**7. Results**

#### **7.1. Demographics**

A total of eighty-eight (88) subjects (45 males and 43 females) gave informed consent. The subjects were divided into four test groups.

	- **a.** 5 subjects with point mutation in exon 4, codon 100, GAA to GGA, Glu to Gly) glu100gly;
	- **b.** 5 subjects with point mutation in exon 4, codon 113, ATT to ACT, Ile to Thr) ile113thr;
	- **c.** 5 subjects with point mutation in exon 5; codon 148, GTA to GGA, Val to Gly) val148gly;
	- **d.** 5 subjects with point mutation in exon 5, codon 148, GTA to GGA, Val to Ile) val148ile.


**Table 1.** Thenar (APB) motor unit number estimates (MUNE number represents mean MUNE).

**4.** 12 sporadic symptomatic MND patients (positive controls).

There was no statistically significant difference in age distribution between these groups, with a range of 16 to 73 years of age.

#### **7.2. Motor units in asymptomatic FALS (SOD1) carriers**

reproducible, time efficient and quantitative measure for monitoring disease progression in MND. (Hoagland et al., 1997). This would be surprising, given that in a slowly progressive denervating process, patients with substantial chronic denervation could maintain normal muscle twitch tension until loss of about 70-80% of motor units occurs. (McComas, 1971).

The methods used to quantify maximal voluntary isometric contraction have included an electronic strain-gauge tensiometer and a hand-held Jamar hydraulic dynamometer. In this study, maximum bilateral isometric grip strength was obtained using the Jamar hydraulic dynamometer to determine whether this correlated with the number of functional motor neurones in the thenar group of muscles, as measured by MUNE. Standardised (middle handle) positioning and instructions were given to all subjects. Handgrip force was measured with subjects in the sitting position and with the arm flexed at 90 degrees. Two trials were performed on each hand, and the best result used for analysis. This method was used as previous studies of grip strength reliability showed that there was no significant difference in reliability between one attempt, the mean score of two or three attempts, or the highest score

Clinical neurological examination was performed, with power of thumb abduction, finger flexion and finger abduction measured according to the Medical Research Council (MRC)

Felice showed that in twenty one MND patients, changes in thenar MUNE was the most sensitive outcome measure for following disease progression, when compared to other quantitative tests, such as CMAP, isometric grip strength, forced vital capacity and Medical

A total of eighty-eight (88) subjects (45 males and 43 females) gave informed consent. The

**a.** 5 subjects with point mutation in exon 4, codon 100, GAA to GGA, Glu to Gly) –

**b.** 5 subjects with point mutation in exon 4, codon 113, ATT to ACT, Ile to Thr) – ile113thr; **c.** 5 subjects with point mutation in exon 5; codon 148, GTA to GGA, Val to Gly) –

**d.** 5 subjects with point mutation in exon 5, codon 148, GTA to GGA, Val to Ile) val148ile.

of three attempts. (Hamilton et al., 1994).

200 Current Advances in Amyotrophic Lateral Sclerosis

**7. Results**

**7.1. Demographics**

**1.** 24 population controls;

glu100gly;

val148gly;

grading system and compared to thenar (APB) MUNE.

Research Council manual muscle testing. (Felice, 1997).

subjects were divided into four test groups.

**2.** 32 SOD1 negative (normal) family controls;

**3.** 20 asymptomatic (pre-clinical) SOD1 mutation carriers (test group),

For the initial part of the study, the baseline MUNE results were grouped together and the means of the groups were compared. The initial aim of the study was to determine if MND was due to a slow gradual attrition of motor neurones over time. If this were the case, the group of asymptomatic SOD1 mutation carriers, would be expected to have a reduced number of motor units, indicating the presence of pre-clinical motor neurone loss. Motor unit estimates in the group of asymptomatic SOD1 mutation carriers were compared to age and sex matched family controls without the SOD1 mutation, and sporadic (non-SOD1) MND patients. To determine whether groups had different numbers of motor units, an unpaired t-test was used. Statistical significance was accepted at a p-value of <0.05.

