F. Hirashima

DISSOCIATED SMALL HAND MUSCLE ATROPHY IN AMYOTROPHIC LATERAL SCLEROSIS: FREQUENCY, EXTENT, AND SPECIFICITY

Previous studies suggest that in amyotrophic lateral sclerosis (ALS) the abductor pollicis brevis (APB) and first dorsal interosseous (FDI) are more severely involved than abductor digiti minimi (ADM). To elucidate the pattern, frequency, extent, and specificity of such dissociated muscle atrophy in ALS, compound muscle action potentials recorded from APB, FDI, and ADM were analyzed in 77 ALS patients, 171 normal controls, and 196 disease controls. Compared with normal controls, ALS patients had a reduced APB/ADM amplitude ratio (P < 0.001) and FDI/ADM ratio (P < 0.001), whereas patients with other anterior horn diseases showed similar APB/ADM and FDI/ADM ratios to normal values. Decreased APB/ADM ratio was found in 41% of ALS patients, 5% of normal controls, and 4% of disease controls. Prominent muscle atrophy in APB and FDI, with relatively preserved ADM, appears to be specific to ALS. Dissociated hand muscle atrophy presumably reflects part of the pathophysiology and supports the diagnosis of ALS. Muscle Nerve, 2008

MRI findings of inferior olives in palatal myoclonus.

SummaryFour patients with palatal myoclonus (PM) were studied with magnetic resonance imaging (MRI). Increased signal intensity and bilateral enlargement of the inferior olives were recognized in two patients with bilateral PM, pontine haemorrhage and neuro-Behçet disease, and a similar olivary change on the contralateral side was noted in a case of pontine infarction with unilateral PM. These findings were consistent with the pathology. The changes were more obvious in proton density-weighted images than in T2-weighted images, which thus differ from the changes in common gliosis. The other patient with the syndrome of PM and progressive ataxia did not show any olivary change. These changes on MRI are considered to indicate pseudo-hypertrophy of the inferior olives, although this is not consistently shown by the imaging method.

Utility of trapezius EMG for diagnosis of amyotrophic lateral sclerosis.

Needle electromyography (EMG) of the tongue is traditionally used as a key to the diagnosis of amyotrophic lateral sclerosis (ALS), although relaxation of the tongue is often difficult to achieve. Recently, frequent abnormalities in the EMGs of the sternocleidomastoid (SCM) and upper trapezius muscles in ALS have been reported. To elucidate the diagnostic utility of these muscles we performed a multicenter prospective study to examine EMGs of the tongue (genioglossus), SCM, and trapezius in 104 ALS or suspected ALS patients. We also examined EMGs of the SCM and trapezius in 32 cervical spondylosis (CS) patients. We mainly evaluated fibrillation potentials/positive sharp waves (Fib/PSWs) and fasciculation potentials. Complete relaxation was achieved in 85% of ALS patients in the trapezius, but in only 6% of patients in the tongue. Fib/PSWs were observed in 8%, 13%, and 45% of ALS patients in the tongue, SCM, and trapezius, respectively, whereas fasciculation potentials were observed in 1%, 7%, and 39%, respectively. Abnormal spontaneous activity of any type was found in 9%, 17%, and 63% of patients, respectively. The high frequency of abnormal spontaneous activity in the trapezius was similar among the different diagnostic categories, and even 72% of clinically suspected ALS (progressive muscular atrophy) patients showed them in their trapezius. We did not observe Fib/PSWs or fasciculation potentials in any of our CS patients, thus these findings have excellent specificity. Tongue EMG added little utility over the clinical sign of tongue atrophy. Abnormal spontaneous activity in the trapezius would be more useful for the early diagnosis of ALS. Muscle Nerve 39: 63–70, 2009

Sympathetic skin response in Parkinson's disease

Sudomotor function in 83 patients with Parkinsons disease (PD) was evaluated using the sympathetic skin response (SSR) and sweat response to intradermal acetylcholine (ACh) injection. The incidence of abnormal SSRs (36.1%) increased, and the size of the response decrease with the severity of the illness. Neither the incidence of abnormal SSRs nor the amplitudes of the responses were influenced by levodopa or an anticholinergic agent. The SSR therefore can be used to evaluate the sudomotor efferent pathway in PD patients. In all the patients who had no SSR response, the local sweat response to ACh showed a reduced number of excitable sweat glands and low sweat volume. One patient, whose local sweat response to ACh was markedly impaired, had unmyelinated and acetylcholinesterase‐positive fiber densities that were in the normal range in his biopsied sural nerve. The abnormal sweat response to ACh is considered to reflect the dysfunction of postganglionic sympathetic fibers in PD patients.

