**7. Results**

642 Amyotrophic Lateral Sclerosis

All results were entered into a database and analysed using a standard statistical software package (SPSS 9.05 for Windows). For the initial part of the study, the MUNE results from asymptomatic SOD1 mutation carriers were grouped together. Although different mutations in SOD1 have different effects on the progression of the disease once symptoms

Motor unit estimates in 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. Although there were some outlying results, the distributions were not sufficiently skewed to contradict the use of the t-test. Statistical significance was accepted at a p-value of <0.05. The group of asymptomatic SOD1 mutation carriers were followed over the next 2 to 5 years, depending on the volunteers' motivation, both clinically and by MUNE. Results were compared to their initial baseline MUNE and the date of the study when this reduction was

It has been suggested that the traditional neurological examination is inadequate for documenting motor performance impairment with reliability. (Hanten et al., 1999). Generally, manual motor testing used in a standard neurological motor examination does not allow objective documentation of change in performance, as it may be influenced by the patient's history and progress. Major changes are apparent, but subtle changes are difficult

There are a number of methods that have been developed to quantify maximal voluntary isometric contraction (MVIC). It has been proposed that this is a clinically useful, reliable, 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

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

occur, these different mutations do not influence on the age of onset of symptoms.67

first detected, was used as the date when motor neurone loss commenced.

**6.4 Maximal voluntary isometric contraction testing** 

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

grading system and compared to thenar (APB) MUNE.

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

to determine with accuracy.