The numbers of motor units in the groups of population controls, SOD1 negative family controls and asymptomatic SOD1 mutation carriers were similar. In population controls the mean thenar MUNE was 148 with a range of 115 - 254, in SOD1 negative family controls was 138 with a range of 106 - 198 and in asymptomatic SOD1 mutation carriers, 144 with a range of 109 - 199. There was no detectable difference in the mean number of thenar motor units in the group of asymptomatic SOD1 mutation carriers compared to the group of SOD1 negative family controls (thenar p>0.46), or population controls (thenar p>0.70) (Table 1 and Figure 6).

In population controls the mean EDB MUNE was 138 with a range of 119 - 169, in SOD1 negative family controls was 134 with a range of 107 - 180 and in asymptomatic SOD1 mutation carriers, 136 with a range of 111 - 187.

Once again, there was no detectable difference in the mean number of EBD motor units in the group of asymptomatic SOD1 mutation carriers compared to the group of SOD1 negative family controls (EDB p>0.95), or population controls (EDB p>0.50) (Table 2 and Figure 7).

Study Groups

digitorum brevis (EDB) MUNE tests repeated every 3-6 months, depending on patient availability. The difference between MUNE results from the first and second study, and if possible, first and third studies were divided by the MUNE of the first study, and expressed as a percentage change. The results were analysed using Pearson and Spearman correlation

**Figure 7.** Baseline EDB MUNE subdivided into study groups (The lower boundary of the box is the 25th percentile, and the upper border is the 75th percentile of MUNE. The horizontal line inside the box represents the median MUNE. The

SOD1 Mut Carriers

Population Controls

EDB MUNE

200

150

100

50

0

Study Groups

SOD1 Neg Controls

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Sporadic MND

The test-retest correlation of thenar MUNE in asymptomatic subjects was high with a Pearson correlation coefficient of 0.93. The mean difference between MUNE results on separate

**Number of Cases Mean MUNE**

**Table 3.** Reproducibility of mean thenar (APB) motor unit number estimates in asymptomatic subjects on separate

For EDB MUNE, the Pearson correlation coefficient was also high, 0.88, with a mean difference between MUNE results on separate occasions on the same individual of +/- 4.6%, with a range

occasions on the same individual was +/- 3.6%, with a range of 0-11.7% (Table 3).

whispers represent the largest and smallest observed values, i.e. the range). Data is shown in Table 2.

Thenar 1 88 145.7 Thenar 2 69 140.1 Thenar 3 33 140.0 **Thenar Change Range (0 - 11.7%) 3.6%**

coefficients.

reviews over a one-year period.

**Figure 6.** Baseline thenar (APB) MUNE subdivided into study groups (The lower boundary of the box is the 25th per‐ centile, and the upper border is the 75th percentile of MUNE. The horizontal line inside the box represents the median MUNE. The whispers represent the largest and smallest observed values, i.e. the range). Data is shown in Table 1.


**Table 2.** EDB motor unit number estimates (MUNE number represents mean MUNE).

Symptomatic sporadic MND subjects showed a definite loss of motor units with fewer motor units compared to all other groups (p<0001) with a mean thenar MUNE of 45 with a range of 5 - 84 and a mean EDB MUNE of 70 with a range of 8 - 82 (Tables 1 and 2).

There was no cross over between thenar and EDB MUNE results in symptomatic and asymp‐ tomatic subjects.

#### **7.3. Reproducibility of MUNE technique**

To assess the test-retest reproducibility of the technique, 69 of the 88 SOD1 family members and population controls were followed over a 1-year period, with thenar and extensor

**Figure 7.** Baseline EDB MUNE subdivided into study groups (The lower boundary of the box is the 25th percentile, and the upper border is the 75th percentile of MUNE. The horizontal line inside the box represents the median MUNE. The whispers represent the largest and smallest observed values, i.e. the range). Data is shown in Table 2.

digitorum brevis (EDB) MUNE tests repeated every 3-6 months, depending on patient availability. The difference between MUNE results from the first and second study, and if possible, first and third studies were divided by the MUNE of the first study, and expressed as a percentage change. The results were analysed using Pearson and Spearman correlation coefficients.

The test-retest correlation of thenar MUNE in asymptomatic subjects was high with a Pearson correlation coefficient of 0.93. The mean difference between MUNE results on separate occasions on the same individual was +/- 3.6%, with a range of 0-11.7% (Table 3).