Idiopathic palatal myoclonus

Two cases with idiopathic palatal myoclonus without other neurological deficits were described. They did not have any other neurological deficits other than myoclonus of branchial muscles. In these cases, the myoclonus disappeared during natural or induced sleep. In Case 1, the myoclonus ceased transiently when the patient was calculating or receiving an injection. In Case 2, the myoclonus disappeared with intravenous injection of saline as a placebo. Detailed examinations, including brain CT, MRI and multiple evoked potentials, showed normal results. The myoclonus in Case 2 disappeared after we had explained that her disease was benign. Since the clinical features and laboratory data in idiopathic palatal myoclonus are quite different from those in palatal myoclonus with other neurological deficits, idiopathic palatal myoclonus is considered to be a separate syndrome. Invasive examinations or excessive medications should be avoided because of its benign prognosis.

Increased central motor tract excitability in Creutzfeldt-Jakob disease

Central motor tract excitability was examined in 2 patients with Creutzfeldt-Jakob disease (CJD) and 8 normal subjects by measuring change in the motor evoked potential (MEP) by transcranial magnetic stimulation of the motor cortex after peripheral nerve stimulation. Conditioning stimulation of the median nerve at the wrist greatly increased MEP size (500-1700%) as compared to the size for normal subjects (140-380%) at conditioning-test (C-T) intervals of 30-60 msec for patient 1 and 40-70 msec for patient 2. Moreover, stimulation of the contralateral median nerve at the wrist and of the second and third digits also increased MEP size in the CJD patients; whereas, there was no increase in size in the normals. The time courses of abnormal MEP potentiation were very consistent with the course of the corresponding C reflex. One of the CJD patients had a normal size SEP, and neither patient showed hyperexcitability in SEP-recovery at C-T intervals of 20-60 msec at which there was marked MEP potentiation. These results indicate that there was hyperexcitability of the central motor tract in the CJD patients after the conditioning of muscle and cutaneous peripheral afferents and that it extended to the ipsilateral cortex on the conditioning side as well.

S35-4 EMGs in ALS

Upper motor neuron (UMN) signs are frequently difficult to detect in patients with ALS. Transcranial magnetic stimulation (TMS) and MRI techniques offer options to solve this task. The diagnostic yield of conventional single pulse TMS in ALS patients without clinical UMN signs is low. Short interval paired pulse TMS looking for reduction of intracortical inhibition has proven more successful although it has not been widely used. Ipsilateral MEPs having a similar pathomechanism as mirror movements seem to be a sensitive tool and should be further explored. The triple stimulation technique (Magistris et al, 1996) seems to have the greatest potential to detect UMN involvement in the absence of clinical signs and deserves a wider distribution. These technique has also been shown to be able to detect UMN involvement in a significant number of patients with Multiple System Atrophy. Another hope is MRI. Conventional cranial MRI occasionally reveals signal changes in the area of the corticospinal tract although these changes are seen rarely and may also be present in healthy persons. Diffusion tensor imaging can detect structural changes in fibre tracts such as the corticospinal tract. It shows significant changes in groups of ALS patients and also in some individuals. It is unproven, however, that it can detect changes in individual patients without clinical upper motor neuron signs. This holds also true for other MRI techniques such as spectroscopy. Voxel based morphometry shows cortical atrophy beyond the motor areas in comparisons between ALS patients and healthy controls. It can, however, not be used on an individual level. High field techniques (7 Tesla) and fMRI may be promising. Detection of UMN signs in ALS can still be a demanding task. Since it is of greatest diagnostic importance further research in this field is required.

80. Utility of EMG examinations of the tongue (genioglossus), sternocleidomastoideus (SCM), and upper trapezius muscles for the diagnosis of amyotrophic lateral sclerosis (ALS): A multicenter prospective study

occipital to frontal region exist in both the EEG data. In general, Information flow patterns in multichannel alpha activities of normal persons calculated by MDC analysis have left-right symmetry and show a common directional property which shows information flow from occipital to frontal region. Analyzing other EEG data of the same subject at rest with eyes closed, we obtained the result that bidirectional information flows between occipital and frontal region existed and left-right asymmetrical information flow pattern was shown. In contrast, the analysis of the photic driving data does not shows bidirectional information flows between occipital and frontal region.