteer patients included in the study was 55.92±9.68 (43-72), and consisted of 4 female and 8 male individuals. The mean ALSFRS-R score was 35.75±7.86 (24-46). MRI was performed in 11 of the patients, spinal imaging could not be performed in one patient. The mean age of the 11 patients who were imaging was 56.4±9.8 years and the disease duration was 2.7±1.9 years. Low values of DTI-FA were found to be associated with poor respiratory and speech scores as assessed by linear regression analysis. Repeater F responses in the ulnar nerves were also associated with a high ALSFRS-R score.
 Conclusion: In our study, we observed that low values of DTI-FA were associated with poor respiratory and speech scores. Showing the correlation of low FA with a vital function such as respiration may indicate that this technique will be helpful in the prognosis and progression of the disease. The increase of repeater F responses in the ulnar nerves in those with high ALSFRS-R scores suggests that it is worth investigating whether ALS can be used in differentiating from other anterior horn diseases. The results of this study suggest that DTI-FA, which is an advanced radiological evaluation, and repeater F responses as an electrophysiological method may support early diagnosis in ALS.