Symptomatic sporadic MND subjects showed a definite loss of motor units with fewer motor units compared to all other groups (p<0001) with a mean thenar MUNE of 45 with a range of

Study Groups

SOD1 Mut Carriers

**Figure 6.** Baseline thenar (APB) MUNE subdivided into study groups (The lower boundary of the box is the 25th per‐ centile, and the upper border is the 75th percentile of MUNE. The horizontal line inside the box represents the median MUNE. The whispers represent the largest and smallest observed values, i.e. the range). Data is shown in Table 1.

Population Controls

APB MUNE

250

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200

150

100

50

0

SOD1 Neg Controls

Sporadic MND

**Extensor Digitorum Brevis**

**Cases MUNE (Range)**

There was no cross over between thenar and EDB MUNE results in symptomatic and asymp‐

To assess the test-retest reproducibility of the technique, 69 of the 88 SOD1 family members and population controls were followed over a 1-year period, with thenar and extensor

5 - 84 and a mean EDB MUNE of 70 with a range of 8 - 82 (Tables 1 and 2).

**Table 2.** EDB motor unit number estimates (MUNE number represents mean MUNE).

**Population Controls** 13 138 (119-169) **SOD1 Negative Family Controls** 30 134 (107-180) **SOD1 Mutation Carriers** 14 136 (111-187)

**Sporadic MND patients** 9 70 (8-82)

tomatic subjects.

**7.3. Reproducibility of MUNE technique**

**Table 3.** Reproducibility of mean thenar (APB) motor unit number estimates in asymptomatic subjects on separate reviews over a one-year period.

For EDB MUNE, the Pearson correlation coefficient was also high, 0.88, with a mean difference between MUNE results on separate occasions on the same individual of +/- 4.6%, with a range of 0-15.7%. The test-retest correlation was high with a Pearson correlation coefficient of 0.91, when groups were broken down into the different study groups.

#### **7.4. Maximal voluntary isometric contraction**

Maximal voluntary isometric contraction (MVIC), using the Jamar hand dynamometer was used to measure isometric grip strength to determine whether this correlated with the number of functional motor neurones in the thenar group of muscles as measured by MUNE. Isometric grip strength tests, thenar MUNE and MRC power were performed on 69 asymptomatic subjects twice within a 3-6 month period to assess the test-retest reproducibility of this technique. Pearson correlation coefficients between study 1 and study 2 of right hand grip strength was 0.941, left hand grip strength 0.910 and thenar MUNE results 0.937. These results indicate that the reproducibility of these techniques was high.

Right hand grip strength correlated with left hand grip strength, with Pearson correlation coefficients of 0.959 and Spearman correlation coefficients of 0.956 Two-way analyses of variance showed a no significant difference between the right and left hands (Figure 8). There was no correlation between right grip strength and right thenar motor unit number, with Pearson correlation coefficients of 0.483 and Spearman correlation coefficient of 0.34 (Figure 9).

until sudden, rapid multi-focal cell death of motor neurones occurs, corresponding with the

**Figure 9.** Scatter graph showing the lack of correlation between right handgrip and right thenar (APB) MUNE

Average APB MUNE 0 50 100 150 200 250 300

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During the course of the study, 5 of the SOD1 mutation carriers developed leg weakness. A significant fall in motor unit number was detected in these 5 SOD1 mutation carriers, were there was a detectable reduction of motor units, 4-10 months prior to the onset of weakness and the diagnosis of familial ALS being made. There was no detectable loss of motor units in the other 15 SOD1 mutation carriers or in the group of SOD1 mutation negative relatives,

There was further motor unit loss as weakness progressed, at which point the diagnosis of

A 43-year-old sister of case 1. She had the same strong family history of ALS, with a point mutation in SOD1 gene at val148gly. Her pedigree is shown in Figure 10. She was asympto‐ matic at the time of recruitment with a normal neurological examination, and no evidence of

51% loss of motor units, 4 months prior to onset of weakness in Case 1 37% loss of motor units, 10 months prior to onset of weakness in Case 2 28% loss of motor units, 6 months prior to onset of weakness in Case 3 46% loss of motor units, 6 months prior to onset of weakness in Case 4 68% loss of motor units, 8 months prior to onset of weakness in Case 5

development of symptoms.

