Clinical Findings in Isolated Bulbar Amyotrophic Lateral Sclerosis


  • Omar Jawdat University of Kansas Medical Center
  • Duaa Jabari University of Kansas Medical Center
  • Jeffrey Statland University of Kansas Medical Center
  • Andrew Heim University of Kansas Medical Center
  • Richard Barohn University of Missouri



Amyotrophic Lateral Sclerosis, ALS, isolated, bulbar


Background: Isolated bulbar amyotrophic lateral sclerosis (IBALS) is a regional variant of amyotrophic lateral sclerosis (ALS) with weakness restricted to the bulbar muscles for at least 2 years, and slower progression than generalized ALS. Bulbar-onset generalized ALS, by contrast, typically has a more rapid progression than limb-onset ALS.
Objective: To characterize patients with IBALS and compare them to patients with isolated bulbar disease at presentation who progress to generalized ALS.
Methods: We performed a retrospective chart review of patients seen in our ALS specialty clinic at the University of Kansas Medical Center between 2001-2011.
Results: Of 543 patients seen in the ALS clinic, 150 presented with bulbar symptoms at disease onset: 28 (18.7%) had bulbar signs and no evidence of extremity involvement on exam or electrodiagnostic testing at their initial visit; and 14 (9.3%) had weakness restricted to the bulbar muscles after 2 years of follow up (IBALS). IBALS patients were 57.1% male, with a mean age of symptom onset of 60.8 years (range 39-77 years). The mean disease duration was 3.1 years (range of 2-8 years), with 50% mortality at a mean follow up of 3.5 years. Minimal denervation changes were seen in at least one limb in 6 subjects (42.9%). Other clinical features included: 4 subjects (28.6%) had cognitive impairment, 4 (28.6%) had pseudo-bulbar affect, and 5 subjects (35.7%) had impaired eye movements on smooth pursuit.
Conclusion: Isolatred bulbar ALS IBALS is an identifiable restricted regional ALS pattern if there is no clinical limb weakness 2 years after symptom onset. It may have a slower progression from typical ALS. The biologic factors that account for the IBALS restricted pattern are unknown.


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(1) Katz JS, Wolfe GI, Andersson PB, Barohn RJ et al. Brachial amyotrophic diplegia: a slowly progressive motor neuron disorder. Neurology. 1999;53:1071-1076
(2) Dimachkie MM et al. Leg amyotrophic diplegia
(3) Jawdat O, Statland JM, Barohn RJ, Katz JS, Dimachkie MM. Amyotrophic Lateral Sclerosis Regional Variants (Brachial Amyotrophic Diplegia, Leg Amyotrophic Diplegia, and Isolated Bulbar Amyotrophic Lateral Sclerosis). Neurol Clin 2015; 33, 775-85.
(4) del Aguila MA, Longstreth WT,Jr, McGuire V, Koepsell TD, van Belle G. Prognosis in amyotrophic lateral sclerosis: a population-based study. Neurology 2003 Mar 11;60(5):813-819.
(5) Traxinger K, Kelly C, Johnson BA, Lyles RH, Glass JD. Prognosis and epidemiology of amyotrophic lateral sclerosis: Analysis of a clinic population, 1997-2011. Neurol Clin Pract 2013 Aug;3(4):313-320.
(6) Turner MR, Bakker M, Sham P, Shaw CE, Leigh PN, Al-Chalabi A. Prognostic modelling of therapeutic interventions in amyotrophic lateral sclerosis. Amyotroph Lateral Scler Other Motor Neuron Disord 2002 Mar;3(1):15-21.
(7) Chio A, Calvo A, Moglia C, Mazzini L, Mora G, PARALS study group. Phenotypic heterogeneity of amyotrophic lateral sclerosis: a population based study. J Neurol Neurosurg Psychiatry 2011 Jul;82(7):740-746.
(8) Zoccolella S, Beghi E, Palagano G, Fraddosio A, Guerra V, Samarelli V, et al. Predictors of long survival in amyotrophic lateral sclerosis: a population-based study. J Neurol Sci 2008 May 15;268(1-2):28-32.




How to Cite

Jawdat, O., Jabari, D., Statland, J., Heim, A., & Barohn, R. (2020). Clinical Findings in Isolated Bulbar Amyotrophic Lateral Sclerosis. RRNMF Neuromuscular Journal, 1(4), 11-13.



New Discoveries/New Stuff (Original Research)