Average Right Handgrip (lb)

150

100

50

0

during the study period.

MND was confirmed.

*7.5.1. Case study 1*

In individual cases, there was:

Average Left Handgrip (lb)

**Figure 8.** Graph showing the correlation between right and left handgrip

#### **7.5. Detection of pre-symptomatic motor neurone loss in SOD1 mutation carriers**

The MUNE results, after validating their reproducibility, were used as a baseline to follow the number of motor units over time in individual pre-symptomatic SOD1 mutation carriers over the next 2-5 years, to determine whether pattern of motor neurone loss is either a slow attrition of motor neurones over time or whether normal numbers of motor neurones are maintained

**Figure 9.** Scatter graph showing the lack of correlation between right handgrip and right thenar (APB) MUNE

until sudden, rapid multi-focal cell death of motor neurones occurs, corresponding with the development of symptoms.

During the course of the study, 5 of the SOD1 mutation carriers developed leg weakness. A significant fall in motor unit number was detected in these 5 SOD1 mutation carriers, were there was a detectable reduction of motor units, 4-10 months prior to the onset of weakness and the diagnosis of familial ALS being made. There was no detectable loss of motor units in the other 15 SOD1 mutation carriers or in the group of SOD1 mutation negative relatives, during the study period.

In individual cases, there was:

of 0-15.7%. The test-retest correlation was high with a Pearson correlation coefficient of 0.91,

Maximal voluntary isometric contraction (MVIC), using the Jamar hand dynamometer was used to measure isometric grip strength to determine whether this correlated with the number of functional motor neurones in the thenar group of muscles as measured by MUNE. Isometric grip strength tests, thenar MUNE and MRC power were performed on 69 asymptomatic subjects twice within a 3-6 month period to assess the test-retest reproducibility of this technique. Pearson correlation coefficients between study 1 and study 2 of right hand grip strength was 0.941, left hand grip strength 0.910 and thenar MUNE results 0.937. These results

Right hand grip strength correlated with left hand grip strength, with Pearson correlation coefficients of 0.959 and Spearman correlation coefficients of 0.956 Two-way analyses of variance showed a no significant difference between the right and left hands (Figure 8). There was no correlation between right grip strength and right thenar motor unit number, with Pearson correlation coefficients of 0.483 and Spearman correlation coefficient of 0.34 (Figure 9).

> Average Left Handgrip (lb) 0 50 100 150

**7.5. Detection of pre-symptomatic motor neurone loss in SOD1 mutation carriers**

The MUNE results, after validating their reproducibility, were used as a baseline to follow the number of motor units over time in individual pre-symptomatic SOD1 mutation carriers over the next 2-5 years, to determine whether pattern of motor neurone loss is either a slow attrition of motor neurones over time or whether normal numbers of motor neurones are maintained

when groups were broken down into the different study groups.

indicate that the reproducibility of these techniques was high.

**7.4. Maximal voluntary isometric contraction**

204 Current Advances in Amyotrophic Lateral Sclerosis

Average Right Handgrip (lb)

150

100

50

0

**Figure 8.** Graph showing the correlation between right and left handgrip

51% loss of motor units, 4 months prior to onset of weakness in Case 1

37% loss of motor units, 10 months prior to onset of weakness in Case 2

28% loss of motor units, 6 months prior to onset of weakness in Case 3

46% loss of motor units, 6 months prior to onset of weakness in Case 4

68% loss of motor units, 8 months prior to onset of weakness in Case 5

There was further motor unit loss as weakness progressed, at which point the diagnosis of MND was confirmed.

#### *7.5.1. Case study 1*

A 43-year-old sister of case 1. She had the same strong family history of ALS, with a point mutation in SOD1 gene at val148gly. Her pedigree is shown in Figure 10. She was asympto‐ matic at the time of recruitment with a normal neurological examination, and no evidence of

**Figure 10.** Pedigree of cases 1, 2 and 3

wasting, weakness or fasciculation. Her right and left thenar MUNE's remained stable for the first 2½ years of the study at around 115-120 motor units. Progress MUNE results are shown in Table 4 and Figures 11.

*7.5.2. Case study 2*

**weakness 1st detected**

in Table 5.

A 57-year-old man with a strong family history of ALS dating back 3 generations, had a point mutation in exon 4, codon 100, GAA to GGA, Glu to Gly) – glu100gly. He was initially recruited into the study in 1998, but as he was unable to tolerate the EDB MUNE test, he elected not to continue to participate in the study. He represented 11 years later with a 3 month history of lower limb weakness, which he noticed only when he walked long distances and up stairs. He

**Months pre and post** -42 -40 -37 -29 -20 -10 0 +11 +21 +27

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**Date of study** Oct-98 Dec-98 Mar-99 Nov-99 Jul-00 Jan-01 Nov-01 Oct-02 Aug-03 Feb-04 **R Handgrip** 60 60 65 65 60 70 65 65 65 65 **R Thenar MUNE** 111 111 117 119 120 114 96 97 86 85 **L Handgrip** 60 55 60 65 63 65 65 60 60 60 **L Thenar MUNE** 117 119 111 89 86 79 81 **R EDB power** 5/5 5/5 5/5 5/5 5/5 5/5 4+/5 4+/5 4+/5 4+/5 **R EDB MUNE** 104 111 119 108 104 92 71 75 75 65 **L EDB power** 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 5/5 **L EDB MUNE** 112 89 80 80 81

On examination, he had no evidence of wasting, but there were muscle fasciculations seen in his right quadriceps. His tone was normal in the upper and lower limbs and he had MRC grade 5/5 power in all muscle groups, proximally and distally. His sensory examination was normal

Nerve conduction studies performed by independent neurologist were normal, with no evidence of a large fibre peripheral neuropathy and normal CMAP amplitudes. Needle EMG studies was also normal, with no evidence of active or chronic denervation in bilateral distal and proximal muscles sampled. Using the same MUNE machine and computer algorithm, as 1998, a reduction in his APB MUNE was detectable. Despite the "normal EMG" findings, a presumptive diagnosis of fALS was made. He was commenced on Riluzole therapy 50 mg twice a day. Within 3 months, he noticed an improvement in the symptoms and there was a detectable improvement in MUNE by 40-52%. He was able to walk up stairs easier, walk 100 metres without stopping and lower limb cramps and fasciculations disappeared. Unfortu‐ nately, due to poor tolerance, further studies have not been possible. MUNE results are shown

had also been experiencing lower limb cramps and muscle fasciculations for years.

**Table 4.** Case 1 progressive handgrip, dorsiflexion power and thenar and EDB MUNE results

to touch, vibration and position. His gait was normal.

Over the next 6 months, there was a reduction in her right thenar MUNE to 96 (20%) and her left thenar MUNE to 89 (19%), with no detectable weakness. Her right EDB MUNE also dropped from 111 to 92 (17%), but she only had detectable weakness 10 months later of MRC grade 4+/5 in right dorsiflexors, at which time her right EDB MUNE had dropped further to 71 motor units (35%). The left EDB MUNE also dropped from a baseline of 112 (2 years previously) to 89 (20%), but with no detectable weakness.

An independent neurologist performed needle EMG examination, which showed high amplitude motor units with reduced recruitment in vastus medialis, tibialis anterior and extensor carpi radialis longus, bilaterally but no fibrillation potentials were seen. It was felt that these changes were not enough to make the diagnosis of ALS.

In view of her strong family history, a presumed diagnosis of familial ALS was made and she was commenced on Riluzole in February 2002.

Over the next 3 years, her EDB MUNE results have stabilised. Her weakness has not progressed significantly. In February 2004, she still had MRC grade 4+/5 power of her right dorsiflexors and no symptomatically apparent weakness in her left dorsiflexors or upper limbs.


**Table 4.** Case 1 progressive handgrip, dorsiflexion power and thenar and EDB MUNE results

#### *7.5.2. Case study 2*

wasting, weakness or fasciculation. Her right and left thenar MUNE's remained stable for the first 2½ years of the study at around 115-120 motor units. Progress MUNE results are shown

Over the next 6 months, there was a reduction in her right thenar MUNE to 96 (20%) and her left thenar MUNE to 89 (19%), with no detectable weakness. Her right EDB MUNE also dropped from 111 to 92 (17%), but she only had detectable weakness 10 months later of MRC grade 4+/5 in right dorsiflexors, at which time her right EDB MUNE had dropped further to 71 motor units (35%). The left EDB MUNE also dropped from a baseline of 112 (2 years

An independent neurologist performed needle EMG examination, which showed high amplitude motor units with reduced recruitment in vastus medialis, tibialis anterior and extensor carpi radialis longus, bilaterally but no fibrillation potentials were seen. It was felt

In view of her strong family history, a presumed diagnosis of familial ALS was made and she

Over the next 3 years, her EDB MUNE results have stabilised. Her weakness has not progressed significantly. In February 2004, she still had MRC grade 4+/5 power of her right dorsiflexors

and no symptomatically apparent weakness in her left dorsiflexors or upper limbs.

in Table 4 and Figures 11.

**Figure 10.** Pedigree of cases 1, 2 and 3

206 Current Advances in Amyotrophic Lateral Sclerosis

previously) to 89 (20%), but with no detectable weakness.

was commenced on Riluzole in February 2002.

that these changes were not enough to make the diagnosis of ALS.

A 57-year-old man with a strong family history of ALS dating back 3 generations, had a point mutation in exon 4, codon 100, GAA to GGA, Glu to Gly) – glu100gly. He was initially recruited into the study in 1998, but as he was unable to tolerate the EDB MUNE test, he elected not to continue to participate in the study. He represented 11 years later with a 3 month history of lower limb weakness, which he noticed only when he walked long distances and up stairs. He had also been experiencing lower limb cramps and muscle fasciculations for years.

On examination, he had no evidence of wasting, but there were muscle fasciculations seen in his right quadriceps. His tone was normal in the upper and lower limbs and he had MRC grade 5/5 power in all muscle groups, proximally and distally. His sensory examination was normal to touch, vibration and position. His gait was normal.

Nerve conduction studies performed by independent neurologist were normal, with no evidence of a large fibre peripheral neuropathy and normal CMAP amplitudes. Needle EMG studies was also normal, with no evidence of active or chronic denervation in bilateral distal and proximal muscles sampled. Using the same MUNE machine and computer algorithm, as 1998, a reduction in his APB MUNE was detectable. Despite the "normal EMG" findings, a presumptive diagnosis of fALS was made. He was commenced on Riluzole therapy 50 mg twice a day. Within 3 months, he noticed an improvement in the symptoms and there was a detectable improvement in MUNE by 40-52%. He was able to walk up stairs easier, walk 100 metres without stopping and lower limb cramps and fasciculations disappeared. Unfortu‐ nately, due to poor tolerance, further studies have not been possible. MUNE results are shown in Table 5.

Nerve conduction studies performed by independent neurologist were normal, with no evidence of a large fibre peripheral neuropathy. Needle EMG studies was also normal, with no evidence of active or chronic denervation in bilateral distal and proximal muscles

**Table 5.** showing progressive handgrip, dorsiflexion power, thenar and EDB MUNE and needle EMG results of Case 2 (Normal EMG refers to the absence of fasciculation and fibrillation potentials, normal motor unit potentials and

**May-98 July-09 Nov-09**

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**Riluzole commenced**

86 (56% decrease)

125 45% increase)

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90 (52% increase)

94 (40% increase)

**Months Baseline 13 months 4 months**

**R Handgrip** 105 95 80 **L Handgrip** 110 105 90

**L APB MUNE** 88 124

On her initial MUNE testing, results were within normal values, but 5 months later, there was a detectable reduction in her MUNE's from baseline of between 13-23%. As the MUNE change was greater than our re-retest reliability limits (<5%), a presumptive diagnosis fALS was made and commenced on Riluzole therapy. This resulted in an improvement in her fasciculations and MUNE's over the next 6 months, 14-41%. Her MUNE results have remained stable over

A 47-year-old lady with a family history of dominantly inherited non-SOD 1 ALS, (father aged 68 and brother aged 45, both died of ALS). A point mutation in the SOD 1 gene has not been currently detected. She presented with a 1-year history of generalised muscle fasciculations and occasional lower limb cramps. She had generalised tiredness and muscular aches and pains, but no weakness, numbness or paraesthesia. Her gait was steady. As a result of her

the next 12 months. Progress MUNE results are shown in Table 6.

symptoms, she ceased work in March 2004.

**R APB MUNE** 198

**R ADM MUNE** 110 95 **L ADM MUNE** 85

**R EDB MUNE** Not tolerated 59

**L EDB MUNE** 67

**Needle EMG** Normal Normal

sampled.

normal recruitment)

*7.5.4. Case study 4*

**Figure 11.** Progressive results of case 1 showing the change in APB and EDB motor unit estimates over time in relation to handgrip strength and power. There is a reduction of APB and EDB MUNE even though strength has remained sta‐ ble.

#### *7.5.3. Case study 3*

A 43-year old lady with an extensive family history of ALS dating back 4 generations, had a point mutation in exon 5, codon 148, GTA to GGA, Val to Gly) – val148gly. She presented with generalised muscle fasciculations, but no weakness or cramps.

On examination, she had no wasting or fasciculations. Her tone, power, reflexes and sensation in the upper and lower limbs were normal. Her gait was steady and she was able to walk on her heels and toes. Tandem walking was normal and Romberg's sign was negative.


**Table 5.** showing progressive handgrip, dorsiflexion power, thenar and EDB MUNE and needle EMG results of Case 2 (Normal EMG refers to the absence of fasciculation and fibrillation potentials, normal motor unit potentials and normal recruitment)

Nerve conduction studies performed by independent neurologist were normal, with no evidence of a large fibre peripheral neuropathy. Needle EMG studies was also normal, with no evidence of active or chronic denervation in bilateral distal and proximal muscles sampled.

On her initial MUNE testing, results were within normal values, but 5 months later, there was a detectable reduction in her MUNE's from baseline of between 13-23%. As the MUNE change was greater than our re-retest reliability limits (<5%), a presumptive diagnosis fALS was made and commenced on Riluzole therapy. This resulted in an improvement in her fasciculations and MUNE's over the next 6 months, 14-41%. Her MUNE results have remained stable over the next 12 months. Progress MUNE results are shown in Table 6.

#### *7.5.4. Case study 4*

*7.5.3. Case study 3*

ble.

0

40

80

**EDB MUNE**

120

160

0

40

80

**APB MUNE**

120

160

208 Current Advances in Amyotrophic Lateral Sclerosis

A 43-year old lady with an extensive family history of ALS dating back 4 generations, had a point mutation in exon 5, codon 148, GTA to GGA, Val to Gly) – val148gly. She presented with

**Figure 11.** Progressive results of case 1 showing the change in APB and EDB motor unit estimates over time in relation to handgrip strength and power. There is a reduction of APB and EDB MUNE even though strength has remained sta‐

0

0

1

2

3

**MRC grade power**

R EDB MUNE L EDB MUNE R Dorsiflexion power L Dorsiflexion power

4

5

20

40

**Handgrip (lbs)**

R APB MUNE L APB MUNE R Handgrip L Handgrip

60

80

On examination, she had no wasting or fasciculations. Her tone, power, reflexes and sensation in the upper and lower limbs were normal. Her gait was steady and she was able to walk on

her heels and toes. Tandem walking was normal and Romberg's sign was negative.

Oct-98 Dec-98 Mar-99 Nov-99 Nov-00 Jan-01 Nov-01 Oct-02 Aug-03 Feb-04

**Date**

generalised muscle fasciculations, but no weakness or cramps.

Oct-98 Dec-98 Mar-99 Nov-99 Nov-00 Jan-01 Nov-01 Oct-02 Aug-03 Feb-04

**Date**

A 47-year-old lady with a family history of dominantly inherited non-SOD 1 ALS, (father aged 68 and brother aged 45, both died of ALS). A point mutation in the SOD 1 gene has not been currently detected. She presented with a 1-year history of generalised muscle fasciculations and occasional lower limb cramps. She had generalised tiredness and muscular aches and pains, but no weakness, numbness or paraesthesia. Her gait was steady. As a result of her symptoms, she ceased work in March 2004.


and pains and fasciculations recurred. Her subsequent MUNE study was blinded, as the operator was unaware that Riluzole had been ceased and found that her EDB MUNE's had reduced once again. She then had a 3rd needle EMG study, which was once again normal. She also had a MRI scan of her brain and full spine that showed no significant abnormality. She was recommenced on Riluzole, which resulted in a slow and steady improvement in her MUNE, which she has been maintained. Progress MUNE results are shown in Table 7 and

> R Thenar MUNE L Thenar MUNE R EDB MUNE L EDB MUNE

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**Date of Study**

**Figure 12.** showing progressive thenar and EDB MUNE changes in relation to changes in the dose of Riluzole in Case 4

Motor neurone disease (MND) is a group of fatal, progressive neurodegenerative disorders, with an overall median survival is approximately 4.0 years from the onset of symptoms. By the time most patients with MND are aware of clinical weakness and seek review by their primary physician or neurologist, a significant proportion of motor units have already been lost. Early detection of motor neurone loss in clinically apparently unaffected muscles is

Motor unit number estimates in the group of asymptomatic SOD1 mutation carriers were compared to age and sex matched family controls without the SOD1 mutation, and sporadic (non-SOD1) MND patients. There was no detectable difference in the number of thenar motor units in the group of asymptomatic SOD1 mutation carriers compared to the group of SOD1 negative family controls (thenar p>0.46), or population controls (thenar p>0.70).. In addition,

therefore important to establish an early diagnosis of the condition.

Re-Start Riluzole

Reduced dose to daily Increased back to bd

The Role of the Statistical Method of Motor Unit Number Estimation (MUNE) to…

Figure 12.

0

40

80

**MUNE**

**8. Conclusion**

120

160

Start Riluzole Ceased Riluzole

**Table 6.** showing progressive handgrip, dorsiflexion power, thenar and EDB MUNE and needle EMG results of Case 3 (Normal EMG refers to the absence of fasciculation and fibrillation potentials, normal motor unit potentials and normal recruitment)

On examination, she had no evidence of wasting, but there were generalised fasciculations, especially in the triceps and quadriceps regions. Her tone was normal in the upper and lower limbs. She had no clinical weakness with MRC grade 5/5 power in all muscle groups, proxi‐ mally and distally. Her sensory examination was normal to touch, vibration and position. Her reflexes were all present and symmetrical. Her gait was normal, as she was able to walk on her heels and toes. She was able to perform tandem walking and Romberg's sign was negative.

Nerve conduction studies performed by independent neurologist were normal, with no evidence of a large fibre peripheral neuropathy. Needle EMG studies was also normal, with no evidence of active or chronic denervation in bilateral distal and proximal muscles sampled.

Initial EDB MUNE was reduced with normal APB MUNE's. Despite this, a clinical diagnosis on fALS was not made given her normal needle EMG study, and she was observed over the next 6 months. Over this time, she developed MRC grade 4/5 weakness of ankle dorsiflexion, bilaterally and her EDB MUNE dropped by 14-20%. Despite this reduction, compound muscle action potential amplitudes were maintained. Needle EMG studies were repeated and once again normal there was no spontaneous activity (fibrillation potentials) and motor unit recruitment was normal, despite the presence of weakness.

Given her family history, a presumptive diagnosis of non-SOD 1 fALS was made and com‐ menced on Riluzole therapy. This resulted in an improvement in clinical symptoms of tiredness and fasciculations, allowing her to return to work. Her EDB MUNE improved by 34-60%, and increased further over the next year. Despite this, her treating neurologist considered this was a placebo effect and ceased Riluzole. Within 2 weeks, her generalised aches and pains and fasciculations recurred. Her subsequent MUNE study was blinded, as the operator was unaware that Riluzole had been ceased and found that her EDB MUNE's had reduced once again. She then had a 3rd needle EMG study, which was once again normal. She also had a MRI scan of her brain and full spine that showed no significant abnormality. She was recommenced on Riluzole, which resulted in a slow and steady improvement in her MUNE, which she has been maintained. Progress MUNE results are shown in Table 7 and Figure 12.

**Figure 12.** showing progressive thenar and EDB MUNE changes in relation to changes in the dose of Riluzole in Case 4
